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COMET ISON: ORANGE ALERT

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  • iferrinv
    Hi all: I have placed comet ISON in ORANGE ALERT. The reason? The secular light curve is showing signs of leveling off:
    Message 1 of 26 , Oct 9, 2013

      Hi all:
      I have placed comet ISON in ORANGE ALERT.
      The reason?  The secular light curve is showing 
      signs of leveling off:   

      http://astronomia.udea.edu.co/cometspage

      In the past, with comets LINEAR, Tabur, Honig and 
      Elenin, just after the leveling off, the comet 
      disintegrated.

      WE NEED URGENT CONFIRMATION OF THIS TREND

      I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
      TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT

      respuestas2013 at gmail.com

      as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
      SEND YOUR *SERIES*.  Use a simple .txt format

      YEAR MONTH DAY MAGNITUDE

      The first time you do specify the instrument aperture, band
      and type.   If you do that:

      a) you will make my life easier.
      b) I will be able to update the light curve daily
      c) you will appear in the light curve
      d) you will help define the trend 

      I have  evidence to conclude 
      that the comet is shedding off large particles, as 
      large as 1 cm or even larger.    If you look at the
      images, there are no filaments, there are no
      streamers, just a diffuse light consistent with a 
      dust tail.

      Accordingly light from the continuum would dominate
      over the gas.

      Could anybody take a spectrum of the comet in the 
      visual and publish it as soon as possible ? 
      Can anybody confirm or deny this ?

      Kind regards,
      Ignacio
      Institute of Physics
      University of Antioquia
      oooooooooooooooooooooooooooooooooooo
    • P. Edward Murray
      How long does it take between Leveling off as you say and when the comet breaks apart? Ed Murray BMAA, Inc On 10/09/13, ferrin@ula.ve wrote: Hi all: I have
      Message 2 of 26 , Oct 9, 2013
         
         
         How long does it take between "Leveling off" as you say and when the comet breaks apart?
         
        Ed Murray
        BMAA, Inc
        On 10/09/13, ferrin@... wrote:
         
         

        Hi all:
        I have placed comet ISON in ORANGE ALERT.
        The reason?  The secular light curve is showing 
        signs of leveling off:   


        In the past, with comets LINEAR, Tabur, Honig and 
        Elenin, just after the leveling off, the comet 
        disintegrated.

        WE NEED URGENT CONFIRMATION OF THIS TREND

        I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
        TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT

        respuestas2013 at gmail.com

        as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
        SEND YOUR *SERIES*.  Use a simple .txt format

        YEAR MONTH DAY MAGNITUDE

        The first time you do specify the instrument aperture, band
        and type.   If you do that:

        a) you will make my life easier.
        b) I will be able to update the light curve daily
        c) you will appear in the light curve
        d) you will help define the trend 

        I have  evidence to conclude 
        that the comet is shedding off large particles, as 
        large as 1 cm or even larger.    If you look at the
        images, there are no filaments, there are no
        streamers, just a diffuse light consistent with a 
        dust tail.

        Accordingly light from the continuum would dominate
        over the gas.

        Could anybody take a spectrum of the comet in the 
        visual and publish it as soon as possible ? 
        Can anybody confirm or deny this ?

        Kind regards,
        Ignacio
        Institute of Physics
        University of Antioquia
        oooooooooooooooooooooooooooooooooooo
      • skyweek
        Three items today on how ISON is not only doing fine right now but will be probably be doing even better come perihelion: http://www.psi.edu/news/ISON3.html -
        Message 3 of 26 , Oct 9, 2013
          Three items today on how ISON is not only doing fine right now but will be
          probably be doing even better come perihelion:

          http://www.psi.edu/news/ISON3.html -> ISON's rotation axis may now have
          been nailed (from the orientation of the sunward jet in the April HST
          image series and later groundbased images as Li just explained at a DPS
          press conference) -> in the last week before perihelion fresh surface
          should get exposed to the Sun for the first time, including potential
          pockets of supervolatiles which would then "sublimate like crazy" (Li's
          words) and drive a lot of dust into coma & tail.

          http://www.nature.com/news/comet-expected-to-survive-close-sun-encounter-1.13924
          -> about the well-known paper by Walsh et al. which makes a detailled case
          that it is more likely than not that ISON's nucleus survives perihelion;
          one of the authors just reiterated this conclusion at said press
          conference.

          http://www.isoncampaign.org/karl/ison-is-just-fine -> great summary of the
          current, healthy state of ISON, based on actual hi-res images. (New HST
          images should actually have been taken last night, so we might get more
          near-nucleus insights shortly.)

          Enjoy,

          Daniel
          kometison.de
        • Bob King
          Thanks Daniel for these links. The imminent demise talk sounds crazy to me. The comet remains relatively bright and getting brighter. Bob
          Message 4 of 26 , Oct 9, 2013
            Thanks Daniel for these links. The imminent demise talk sounds crazy to me. The comet remains relatively bright and getting brighter.
            Bob


            On Wed, Oct 9, 2013 at 2:23 PM, <dfischer@...-bonn.de> wrote:
             

            Three items today on how ISON is not only doing fine right now but will be
            probably be doing even better come perihelion:

            http://www.psi.edu/news/ISON3.html -> ISON's rotation axis may now have
            been nailed (from the orientation of the sunward jet in the April HST
            image series and later groundbased images as Li just explained at a DPS
            press conference) -> in the last week before perihelion fresh surface
            should get exposed to the Sun for the first time, including potential
            pockets of supervolatiles which would then "sublimate like crazy" (Li's
            words) and drive a lot of dust into coma & tail.

            http://www.nature.com/news/comet-expected-to-survive-close-sun-encounter-1.13924
            -> about the well-known paper by Walsh et al. which makes a detailled case
            that it is more likely than not that ISON's nucleus survives perihelion;
            one of the authors just reiterated this conclusion at said press
            conference.

            http://www.isoncampaign.org/karl/ison-is-just-fine -> great summary of the
            current, healthy state of ISON, based on actual hi-res images. (New HST
            images should actually have been taken last night, so we might get more
            near-nucleus insights shortly.)

            Enjoy,

            Daniel
            kometison.de


          • P. Clay Sherrod
            Orange Alert? I think this is entering the realm of silliness at this point. There is absolutely no evidence that ISON is breaking up. Clay _____ Dr. P.
            Message 5 of 26 , Oct 9, 2013
              
              "Orange Alert?"
              I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
               
              Clay
              _____
              Dr. P. Clay Sherrod
              Arkansas Sky Observatories
              MPC H45 - Petit Jean Mountain South
              MPC H41 - Petit Jean Mountain
              MPC H43 - Conway West
              http://www.arksky.org/
              ----- Original Message -----
              Sent: Wednesday, October 09, 2013 1:38 PM
              Subject: Re: [comets-ml] COMET ISON: ORANGE ALERT

               
               
               How long does it take between "Leveling off" as you say and when the comet breaks apart?
               
              Ed Murray
              BMAA, Inc
              On 10/09/13, ferrin@... wrote:
               
               

              Hi all:
              I have placed comet ISON in ORANGE ALERT.
              The reason?  The secular light curve is showing 
              signs of leveling off:   


              In the past, with comets LINEAR, Tabur, Honig and 
              Elenin, just after the leveling off, the comet 
              disintegrated.

              WE NEED URGENT CONFIRMATION OF THIS TREND

              I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
              TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT

              respuestas2013 at gmail.com

              as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
              SEND YOUR *SERIES*.  Use a simple .txt format

              YEAR MONTH DAY MAGNITUDE

              The first time you do specify the instrument aperture, band
              and type.   If you do that:

              a) you will make my life easier.
              b) I will be able to update the light curve daily
              c) you will appear in the light curve
              d) you will help define the trend 

              I have  evidence to conclude 
              that the comet is shedding off large particles, as 
              large as 1 cm or even larger.    If you look at the
              images, there are no filaments, there are no
              streamers, just a diffuse light consistent with a 
              dust tail.

              Accordingly light from the continuu m would dominate
              over the gas.

              Could anybody take a spectrum of the comet in the 
              visual and publish it as soon as possible ? 
              Can anybody confirm or deny this ?

              Kind regards,
              Ignacio
              Institute of Physics
              University of Antioquia
              oooooooooooooooooooooooooooooooooooo
            • Daniel Janosick
              Dr. Clay, I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on beyond speculation to a
              Message 6 of 26 , Oct 9, 2013
                Re: [comets-ml] COMET ISON: ORANGE ALERT Dr. Clay,
                   I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on   beyond speculation to a point of... Well like you said just plain silliness. But one thing is for sure, this is EXCITING.

                Dan



                On 10/9/13 3:49 PM, "P. Clay Sherrod" <drclay@...> wrote:


                 
                 
                   

                
                "Orange Alert?"
                I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                 
                Clay
                _____
                Dr. P. Clay Sherrod
                Arkansas Sky Observatories
                MPC H45 - Petit Jean Mountain South
                MPC H41 - Petit Jean Mountain
                MPC H43 - Conway West
                http://www.arksky.org/

                ----- Original Message -----
                 
                From:  P. Edward  Murray <mailto:ed1ward2@...>  
                 
                To: comets-ml@yahoogroups.com
                 
                Sent: Wednesday, October 09, 2013 1:38  PM
                 
                Subject: Re: [comets-ml] COMET ISON:  ORANGE ALERT
                 

                 
                 
                 
                 
                 
                 
                 How long does it take between "Leveling off" as you say and when  the comet breaks apart?
                 
                 
                 
                Ed Murray
                 
                BMAA, Inc
                 
                On 10/09/13,  ferrin@... wrote:
                 
                 
                   
                 
                 
                 

                 

                 
                Hi all:
                 
                I have placed comet ISON in ORANGE ALERT.
                 
                The reason?  The secular light curve is showing
                 
                signs of leveling off:   
                 

                 
                http://astronomia.u dea.edu.co/cometspage
                 

                 
                In the past, with comets
                LINEAR,  Tabur, Honig and

                Elenin, just after the leveling off, the comet

                disintegrated.


                 
                WE NEED URGENT CONFIRMATION OF THIS TREND
                 

                 
                I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                 
                TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                 

                 
                respuestas2013 at gmail.com
                 

                 
                as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                 
                SEND YOUR *SERIES*.  Use a simple .txt format
                 

                 
                YEAR MONTH DAY MAGNITUDE
                 

                 
                The first time you do specify the instrument aperture, band
                 
                and type.   
                If you do  that:


                 
                a) you will make my life easier.
                 
                b) I will be able to update the light curve daily
                 
                c) you will appear in the light curve
                 
                d) you will help define the trend
                 

                 
                I have  evidence to conclude

                that the comet is  shedding off large particles,  as

                large as 1 cm or even larger.    If you look at the

                images, there are no filaments, there are  no

                streamers, just a diffuse light consistent  with a

                dust tail.


                 
                 
                Accordingly light from
                the continuu m  would dominate

                over the gas.


                 
                 
                Could anybody take a spectrum
                of the  comet in the

                visual and publish it as soon as possible ?

                Can anybody confirm or deny this  ?


                 
                Kind regards,
                 
                Ignacio

                Institute of Physics

                University of Antioquia

                oooooooooooooooooooooooooooooooooooo

                 

                   




                From the Desk of
                Daniel Andrew Janosick

              • tricks46
                Yea----I must have missed another color chart. Can someone point me to the chart that shows the different colors and what they mean?
                Message 7 of 26 , Oct 9, 2013
                  Yea----I must have missed another color chart. Can someone point me to the chart that shows the different colors and what they mean?

                  --- In comets-ml@yahoogroups.com, <ferrin@...> wrote:
                  >
                  >
                  > Hi all:
                  > I have placed comet ISON in ORANGE ALERT.
                  > The reason? The secular light curve is showing
                  > signs of leveling off:
                  >
                  >
                  > http://astronomia.udea.edu.co/cometspage
                  >
                  >
                  > In the past, with comets LINEAR, Tabur, Honig and
                  > Elenin, just after the leveling off, the comet
                  > disintegrated.
                  >
                  >
                  > WE NEED URGENT CONFIRMATION OF THIS TREND
                  >
                  >
                  > I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                  > TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                  >
                  >
                  > respuestas2013 at gmail.com
                  >
                  >
                  > as soon as possible. DO NOT SEND ISOLATED OBSERVATIONS.
                  > SEND YOUR *SERIES*. Use a simple .txt format
                  >
                  >
                  > YEAR MONTH DAY MAGNITUDE
                  >
                  >
                  > The first time you do specify the instrument aperture, band
                  > and type. If you do that:
                  >
                  >
                  > a) you will make my life easier.
                  > b) I will be able to update the light curve daily
                  > c) you will appear in the light curve
                  > d) you will help define the trend
                  >
                  >
                  > I have evidence to conclude
                  >
                  > that the comet is shedding off large particles, as
                  > large as 1 cm or even larger. If you look at the
                  > images, there are no filaments, there are no
                  > streamers, just a diffuse light consistent with a
                  > dust tail.
                  >
                  >
                  > Accordingly light from the continuum would dominate
                  > over the gas.
                  >
                  >
                  >
                  > Could anybody take a spectrum of the comet in the
                  > visual and publish it as soon as possible ?
                  >
                  > Can anybody confirm or deny this ?
                  >
                  >
                  >
                  > Kind regards,
                  > Ignacio
                  >
                  > Institute of Physics
                  > University of Antioquia
                  > oooooooooooooooooooooooooooooooooooo
                  >
                • P. Edward Murray
                  Dr Sherrod, As a member of Slooh Observatory, we have been imaging Comet Ison and we are still not detecting any fragmentation using our half meter
                  Message 8 of 26 , Oct 9, 2013
                    Dr Sherrod,
                     
                    As a member of Slooh Observatory, we have been imaging Comet Ison and we are "still" not detecting any fragmentation using our half meter telescope.
                     
                    Ed Murray
                     
                     
                    On 10/09/13, P. Clay Sherrod<drclay@...> wrote:
                     
                     

                    

                    "Orange Alert?"
                    I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                     
                    Clay
                    _____
                    Dr. P. Clay Sherrod
                    Arkansas Sky Observatories
                    MPC H45 - Petit Jean Mountain South
                    MPC H41 - Petit Jean Mountain
                    MPC H43 - Conway West
                    http://www.arksky.org/
                    ----- Original Message -----
                    Sent: Wednesday, October 09, 2013 1:38 PM
                    Subject: Re: [comets-ml] COMET ISON: ORANGE ALERT

                     
                     
                     How long does it take between "Leveling off" as you say and when the comet breaks apart?
                     
                    Ed Murray
                    BMAA, Inc
                    On 10/09/13, ferrin@... wrote:
                     
                     

                    Hi all:
                    I have placed comet ISON in ORANGE ALERT.
                    The reason?  The secular light curve is showing 
                    signs of leveling off:   


                    In the past, with comets LINEAR, Tabur, Honig and 
                    Elenin, just after the leveling off, the comet 
                    disintegrated.

                    WE NEED URGENT CONFIRMATION OF THIS TREND

                    I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                    TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT

                    respuestas2013 at gmail.com

                    as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                    SEND YOUR *SERIES*.  Use a simple .txt format

                    YEAR MONTH DAY MAGNITUDE

                    The first time you do specify the instrument aperture, band
                    and type.   If you do that:

                    a) you will make my life easier.
                    b) I will be able to update the light curve daily
                    c) you will appear in the light curve
                    d) you will help define the trend 

                    I have  evidence to conclude 
                    that the comet is shedding off large particles, as 
                    large as 1 cm or even larger.    If you look at the
                    images, there are no filaments, there are no
                    streamers, just a diffuse light consistent with a 
                    dust tail.

                    Accordingly light from the continuu m would dominate
                    over the gas.

                    Could anybody take a spectrum of the comet in the 
                    visual and publish it as soon as possible ? 
                    Can anybody confirm or deny this ?

                    Kind regards,
                    Ignacio
                    Institute of Physics
                    University of Antioquia
                    oooooooooooooooooooooooooooooooooooo
                  • Alan Hale
                    Hello everyone, I ll throw in my $0.02 worth again . . . I observed the comet this morning, and got m1=11.1 ï a slight brightening since my previous
                    Message 9 of 26 , Oct 9, 2013
                      Hello everyone,

                      I'll throw in my $0.02 worth again . . . 

                      I observed the comet this morning, and got m1=11.1 — a slight brightening since my previous observation late last week. It perhaps didn't seem quite as "solid" as it did before, but that is a rather ill-defined concept and I wouldn't read too much into that at this point.

                      Just for fun, I've compared ISON's present brightness to that of a few other recent comets at the same heliocentric distance (and taking into account the varying distances from Earth):

                      C/2011 L4: ISON is almost three magnitudes fainter than this comet was at the same heliocentric distance. C/2011 L4 was not accessible from my latitude at the time, so I used a consensus of what southern hemisphere observers were reporting then.

                      C/2010 X1: ISON is approximately two magnitudes brighter than this comet was at the same heliocentric distance, based upon my observations at the time.

                      C/2009 R1: the moon was full near the time the comet was at this heliocentric distance, but based upon my observations before and after this, ISON is perhaps a half-magnitude or so fainter than this comet was at this distance. 

                      C/1999 S4: unfortunately this comet was at too small an elongation to observe at the time it was at the same heliocentric distance, but I picked it up in the morning sky eleven days later. Making some allowance for this, this comet's brightness was fairly similar to what ISON's brightness is now.


                      Draw your own conclusions . . .  I still think the comet can go either way.


                      Sincerely,

                      Alan
                    • Jakub Cerny
                      Hello All, there is fresh work of Z. Sekanina with very interesting results. http://arxiv.org/pdf/1310.1980v1.pdf Disintegrating comets hould have strong
                      Message 10 of 26 , Oct 9, 2013
                        Hello All,

                        there is fresh work of Z. Sekanina with very interesting results.
                        http://arxiv.org/pdf/1310.1980v1.pdf

                        Disintegrating comets hould have strong non-gravitional forces because when small nucleus disintegrating, strong "rocket effect" push against light body. Actual orbit of comet ISON clearly show that its non-gravitional forces are very weak, therefore nucleus have enough mass and it is not disintegrating.

                        Also actual light curve based on visual and CCD total coma magnitudes showing that comet is brightening well, except the CO outburst phase while that it brightened then faded back on normal phase, see graph bellow:
                        http://gloria.fzu.cz/datas/users/1/ison-lc-actual_1.png

                        Best regards,
                        Jakub Cerny

                        On 10/09/2013 11:48 PM, Alan Hale wrote:
                         
                        Hello everyone,

                        I'll throw in my $0.02 worth again . . . 

                        I observed the comet this morning, and got m1=11.1 — a slight brightening since my previous observation late last week. It perhaps didn't seem quite as "solid" as it did before, but that is a rather ill-defined concept and I wouldn't read too much into that at this point.

                        Just for fun, I've compared ISON's present brightness to that of a few other recent comets at the same heliocentric distance (and taking into account the varying distances from Earth):

                        C/2011 L4: ISON is almost three magnitudes fainter than this comet was at the same heliocentric distance. C/2011 L4 was not accessible from my latitude at the time, so I used a consensus of what southern hemisphere observers were reporting then.

                        C/2010 X1: ISON is approximately two magnitudes brighter than this comet was a t the same heliocentric distance, based upon my observations at the time.

                        C/2009 R1: the moon was full near the time the comet was at this heliocentric distance, but based upon my observations before and after this, ISON is perhaps a half-magnitude or so fainter than this comet was at this distance. 

                        C/1999 S4: unfortunately this comet was at too small an elongation to observe at the time it was at the same heliocentric distance, but I picked it up in the morning sky eleven days later. Making some allowance for this, this comet's brightness was fairly similar to what ISON's brightness is now.


                        Draw your own conclusions . . .  I still think the comet can go either way.


                        Sincerely,

                        Alan

                      • Bomber2 Panther
                        Hi Alan, I like your reasoning, and at the current exchange rate you could have a cent more in Aussie $$ :-) During my observation this morning I noticed the
                        Message 11 of 26 , Oct 9, 2013
                          Hi Alan,
                          I like your reasoning, and at the current exchange rate you could have a cent more in Aussie $$ :-)
                          During my observation this morning I noticed the 12.4 mag star in the coma, my obs came in at mag 10.1. Using comparison stars in the field, and slightly out of, this was my best estimate I could manage, the mag 12.4 star was quite noticeable.
                          My question is how much of an effect would a star of that magnitude have on the observation I made? Using VSS method I had to try my best to ignore the star and concentrate more on the coma itself. Mind you I hadn't seen S1 for 5 days!

                          Cheers,
                          Chris Wyatt
                          Walcha, NSW
                          Australia

                          ________________________________
                          > To: comets-ml@yahoogroups.com
                          > From: ahale@...
                          > Date: Wed, 9 Oct 2013 15:48:31 -0600
                          > Subject: Re: ALL GREEN FOR ISON, was Re: [comets-ml] COMET ISON: ORANGE ALERT
                          >
                          >
                          >
                          > Hello everyone,
                          >
                          > I'll throw in my $0.02 worth again . . .
                          >
                          > I observed the comet this morning, and got m1=11.1 — a slight
                          > brightening since my previous observation late last week. It perhaps
                          > didn't seem quite as "solid" as it did before, but that is a rather
                          > ill-defined concept and I wouldn't read too much into that at this
                          > point.
                          >
                          > Just for fun, I've compared ISON's present brightness to that of a few
                          > other recent comets at the same heliocentric distance (and taking into
                          > account the varying distances from Earth):
                          >
                          > C/2011 L4: ISON is almost three magnitudes fainter than this comet was
                          > at the same heliocentric distance. C/2011 L4 was not accessible from my
                          > latitude at the time, so I used a consensus of what southern hemisphere
                          > observers were reporting then.
                          >
                          > C/2010 X1: ISON is approximately two magnitudes brighter than this
                          > comet was at the same heliocentric distance, based upon my observations
                          > at the time.
                          >
                          > C/2009 R1: the moon was full near the time the comet was at this
                          > heliocentric distance, but based upon my observations before and after
                          > this, ISON is perhaps a half-magnitude or so fainter than this comet
                          > was at this distance.
                          >
                          > C/1999 S4: unfortunately this comet was at too small an elongation to
                          > observe at the time it was at the same heliocentric distance, but I
                          > picked it up in the morning sky eleven days later. Making some
                          > allowance for this, this comet's brightness was fairly similar to what
                          > ISON's brightness is now.
                          >
                          >
                          > Draw your own conclusions . . . I still think the comet can go either way.
                          >
                          >
                          > Sincerely,
                          >
                          > Alan
                          >
                          >
                          >
                        • Jean Meeus
                          Message 12 of 26 , Oct 9, 2013
                            < I have placed comet ISON in ORANGE ALERT.
                            < The reason?  The secular light curve is showing signs of leveling off:   

                            Why do you call it a "secular" light curve? 
                            The word "secular" comes from the Latin "seculus" which means century.

                            Jean Meeus



                            On 9 October 2013 21:57, Daniel Janosick <danjanos@...> wrote:
                             

                            Dr. Clay,
                               I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on   beyond speculation to a point of... Well like you said just plain silliness. But one thing is for sure, this is EXCITING.

                            Dan



                            On 10/9/13 3:49 PM, "P. Clay Sherrod" <drclay@...> wrote:


                             
                             
                               


                            "Orange Alert?"
                            I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                             
                            Clay
                            _____
                            Dr. P. Clay Sherrod
                            Arkansas Sky Observatories
                            MPC H45 - Petit Jean Mountain South
                            MPC H41 - Petit Jean Mountain
                            MPC H43 - Conway West
                            http://www.arksky.org/

                            ----- Original Message -----
                             
                            From:  P. Edward  Murray <mailto:ed1ward2@...>  

                             
                            To: comets-ml@yahoogroups.com
                             
                            Sent: Wednesday, October 09, 2013 1:38  PM
                             
                            Subject: Re: [comets-ml] COMET ISON:  ORANGE ALERT
                             

                             
                             
                             
                             
                             
                             
                             How long does it take between "Leveling off" as you say and when  the comet breaks apart?
                             
                             
                             
                            Ed Murray
                             
                            BMAA, Inc
                             
                            On 10/09/13,  ferrin@... wrote:
                             
                             
                               
                             
                             
                             

                             

                             
                            Hi all:
                             
                            I have placed comet ISON in ORANGE ALERT.
                             
                            The reason?  The secular light curve is showing
                             
                            signs of leveling off:   
                             

                             
                            http://astronomia.u dea.edu.co/cometspage
                             

                             
                            In the past, with comets
                            LINEAR,  Tabur, Honig and

                            Elenin, just after the leveling off, the comet

                            disintegrated.


                             
                            WE NEED URGENT CONFIRMATION OF THIS TREND
                             

                             
                            I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                             
                            TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                             

                             
                            respuestas2013 at gmail.com
                             

                             
                            as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                             
                            SEND YOUR *SERIES*.  Use a simple .txt format
                             

                             
                            YEAR MONTH DAY MAGNITUDE
                             

                             
                            The first time you do specify the instrument aperture, band
                             
                            and type.   
                            If you do  that:


                             
                            a) you will make my life easier.
                             
                            b) I will be able to update the light curve daily
                             
                            c) you will appear in the light curve
                             
                            d) you will help define the trend
                             

                             
                            I have  evidence to conclude

                            that the comet is  shedding off large particles,  as

                            large as 1 cm or even larger.    If you look at the

                            images, there are no filaments, there are  no

                            streamers, just a diffuse light consistent  with a

                            dust tail.


                             
                             
                            Accordingly light from
                            the continuu m  would dominate

                            over the gas.


                             
                             
                            Could anybody take a spectrum
                            of the  comet in the

                            visual and publish it as soon as possible ?

                            Can anybody confirm or deny this  ?


                             
                            Kind regards,
                             
                            Ignacio

                            Institute of Physics

                            University of Antioquia

                            oooooooooooooooooooooooooooooooooooo

                             

                               




                            From the Desk of
                            Daniel Andrew Janosick


                          • stargazer_08121961
                            It does seem hard to figure ISON out. From the images, it seems to be developing just fine, but perhaps if we had as good imagery of some of the other
                            Message 13 of 26 , Oct 10, 2013

                              It does seem hard to figure ISON out.  From the images, it seems to be developing just fine, but perhaps if we had as good imagery of some of the other disintegrated comets, they would have looked good as well.  On the other hand, it seems to that the slope of its brightening is little different from an ordinary reflective body with no cometary activity.  This is not good at all.  Those of us who pray should hope that the it follows a "religious" light curve rather than a "secular" one. 



                              ---In comets-ml@yahoogroups.com, <comets-ml@yahoogroups.com> wrote:

                              < I have placed comet ISON in ORANGE ALERT.
                              < The reason?  The secular light curve is showing signs of leveling off:   

                              Why do you call it a "secular" light curve? 
                              The word "secular" comes from the Latin "seculus" which means century.

                              Jean Meeus



                              On 9 October 2013 21:57, Daniel Janosick <danjanos@...> wrote:
                               

                              Dr. Clay,
                                 I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on   beyond speculation to a point of... Well like you said just plain silliness. But one thing is for sure, this is EXCITING.

                              Dan



                              On 10/9/13 3:49 PM, "P. Clay Sherrod" <drclay@...> wrote:


                               
                               
                                 


                              "Orange Alert?"
                              I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                               
                              Clay
                              _____
                              Dr. P. Clay Sherrod
                              Arkansas Sky Observatories
                              MPC H45 - Petit Jean Mountain South
                              MPC H41 - Petit Jean Mountain
                              MPC H43 - Conway West
                              http://www.arksky.org/

                              ----- Original Message -----
                               
                              From:  P. Edward  Murray <mailto:ed1ward2@...>  

                               
                              To: comets-ml@yahoogroups.com
                               
                              Sent: Wednesday, October 09, 2013 1:38  PM
                               
                              Subject: Re: [comets-ml] COMET ISON:  ORANGE ALERT
                               

                               
                               
                               
                               
                               
                               
                               How long does it take between "Leveling off" as you say and when  the comet breaks apart?
                               
                               
                               
                              Ed Murray
                               
                              BMAA, Inc
                               
                              On 10/09/13,  ferrin@... wrote:
                               
                               
                                 
                               
                               
                               

                               

                               
                              Hi all:
                               
                              I have placed comet ISON in ORANGE ALERT.
                               
                              The reason?  The secular light curve is showing
                               
                              signs of leveling off:   
                               

                               
                              http://astronomia.u dea.edu.co/cometspage
                               

                               
                              In the past, with comets
                              LINEAR,  Tabur, Honig and

                              Elenin, just after the leveling off, the comet

                              disintegrated.


                               
                              WE NEED URGENT CONFIRMATION OF THIS TREND
                               

                               
                              I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                               
                              TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                               

                               
                              respuestas2013 at gmail.com
                               

                               
                              as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                               
                              SEND YOUR *SERIES*.  Use a simple .txt format
                               

                               
                              YEAR MONTH DAY MAGNITUDE
                               

                               
                              The first time you do specify the instrument aperture, band
                               
                              and type.   
                              If you do  that:


                               
                              a) you will make my life easier.
                               
                              b) I will be able to update the light curve daily
                               
                              c) you will appear in the light curve
                               
                              d) you will help define the trend
                               

                               
                              I have  evidence to conclude

                              that the comet is  shedding off large particles,  as

                              large as 1 cm or even larger.    If you look at the

                              images, there are no filaments, there are  no

                              streamers, just a diffuse light consistent  with a

                              dust tail.


                               
                               
                              Accordingly light from
                              the continuu m  would dominate

                              over the gas.


                               
                               
                              Could anybody take a spectrum
                              of the  comet in the

                              visual and publish it as soon as possible ?

                              Can anybody confirm or deny this  ?


                               
                              Kind regards,
                               
                              Ignacio

                              Institute of Physics

                              University of Antioquia

                              oooooooooooooooooooooooooooooooooooo

                               

                                 




                              From the Desk of
                              Daniel Andrew Janosick


                            • costeira1
                              Hi friends, I remember that the concept of Secular Light Curves of Comets was presented at IV IWCA in Rio de Janeiro (August 8, 2009) by Prof. Ignacio
                              Message 14 of 26 , Oct 10, 2013

                                Hi friends,

                                 

                                I remember that the concept of "Secular Light Curves of Comets" was presented at IV IWCA in Rio de Janeiro (August 8, 2009) by Prof. Ignacio Ferrín and this paper at this URL can be useful to understand it:

                                 

                                http://arxiv.org/ftp/arxiv/papers/0909/0909.3498.pdf

                                 

                                []s Alex!



                                ---In comets-ml@yahoogroups.com, <comets-ml@yahoogroups.com> wrote:

                                < I have placed comet ISON in ORANGE ALERT.
                                < The reason?  The secular light curve is showing signs of leveling off:   

                                Why do you call it a "secular" light curve? 
                                The word "secular" comes from the Latin "seculus" which means century.

                                Jean Meeus
                              • Juan Lacruz
                                The comet would disintegrate due to tidal forces once inside the solar Roche s limit about 3 solar radii, now it is far outside this region. Juan
                                Message 15 of 26 , Oct 10, 2013
                                  The comet would disintegrate due to tidal forces once inside the solar Roche's limit about 3 solar radii, now it is far outside this region.
                                  Juan 


                                  On Thu, Oct 10, 2013 at 2:06 PM, <stargazer_08121961@...> wrote:
                                   

                                  It does seem hard to figure ISON out.  From the images, it seems to be developing just fine, but perhaps if we had as good imagery of some of the other disintegrated comets, they would have looked good as well.  On the other hand, it seems to that the slope of its brightening is little different from an ordinary reflective body with no cometary activity.  This is not good at all.  Those of us who pray should hope that the it follows a "religious" light curve rather than a "secular" one. 



                                  ---In comets-ml@yahoogroups.com, <comets-ml@yahoogroups.com> wrote:

                                  < I have placed comet ISON in ORANGE ALERT.
                                  < The reason?  The secular light curve is showing signs of leveling off:   

                                  Why do you call it a "secular" light curve? 
                                  The word "secular" comes from the Latin "seculus" which means century.

                                  Jean Meeus



                                  On 9 October 2013 21:57, Daniel Janosick <danjanos@...> wrote:
                                   

                                  Dr. Clay,
                                     I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on   beyond speculation to a point of... Well like you said just plain silliness. But one thing is for sure, this is EXCITING.

                                  Dan



                                  On 10/9/13 3:49 PM, "P. Clay Sherrod" <drclay@...> wrote:


                                   
                                   
                                     


                                  "Orange Alert?"
                                  I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                                   
                                  Clay
                                  _____
                                  Dr. P. Clay Sherrod
                                  Arkansas Sky Observatories
                                  MPC H45 - Petit Jean Mountain South
                                  MPC H41 - Petit Jean Mountain
                                  MPC H43 - Conway West
                                  http://www.arksky.org/

                                  ----- Original Message -----
                                   
                                  From:  P. Edward  Murray <mailto:ed1ward2@...>  

                                   
                                  To: comets-ml@yahoogroups.com
                                   
                                  Sent: Wednesday, October 09, 2013 1:38  PM
                                   
                                  Subject: Re: [comets-ml] COMET ISON:  ORANGE ALERT
                                   

                                   
                                   
                                   
                                   
                                   
                                   
                                   How long does it take between "Leveling off" as you say and when  the comet breaks apart?
                                   
                                   
                                   
                                  Ed Murray
                                   
                                  BMAA, Inc
                                   
                                  On 10/09/13,  ferrin@... wrote:
                                   
                                   
                                     
                                   
                                   
                                   

                                   

                                   
                                  Hi all:
                                   
                                  I have placed comet ISON in ORANGE ALERT.
                                   
                                  The reason?  The secular light curve is showing
                                   
                                  signs of leveling off:   
                                   

                                   
                                  http://astronomia.u dea.edu.co/cometspage
                                   

                                   
                                  In the past, with comets
                                  LINEAR,  Tabur, Honig and

                                  Elenin, just after the leveling off, the comet

                                  disintegrated.


                                   
                                  WE NEED URGENT CONFIRMATION OF THIS TREND
                                   

                                   
                                  I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                                   
                                  TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                                   

                                   
                                  respuestas2013 at gmail.com
                                   

                                   
                                  as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                                   
                                  SEND YOUR *SERIES*.  Use a simple .txt format
                                   

                                   
                                  YEAR MONTH DAY MAGNITUDE
                                   

                                   
                                  The first time you do specify the instrument aperture, band
                                   
                                  and type.   
                                  If you do  that:


                                   
                                  a) you will make my life easier.
                                   
                                  b) I will be able to update the light curve daily
                                   
                                  c) you will appear in the light curve
                                   
                                  d) you will help define the trend
                                   

                                   
                                  I have  evidence to conclude

                                  that the comet is  shedding off large particles,  as

                                  large as 1 cm or even larger.    If you look at the

                                  images, there are no filaments, there are  no

                                  streamers, just a diffuse light consistent  with a

                                  dust tail.


                                   
                                   
                                  Accordingly light from
                                  the continuu m  would dominate

                                  over the gas.


                                   
                                   
                                  Could anybody take a spectrum
                                  of the  comet in the

                                  visual and publish it as soon as possible ?

                                  Can anybody confirm or deny this  ?


                                   
                                  Kind regards,
                                   
                                  Ignacio

                                  Institute of Physics

                                  University of Antioquia

                                  oooooooooooooooooooooooooooooooooooo

                                   

                                     




                                  From the Desk of
                                  Daniel Andrew Janosick



                                • skyweek
                                  ... Just calculating the Roche radius is *way* too simplified an approach to comet nucleus survival prediction as http://arxiv.org/abs/1309.2288 - now also
                                  Message 16 of 26 , Oct 10, 2013
                                    > The comet would disintegrate due to tidal forces once inside the solar
                                    > Roche's limit about 3 solar radii

                                    Just calculating the Roche radius is *way* too simplified an approach to
                                    comet nucleus survival prediction as http://arxiv.org/abs/1309.2288 - now
                                    also summarized in http://www.swri.org/9what/releases/2013/ison.htm and
                                    http://www.nature.com/news/comet-expected-to-survive-close-sun-encounter-1.13924
                                    - have shown. The paper is pretty long and detailled but well worth your
                                    time.

                                    Daniel
                                  • Jean Meeus
                                    In astronomy, the word secular refers to a long period, one century or more. Example: the secular variations of the planetary orbits. But why does Ferrin
                                    Message 17 of 26 , Oct 10, 2013
                                      In astronomy, the word "secular" refers to a long period, one century or more.
                                      Example: the secular variations of the planetary orbits.
                                      But why does Ferrin speak of a "secular" light curve of comet ISON, an object
                                      that has been observed during only 12 months? It is simply a light curve,
                                      not a "secular" light curve. The latter is rather odd, to say the least...

                                      Jean Meeus



                                      On 10 October 2013 17:55, Juan Lacruz <juan@...> wrote:
                                       

                                      The comet would disintegrate due to tidal forces once inside the solar Roche's limit about 3 solar radii, now it is far outside this region.
                                      Juan 


                                      On Thu, Oct 10, 2013 at 2:06 PM, <stargazer_08121961@...> wrote:
                                       

                                      It does seem hard to figure ISON out.  From the images, it seems to be developing just fine, but perhaps if we had as good imagery of some of the other disintegrated comets, they would have looked good as well.  On the other hand, it seems to that the slope of its brightening is little different from an ordinary reflective body with no cometary activity.  This is not good at all.  Those of us who pray should hope that the it follows a "religious" light curve rather than a "secular" one. 



                                      ---In comets-ml@yahoogroups.com, <comets-ml@yahoogroups.com> wrote:

                                      < I have placed comet ISON in ORANGE ALERT.
                                      < The reason?  The secular light curve is showing signs of leveling off:   

                                      Why do you call it a "secular" light curve? 
                                      The word "secular" comes from the Latin "seculus" which means century.

                                      Jean Meeus



                                      On 9 October 2013 21:57, Daniel Janosick <danjanos@...> wrote:
                                       

                                      Dr. Clay,
                                         I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on   beyond speculation to a point of... Well like you said just plain silliness. But one thing is for sure, this is EXCITING.

                                      Dan



                                      On 10/9/13 3:49 PM, "P. Clay Sherrod" <drclay@...> wrote:


                                       
                                       
                                         


                                      "Orange Alert?"
                                      I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                                       
                                      Clay
                                      _____
                                      Dr. P. Clay Sherrod
                                      Arkansas Sky Observatories
                                      MPC H45 - Petit Jean Mountain South
                                      MPC H41 - Petit Jean Mountain
                                      MPC H43 - Conway West
                                      http://www.arksky.org/

                                      ----- Original Message -----
                                       
                                      From:  P. Edward  Murray <mailto:ed1ward2@...>  

                                       
                                      To: comets-ml@yahoogroups.com
                                       
                                      Sent: Wednesday, October 09, 2013 1:38  PM
                                       
                                      Subject: Re: [comets-ml] COMET ISON:  ORANGE ALERT
                                       

                                       
                                       
                                       
                                       
                                       
                                       
                                       How long does it take between "Leveling off" as you say and when  the comet breaks apart?
                                       
                                       
                                       
                                      Ed Murray
                                       
                                      BMAA, Inc
                                       
                                      On 10/09/13,  ferrin@... wrote:
                                       
                                       
                                         
                                       
                                       
                                       

                                       

                                       
                                      Hi all:
                                       
                                      I have placed comet ISON in ORANGE ALERT.
                                       
                                      The reason?  The secular light curve is showing
                                       
                                      signs of leveling off:   
                                       

                                       
                                      http://astronomia.u dea.edu.co/cometspage
                                       

                                       
                                      In the past, with comets
                                      LINEAR,  Tabur, Honig and

                                      Elenin, just after the leveling off, the comet

                                      disintegrated.


                                       
                                      WE NEED URGENT CONFIRMATION OF THIS TREND
                                       

                                       
                                      I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                                       
                                      TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                                       

                                       
                                      respuestas2013 at gmail.com
                                       

                                       
                                      as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                                       
                                      SEND YOUR *SERIES*.  Use a simple .txt format
                                       

                                       
                                      YEAR MONTH DAY MAGNITUDE
                                       

                                       
                                      The first time you do specify the instrument aperture, band
                                       
                                      and type.   
                                      If you do  that:


                                       
                                      a) you will make my life easier.
                                       
                                      b) I will be able to update the light curve daily
                                       
                                      c) you will appear in the light curve
                                       
                                      d) you will help define the trend
                                       

                                       
                                      I have  evidence to conclude

                                      that the comet is  shedding off large particles,  as

                                      large as 1 cm or even larger.    If you look at the

                                      images, there are no filaments, there are  no

                                      streamers, just a diffuse light consistent  with a

                                      dust tail.


                                       
                                       
                                      Accordingly light from
                                      the continuu m  would dominate

                                      over the gas.


                                       
                                       
                                      Could anybody take a spectrum
                                      of the  comet in the

                                      visual and publish it as soon as possible ?

                                      Can anybody confirm or deny this  ?


                                       
                                      Kind regards,
                                       
                                      Ignacio

                                      Institute of Physics

                                      University of Antioquia

                                      oooooooooooooooooooooooooooooooooooo

                                       

                                         




                                      From the Desk of
                                      Daniel Andrew Janosick




                                    • Alan Hale
                                      Hello everyone, Partially inspired by a post from Terry L. that I saw on Facebook, I ve expanded my calculations from yesterday s post. I ve looked at a number
                                      Message 18 of 26 , Oct 10, 2013
                                        Hello everyone,

                                        Partially inspired by a post from Terry L. that I saw on Facebook, I've expanded my calculations from yesterday's post. I've looked at a number of recent small-q comets that were borderline in terms of being bright enough intrinsically to survive perihelion, to compare with my brightness measurement yesterday morning of ISON. 

                                        There are two parts to this.

                                        First, those comets which I was observing at, or at least sometime around, the time when they were at the same heliocentric distance that ISON was yesterday (1.487 AU).  They are listed below, with columns giving: comet, perihelion distance (AU), heliocentric magnitude (observed magnitude corrected for geocentric distance using 5 log Delta, i.e., inverse square law), and whether or not the comet survived. All of this is based upon my own observations, with the exception of C/2011 L4, which I discussed yesterday. I'd place formal uncertainties at around +/- 0.3 magnitude.

                                        C/2012 S1      0.012     9.7         we'll see!
                                        C/2011 L4      0.302     6.8         yes
                                        C/2010 X1      0.483   11.9        no (remnant of tail survived)
                                        C/2009 R1      0.405     8.9        no (remnant survived in SWAN images for a while)
                                        C/2006 P1      0.171     7.7         yes
                                        C/2002 V1      0.099  10.2         yes  (not an Oort Cloud comet)
                                        C/1999 S4      0.765     9.9         no
                                        C/1996 Q1     0.840     9.1         no  (not an Oort Cloud comet; fragment of C/1988 A1)
                                        C/1991 X2      0.199   12.2         no


                                        Now, those comets which I was not observing at the time in question, in most cases because they hadn't been discovered yet. Here I give heliocentric H_10 absolute magnitudes for the time I first observed them (except for ISON, where again I'm referring to my observation yesterday morning). Columns are: comet, perihelion distance in AU, heliocentric distance (AU) where I first observed it, heliocentric H_10 absolute magnitude at that distance, and whether or not the comet survived. I have two values for C/2012 T5; the first was when I made my first unsuccessful attempt, the second when I saw it after the outburst that was well documented. (I actually saw the comet a few nights before this, but that was in bright moonlight, and I don't really trust my brightness measurement then.)

                                        C/2012 S1      0.012      1.487     8.0       we'll see!
                                        C/2012 T5      0.323      1.251  [13.1:    no  (pre-outburst)
                                        C/2012 T5      0.323      0.730   12.4      no (post-outburst)
                                        C/2004 R2      0.113      0.926   11.4      no
                                        C/2002 X5      0.190      1.220      7.4     yes
                                        C/2002 O6     0.495      1.003    11.9     no (observation made under less-than-ideal conditions; possibly not an Oort Cloud comet)
                                        C/2002 O4     0.776      1.388      9.3     no
                                        C/2000 W1    0.321      0.613    10.2     yes
                                        C/1988 P1      0.165      1.125      8.1     no
                                        C/1987 W1    0.200      1.246    10.0     no
                                        C/1985 K1      0.106      0.996      8.5     no  (very faint remnant photographed two months after perihelion)


                                        Of course, this is based upon a single data point for Comet ISON, and a single data point for each of the other comets, so any conclusions should be taken for what they're worth. 


                                        To address Chris' question: a star in the coma does make this tricky, even if the star is fainter than the comet's overall total magnitude; the point source is still brighter than the surface brightness of the surrounding coma. Plus, if one is defocusing things a bit (like in the Morris method, which I often use), the defocused star contributes to the coma brightness. I'll sometimes see if I can mentally subtract the star's contribution, but that's a pretty "iffy" process; usually when I encounter such conditions, I'll just place a colon by the brightness measurement — and try to observe the comet again later when there aren't any stars within the coma! (Sometimes easier said than done, of course.)

                                        Sincerely,

                                        Alan
                                      • Jakub Cerny
                                        Hi Alan, interesting analysis. Just note, C/1999 S4 was not an Oort cloud comet either. Best regards, Jakub Cerny
                                        Message 19 of 26 , Oct 10, 2013
                                          Hi Alan,

                                          interesting analysis.
                                          Just note, C/1999 S4 was not an Oort cloud comet either.

                                          Best regards,
                                          Jakub Cerny

                                          On 10/10/2013 09:55 PM, Alan Hale wrote:
                                           
                                          Hello everyone,

                                          Partially inspired by a post from Terry L. that I saw on Facebook, I've expanded my calculations from yesterday's post. I've looked at a number of recent small-q comets that were borderline in terms of being bright enough intrinsically to survive perihelion, to compare with my brightness measurement yesterday morning of ISON. 

                                          There are two parts to this.

                                          First, those comets which I was observing at, or at least sometime around, the time when they were at the same heliocentric distance that ISON was yesterday (1.487 AU).  They are listed below, with columns giving: comet, perihelion distance (AU), heliocentric magnitude (observed magnitude corrected for geocentric distance using 5 log Delta, i.e., inverse square law), and whether or not the comet survived. All of this is based upon my own observations, with the exception of C/2011 L4, which I discussed yesterday. I'd place formal uncertainties at around +/- 0.3 magnitude.

                                          C/2012 S1      0.012     9.7         we'll see!
                                          C/2011 L4      0.302     6.8         yes
                                          C/2010 X1      0.483   11.9        no (remnant of tail survived)
                                          C/2009 R1      0.405     8.9        no (remnant survived in SWAN images for a while)
                                          C/2006 P1      0.171     7.7         yes
                                          C/2002 V1      0.099  10.2         yes  (not an Oort Cloud comet)
                                          C/1999 S4      0.765     9.9         no
                                          C/1996 Q1     0.840     9.1         no  (not an Oort Cloud comet; fragment of C/1988 A1)
                                          C/1991 X2      0.199   12.2         no


                                          Now, those comets which I was not observing at the time in question, in most cases because they hadn't been discovered yet. Here I give heliocentric H_10 absolute magnitudes for the time I first observed them (except for ISON, where again I'm referring to my observation yesterda y morning). Columns are: comet, perihelion distance in AU, heliocentric distance (AU) where I first observed it, heliocentric H_10 absolute magnitude at that distance, and whether or not the comet survived. I have two values for C/2012 T5; the first was when I made my first unsuccessful attempt, the second when I saw it after the outburst that was well documented. (I actually saw the comet a few nights before this, but that was in bright moonlight, and I don't really trust my brightness measurement then.)

                                          C/2012 S1      0.012      1.487     8.0       we'll see!
                                          C/2012 T5      0.323      1.251  [13.1:    no  (pre-outburst)
                                          C/2012 T5      0.323      0.730   12.4       ;no (post-outburst)
                                          C/2004 R2      0.113      0.926   11.4      no
                                          C/2002 X5      0.190      1.220      7.4     yes
                                          C/2002 O6     0.495      1.003    11.9     no (observation made under less-than-ideal conditions; possibly not an Oort Cloud comet)
                                          C/2002 O4     0.776      1.388      9.3     no
                                          C/2000 W1    0.321      0.613    10.2     yes
                                          C/1988 P1      0.165      1.125      8.1     no
                                          C/1987 W1    0.20 0      1.246    10.0     no
                                          C/1985 K1      0.106      0.996      8.5     no  (very faint remnant photographed two months after perihelion)


                                          Of course, this is based upon a single data point for Comet ISON, and a single data point for each of the other comets, so any conclusions should be taken for what they're worth. 


                                          To address Chris' question: a star in the coma does make this tricky, even if the star is fainter than the comet's overall total magnitude; the point source is still brighter than the surface brightness of the surrounding coma. Plus, if one is defocusing things a bit (like in the Morris method, which I often use), the defocused star contributes to the coma brightness. I'll sometimes see if I can mentally subtract the star's contribution, but that's a pretty "iffy" process; usually when I encounter such conditions, I'll just place a colon by the brightness measurement — and try to observe the comet again later when there aren't any stars within the coma! (Sometimes easier said than done, of course.)

                                          Sincerely,

                                          Alan

                                        • Alan Hale
                                          Dear Jakub, Do you (or anyone else) have a pertinent calculation for C/1999 S4? The comet orbit catalogue does not give a (1/a)_orig, just a (1/a)_osc, which,
                                          Message 20 of 26 , Oct 10, 2013
                                            Dear Jakub,

                                            Do you (or anyone else) have a pertinent calculation for C/1999 S4? The comet orbit catalogue does not give a (1/a)_orig, just a (1/a)_osc, which, taken at face value, is indeed indicative of not being an Oort Cloud comet.

                                            For what it's worth, Zdenek Sekanina speculated at the time that C/1999 S4 might have been a trailing fragment of a larger comet (IAUC 7471).


                                            Sincerely,

                                            Alan
                                          • Jakub Cerny
                                            Dear Alan, Sekanina is taking that from source Marsden, B. G. (2000). Comet C/1999 S4 (LINEAR). Minor Plan. Circ. 40988 Unfortunatelly I fail to find it.
                                            Message 21 of 26 , Oct 10, 2013
                                              Dear Alan,

                                              Sekanina is taking that from source Marsden, B. G. (2000). Comet C/1999 S4 (LINEAR). Minor Plan. Circ. 40988

                                              Unfortunatelly I fail to find it.

                                              However, original 1/a also indepently calculating Kinoshita, see his web:
                                              http://jcometobs.web.fc2.com/year/r2000.htm

                                              He calculated original 1/a +0.000694 which means a = 1440 AU and period ~55 000 years.

                                              Best regards,
                                              Jakub Cerny

                                              On 10/10/2013 11:41 PM, Alan Hale wrote:
                                               
                                              Dear Jakub,

                                              Do you (or anyone else) have a pertinent calculation for C/1999 S4? The comet orbit catalogue does not give a (1/a)_orig, just a (1/a)_osc, which, taken at face value, is indeed indicative of not being an Oort Cloud comet.

                                              For what it's worth, Zdenek Sekanina speculated at the time that C/1999 S4 might have been a trailing fragment of a larger comet (IAUC 7471).


                                              Sincerely,

                                              Alan

                                            • Alan Hale
                                              Dear Jakub, The 1/a value of +0.000694 in Kinoshita s table refers to (1/a)_osc. His (1/a)_orig is +0.000002, which is definitely that of an Oort Cloud comet.
                                              Message 22 of 26 , Oct 10, 2013
                                                Dear Jakub,

                                                The 1/a value of +0.000694 in Kinoshita's table refers to (1/a)_osc. His (1/a)_orig is +0.000002, which is definitely that of an Oort Cloud comet.

                                                Sekanina's reference to Marsden's work is MPEC 2000-O07 and the large non-gravitational forces that he determined for this comet. Following from a post you made earlier, this would suggest a small nucleus — so perhaps no surprise that it disintegrated.

                                                Incidentally, you can find the MPC you referenced at http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2000/MPC_20000726.pdf


                                                Sincerely,

                                                Alan

                                              • Jakub Cerny
                                                You are correct, I misread his format lines. Jakub
                                                Message 23 of 26 , Oct 10, 2013
                                                  You are correct, I misread his format lines.

                                                  Jakub

                                                  On 10/11/2013 01:08 AM, Alan Hale wrote:
                                                   
                                                  Dear Jakub,

                                                  The 1/a value of +0.000694 in Kinoshita's table refers to (1/a)_osc. His (1/a)_orig is +0.000002, which is definitely that of an Oort Cloud comet.

                                                  Sekanina's reference to Marsden's work is MPEC 2000-O07 and the large non-gravitational forces that he determined for this comet. Following from a post you made earlier, this would suggest a small nucleus — so perhaps no surprise that it disintegrated.

                                                  Incidentally, you can find the MPC you referenced at http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2000/MPC_20000726.pdf


                                                  Sincerely,

                                                  Alan


                                                • jim_scotti
                                                  I m pretty sure that Ferrin uses Secular to differentiate his light curve from a diurnal or rotational light curve. It is the long term light curve in this
                                                  Message 24 of 26 , Oct 10, 2013

                                                    I'm pretty sure that Ferrin uses Secular to differentiate his light curve from a diurnal or rotational light curve.  It is the long term light curve in this case. 


                                                    Jim Scotti



                                                    ---In comets-ml@yahoogroups.com, <comets-ml@yahoogroups.com> wrote:

                                                    In astronomy, the word "secular" refers to a long period, one century or more.
                                                    Example: the secular variations of the planetary orbits.
                                                    But why does Ferrin speak of a "secular" light curve of comet ISON, an object
                                                    that has been observed during only 12 months? It is simply a light curve,
                                                    not a "secular" light curve. The latter is rather odd, to say the least...

                                                    Jean Meeus



                                                    On 10 October 2013 17:55, Juan Lacruz <juan@...> wrote:
                                                     
                                                    The comet would disintegrate due to tidal forces once inside the solar Roche's limit about 3 solar radii, now it is far outside this region.
                                                    Juan 


                                                    On Thu, Oct 10, 2013 at 2:06 PM, <stargazer_08121961@...> wrote:
                                                     

                                                    It does seem hard to figure ISON out.  From the images, it seems to be developing just fine, but perhaps if we had as good imagery of some of the other disintegrated comets, they would have looked good as well.  On the other hand, it seems to that the slope of its brightening is little different from an ordinary reflective body with no cometary activity.  This is not good at all.  Those of us who pray should hope that the it follows a "religious" light curve rather than a "secular" one. 



                                                    ---In comets-ml@yahoogroups.com, <comets-ml@yahoogroups.com> wrote:

                                                    < I have placed comet ISON in ORANGE ALERT.
                                                    < The reason?  The secular light curve is showing signs of leveling off:   

                                                    Why do you call it a "secular" light curve? 
                                                    The word "secular" comes from the Latin "seculus" which means century.

                                                    Jean Meeus



                                                    On 9 October 2013 21:57, Daniel Janosick <danjanos@...> wrote:
                                                     

                                                    Dr. Clay,
                                                       I am am amateur astronomer and love the hobby and this sub segment. But some of the posts in the group are bordering, on   beyond speculation to a point of... Well like you said just plain silliness. But one thing is for sure, this is EXCITING.

                                                    Dan



                                                    On 10/9/13 3:49 PM, "P. Clay Sherrod" <drclay@...> wrote:


                                                     
                                                     
                                                       


                                                    "Orange Alert?"
                                                    I think this is entering the realm of silliness at this point.  There is absolutely no evidence that ISON is breaking up.
                                                     
                                                    Clay
                                                    _____
                                                    Dr. P. Clay Sherrod
                                                    Arkansas Sky Observatories
                                                    MPC H45 - Petit Jean Mountain South
                                                    MPC H41 - Petit Jean Mountain
                                                    MPC H43 - Conway West
                                                    http://www.arksky.org/

                                                    ----- Original Message -----
                                                     
                                                    From:  P. Edward  Murray <mailto:ed1ward2@...>  

                                                     
                                                    To: comets-ml@yahoogroups.com
                                                     
                                                    Sent: Wednesday, October 09, 2013 1:38  PM
                                                     
                                                    Subject: Re: [comets-ml] COMET ISON:  ORANGE ALERT
                                                     

                                                     
                                                     
                                                     
                                                     
                                                     
                                                     
                                                     How long does it take between "Leveling off" as you say and when  the comet breaks apart?
                                                     
                                                     
                                                     
                                                    Ed Murray
                                                     
                                                    BMAA, Inc
                                                     
                                                    On 10/09/13,  ferrin@... wrote:
                                                     
                                                     
                                                       
                                                     
                                                     
                                                     

                                                     

                                                     
                                                    Hi all:
                                                     
                                                    I have placed comet ISON in ORANGE ALERT.
                                                     
                                                    The reason?  The secular light curve is showing
                                                     
                                                    signs of leveling off:   
                                                     

                                                     
                                                    http://astronomia.u dea.edu.co/cometspage
                                                     

                                                     
                                                    In the past, with comets
                                                    LINEAR,  Tabur, Honig and

                                                    Elenin, just after the leveling off, the comet

                                                    disintegrated.


                                                     
                                                    WE NEED URGENT CONFIRMATION OF THIS TREND
                                                     

                                                     
                                                    I REQUEST TO CCD-R, CCD-V AND VISUAL OBSERVERS
                                                     
                                                    TO SEND THEIR *SERIES* OF OBSERVATIONS TO ME AT
                                                     

                                                     
                                                    respuestas2013 at gmail.com
                                                     

                                                     
                                                    as soon as possible.  DO NOT SEND ISOLATED OBSERVATIONS.
                                                     
                                                    SEND YOUR *SERIES*.  Use a simple .txt format
                                                     

                                                     
                                                    YEAR MONTH DAY MAGNITUDE
                                                     

                                                     
                                                    The first time you do specify the instrument aperture, band
                                                     
                                                    and type.   
                                                    If you do  that:


                                                     
                                                    a) you will make my life easier.
                                                     
                                                    b) I will be able to update the light curve daily
                                                     
                                                    c) you will appear in the light curve
                                                     
                                                    d) you will help define the trend
                                                     

                                                     
                                                    I have  evidence to conclude

                                                    that the comet is  shedding off large particles,  as

                                                    large as 1 cm or even larger.    If you look at the

                                                    images, there are no filaments, there are  no

                                                    streamers, just a diffuse light consistent  with a

                                                    dust tail.


                                                     
                                                     
                                                    Accordingly light from
                                                    the continuu m  would dominate

                                                    over the gas.


                                                     
                                                     
                                                    Could anybody take a spectrum
                                                    of the  comet in the

                                                    visual and publish it as soon as possible ?

                                                    Can anybody confirm or deny this  ?


                                                     
                                                    Kind regards,
                                                     
                                                    Ignacio

                                                    Institute of Physics

                                                    University of Antioquia

                                                    oooooooooooooooooooooooooooooooooooo

                                                     

                                                       




                                                    From the Desk of
                                                    Daniel Andrew Janosick




                                                  • grunwalder2002
                                                    http://www.minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&object_id=C%2F1999+S4 displays both original and future 1/a values. Go to:
                                                    Message 25 of 26 , Oct 10, 2013

                                                       http://www.minorplanetcenter.net/db_search/show_object?utf8=%E2%9C%93&object_id=C%2F1999+S4


                                                      displays both original and future 1/a values.  Go to:


                                                      http://www.minorplanetcenter.net/db_search


                                                      is you want the same info for a different object.



                                                      ---In comets-ml@yahoogroups.com, <ahale@...> wrote:

                                                      Dear Jakub,

                                                      Do you (or anyone else) have a pertinent calculation for C/1999 S4? The comet orbit catalogue does not give a (1/a)_orig, just a (1/a)_osc, which, taken at face value, is indeed indicative of not being an Oort Cloud comet.

                                                      For what it's worth, Zdenek Sekanina speculated at the time that C/1999 S4 might have been a trailing fragment of a larger comet (IAUC 7471).


                                                      Sincerely,

                                                      Alan
                                                    • Jakub Cerny
                                                      Hello Alan, I have an answer from Z. Sekanina. The statement about comet C/1999 S4 (LINEAR) was unclear. But I got told that original orbit of this comet can t
                                                      Message 26 of 26 , Oct 14, 2013
                                                        Hello Alan,

                                                        I have an answer from Z. Sekanina. The statement about comet C/1999 S4 (LINEAR) was unclear. But I got told that original orbit of this comet can't be calculated because of strong non-gravitional parameters. They should result into large scatter and errorneous results of original 1/a depending on kind of non-gravitional law used for calculation. Because of that, Marsden never calculated original 1/a value. Origin of comet from Oort cloud is therefore discutabile.

                                                        Best regards,
                                                        Jakub Cerny

                                                        On 10/11/2013 01:08 AM, Alan Hale wrote:
                                                         
                                                        Dear Jakub,

                                                        The 1/a value of +0.000694 in Kinoshita's table refers to (1/a)_osc. His (1/a)_orig is +0.000002, which is definitely that of an Oort Cloud comet.

                                                        Sekanina's reference to Marsden's work is MPEC 2000-O07 and the large non-gravitational forces that he determined for this comet. Following from a post you made earlier, this would suggest a small nucleus — so perhaps no surprise that it disintegrated.

                                                        Incidentally, you can find the MPC you referenced at http://www.minorplanetcenter.net/iau/ECS/MPCArchive/2000/MPC_20000726.pdf


                                                        Sincerely,

                                                        Alan


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