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Re: C/2010 X1 (Elenin) visually observable at m1=14.9.

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  • chergen
    ... I d like to second John s statement. Based on CCD magnitude estimates by Artyom, Giovanni and myself, this comet is intrinsically faint. Unless the comet
    Message 1 of 28 , Apr 6, 2011
      > I would also like to point out that the current photometric
      > parameters for C/2010 X1 suggest to me that the comet may
      > be intrinsically a bit too faint to even survive perihelion
      > passage.

      I'd like to second John's statement. Based on CCD magnitude
      estimates by Artyom, Giovanni and myself, this comet is
      intrinsically faint. Unless the comet brightens much faster
      than 10log(r), it is a candidate to fizzle or disappear. That's
      not a given though and much fainter comets have survived.

      Take a look at the below graph which compares the current and
      forecast brightness of C/2010 X1 with the perihelion
      brightnesses of a number of other long-period comets, including
      some fizzlers.

      http://transientsky.wordpress.com/c2010-x1

      Right now it is hard to tell how fast X1 is brightening. It is
      obvious that the comet experienced a significant apparent
      brightening due to back scattering when it went through
      opposition (phase angle dropped to an amazing 0.4 deg). We may
      have to get another month or two past opposition for the real
      trend to reestablish itself. Still a 10log(r) brightening rate
      is possible.

      Based solely on the CCD data it doesn't matter if the comet
      brightens at 10log(r) or 8log(r), the comet will have an
      absolute brightness at perihelion that gives it a ~50-50 chance
      of surviving this trip around the Sun. For comparison, the
      current brightness of C/2011 C1 is also plotted which shows that
      comet to be intrinsically brighter than X1.

      If we add in the the 2 recent visual estimates by J.J. and
      Jakub it would suggest a comet that has a much better chance
      of avoiding a disrupted state.

      Unlike others, I like when comets fizzle. I actually have my
      fingers crossed that this comet will survive perihelion and then
      fizzle when close to Earth, and well placed for observation, in
      October. It will then be an easy target for some of the biggest
      scopes in the world. Sometimes we learn more about comets when
      they fall apart.

      Regardless, fizzler or not, the super low phase angle at
      opposition, the high phase angle at perihelion and close
      approach to Earth post-perihelion makes this a comet to watch.
      (As if we weren't going to anyway.)

      - Carl Hergenrother
    • RICHARD MILES
      ... OBJECT DATE TIME 10x10 20x20 30x30 40x40 50x50 60x60 SNR SBB COD ... C/2010 X1 31/03/2011 20:55:01 16.60 15.96 15.77
      Message 2 of 28 , Apr 6, 2011
        >> I would also like to point out that the current photometric
        >> parameters for C/2010 X1 suggest to me that the comet may
        >> be intrinsically a bit too faint to even survive perihelion
        >> passage.


        OBJECT DATE TIME 10x10 20x20 30x30 40x40 50x50 60x60
        SNR SBB COD
        ------------ ---------- -------- ----- ----- ----- ----- ----- -----
        ---- ---- ---
        C/2010 X1 31/03/2011 20:55:01 16.60 15.96 15.77 15.72 15.68 15.71
        6.2 17.0 213
        C/2010 X1 31/03/2011 23:19:07 16.60 15.99 15.76 15.60 15.50 15.37
        13.4 19.7 J38
        C/2010 X1 31/03/2011 23:56:23 16.52 15.85 15.49 15.20 14.95 14.72
        11.1 19.1 945
        C/2010 X1 01/04/2011 22:51:55 16.51 15.94 15.81 15.67 15.61 15.49
        8.1 18.9 939
        C/2010 X1 03/04/2011 00:10:43 16.53 15.96 15.82 15.64 15.46 15.44
        5.5 18.5 B82
        C/2010 X1 03/04/2011 23:39:28 16.55 15.93 15.70 15.55 15.43 15.30
        13.6 20.0 J38
        C/2010 X1 04/04/2011 00:06:21 16.43 15.76 15.38 15.09 14.82 14.58
        9.6 19.2 945
        C/2010 X1 05/04/2011 00:04:26 16.39 15.73 15.39 15.12 14.85 14.60
        8.6 19.1 945

        I've just taken 30 x 60-sec V-filter images of C/2010 X1 from J77 analysis
        of which indicates the comet is significantly fainter than it was reported
        to be 48 hours ago.

        C/2010 X1 07/04/2011 00:33 V= 16.5 in a 38" diam. photometric aperture
        using a 10.5-cm refractor + CCD (1 pixel = 3.8")

        Can anyone else detect any fading?

        Richard Miles
        Golden Hill Obs., Dorset, UK
      • P. Clay Sherrod
        Your magnitude estimates were right on our values for April 6, at about m1=16.2, with m2=16.5, so very little difference between m1 and m2 via CCD. Clay _____
        Message 3 of 28 , Apr 6, 2011
          Your magnitude estimates were right on our values for April 6, at about m1=16.2, with
          m2=16.5, so very little difference between m1 and m2 via CCD.

          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: "RICHARD MILES" <rmiles.btee@...>
          To: <comets-ml@yahoogroups.com>
          Sent: Wednesday, April 06, 2011 8:36 PM
          Subject: Re: [comets-ml] Re: C/2010 X1 (Elenin) visually observable at m1=14.9.


          >>> I would also like to point out that the current photometric
          >>> parameters for C/2010 X1 suggest to me that the comet may
          >>> be intrinsically a bit too faint to even survive perihelion
          >>> passage.
          >
          >
          > OBJECT DATE TIME 10x10 20x20 30x30 40x40 50x50 60x60
          > SNR SBB COD
          > ------------ ---------- -------- ----- ----- ----- ----- ----- -----
          > ---- ---- ---
          > C/2010 X1 31/03/2011 20:55:01 16.60 15.96 15.77 15.72 15.68 15.71
          > 6.2 17.0 213
          > C/2010 X1 31/03/2011 23:19:07 16.60 15.99 15.76 15.60 15.50 15.37
          > 13.4 19.7 J38
          > C/2010 X1 31/03/2011 23:56:23 16.52 15.85 15.49 15.20 14.95 14.72
          > 11.1 19.1 945
          > C/2010 X1 01/04/2011 22:51:55 16.51 15.94 15.81 15.67 15.61 15.49
          > 8.1 18.9 939
          > C/2010 X1 03/04/2011 00:10:43 16.53 15.96 15.82 15.64 15.46 15.44
          > 5.5 18.5 B82
          > C/2010 X1 03/04/2011 23:39:28 16.55 15.93 15.70 15.55 15.43 15.30
          > 13.6 20.0 J38
          > C/2010 X1 04/04/2011 00:06:21 16.43 15.76 15.38 15.09 14.82 14.58
          > 9.6 19.2 945
          > C/2010 X1 05/04/2011 00:04:26 16.39 15.73 15.39 15.12 14.85 14.60
          > 8.6 19.1 945
          >
          > I've just taken 30 x 60-sec V-filter images of C/2010 X1 from J77 analysis
          > of which indicates the comet is significantly fainter than it was reported
          > to be 48 hours ago.
          >
          > C/2010 X1 07/04/2011 00:33 V= 16.5 in a 38" diam. photometric aperture
          > using a 10.5-cm refractor + CCD (1 pixel = 3.8")
          >
          > Can anyone else detect any fading?
          >
          > Richard Miles
          > Golden Hill Obs., Dorset, UK
          >
          >
          >
          > ------------------------------------
          >
          > Comet Observations List: http://groups.yahoo.com/group/CometObs/
          > Comet Images List: http://groups.yahoo.com/group/Comet-Images/
          >
          > NOTICE: Material quoted or re-posted from the Comets Mailing List should be indicated
          > by:
          >
          > Comets Mailing List [date]
          > http://www.yahoogroups.com/group/comets-ml
          > Yahoo! Groups Links
          >
          >
          >
          >
        • Artyom Novichonok
          Hello all! I updated my light curve for Elenin s comet: http://www.astronomy.ru/forum/index.php?action=dlattach;topic=80608.0;attach=301417;image I will take
          Message 4 of 28 , Apr 6, 2011
            Hello all!

            I updated my light curve for Elenin's comet:
            http://www.astronomy.ru/forum/index.php?action=dlattach;topic=80608.0;attach=301417;image

            I will take new CCD-estimates for the comet near time...

            Best regards,
            Artyom.
          • J.P.Navarro Pina
            The difference between CCD and visual magnitudes magnitudes dependent upon the degree of condensation of cometary coma when the comet is very condensed (GC =
            Message 5 of 28 , Apr 6, 2011
              The difference between CCD and visual magnitudes magnitudes dependent upon the degree of condensation of cometary coma when the comet is very condensed (GC = 9) almost stellar, there is almost no difference between visual and CCD magnitudes, but when the coma is diffuse ( GC = 3 for example) the difference between m1 (CCD)-m1 (visual) is greater than around ~ 1 magnitude or more.
              Displaying multiaperture photometry should apply the highest opening in this case 60 x 60 in order to approximate the visual magnitude.

              Regards , J. P.Navarro Pina



              ----- Original Message -----
              From: P. Clay Sherrod
              To: comets-ml@yahoogroups.com
              Sent: Thursday, April 07, 2011 7:36 AM
              Subject: Re: [comets-ml] Re: C/2010 X1 (Elenin) visually observable at m1=14.9.



              Your magnitude estimates were right on our values for April 6, at about m1=16.2, with
              m2=16.5, so very little difference between m1 and m2 via CCD.

              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: "RICHARD MILES" <rmiles.btee@...>
              To: <comets-ml@yahoogroups.com>
              Sent: Wednesday, April 06, 2011 8:36 PM
              Subject: Re: [comets-ml] Re: C/2010 X1 (Elenin) visually observable at m1=14.9.

              >>> I would also like to point out that the current photometric
              >>> parameters for C/2010 X1 suggest to me that the comet may
              >>> be intrinsically a bit too faint to even survive perihelion
              >>> passage.
              >
              >
              > OBJECT DATE TIME 10x10 20x20 30x30 40x40 50x50 60x60
              > SNR SBB COD
              > ------------ ---------- -------- ----- ----- ----- ----- ----- -----
              > ---- ---- ---
              > C/2010 X1 31/03/2011 20:55:01 16.60 15.96 15.77 15.72 15.68 15.71
              > 6.2 17.0 213
              > C/2010 X1 31/03/2011 23:19:07 16.60 15.99 15.76 15.60 15.50 15.37
              > 13.4 19.7 J38
              > C/2010 X1 31/03/2011 23:56:23 16.52 15.85 15.49 15.20 14.95 14.72
              > 11.1 19.1 945
              > C/2010 X1 01/04/2011 22:51:55 16.51 15.94 15.81 15.67 15.61 15.49
              > 8.1 18.9 939
              > C/2010 X1 03/04/2011 00:10:43 16.53 15.96 15.82 15.64 15.46 15.44
              > 5.5 18.5 B82
              > C/2010 X1 03/04/2011 23:39:28 16.55 15.93 15.70 15.55 15.43 15.30
              > 13.6 20.0 J38
              > C/2010 X1 04/04/2011 00:06:21 16.43 15.76 15.38 15.09 14.82 14.58
              > 9.6 19.2 945
              > C/2010 X1 05/04/2011 00:04:26 16.39 15.73 15.39 15.12 14.85 14.60
              > 8.6 19.1 945
              >
              > I've just taken 30 x 60-sec V-filter images of C/2010 X1 from J77 analysis
              > of which indicates the comet is significantly fainter than it was reported
              > to be 48 hours ago.
              >
              > C/2010 X1 07/04/2011 00:33 V= 16.5 in a 38" diam. photometric aperture
              > using a 10.5-cm refractor + CCD (1 pixel = 3.8")
              >
              > Can anyone else detect any fading?
              >
              > Richard Miles
              > Golden Hill Obs., Dorset, UK
              >
              >
              >
              > ------------------------------------
              >
              > Comet Observations List: http://groups.yahoo.com/group/CometObs/
              > Comet Images List: http://groups.yahoo.com/group/Comet-Images/
              >
              > NOTICE: Material quoted or re-posted from the Comets Mailing List should be indicated
              > by:
              >
              > Comets Mailing List [date]
              > http://www.yahoogroups.com/group/comets-ml
              > Yahoo! Groups Links
              >
              >
              >
              >






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            • jakub.koukal
              Hi all, here is a little coment to my visual estimate of X1. I have seen this comet only 33% of time and for me it´s only 33% positive observation. But Alan
              Message 6 of 28 , Apr 7, 2011
                Hi all,
                here is a little coment to my visual estimate of X1. I have seen this comet only 33% of time and for me it´s only 33% positive observation.

                But Alan wrote words about limiting magnitude for consistent comets (for example DC 7-8, i think) and for him its limiting magnitude 14,2-14,3 for these comets. But i see G2 with magnitude 14,0-14,2 in my 240 mm Newton, and i´m totally sure (and 103P with magnitude 13,9 and DC 1 too)...i know, "walking on the edge" or "ghost catching" is hazardous:-(

                I observing comets since 1996, but my primary research is observation of meteor showers (visually and video)...on this account i have much, much, much less magnitude estimates than Alan, JJ and others...


                Best regards
                Jakub
              • Cometas LIADA
                Hi We invite you to send his CCD photometries to be published in Morris Format in the database of LIADA Comets Section (http://cometas.liada.net) Reports:
                Message 7 of 28 , Apr 7, 2011
                  Hi
                  We invite you to send his CCD photometries to be published in "Morris
                  Format" in the database of LIADA Comets Section (http://cometas.liada.net)
                  Reports: cometas.liada@...
                  and his photographies (visit:
                  https://picasaweb.google.com/rastreadoresdecometas/FotosRecientesDeCometas#)
                  Cheers,
                  Luis.
                  _________________________________________
                  Luis Alberto Mansilla Salvo / COMETS WATCHERS
                  * The Iberoamerican Astronomical League *
                  Web: http://cometas.liada.net
                  Reports: cometas.liada@...
                  _________________________________________

                  -----Mensaje original-----
                  From: gvnn64@...
                  Sent: Wednesday, April 06, 2011 6:45 AM
                  To: comets-ml
                  Subject: Re: [comets-ml] C/2010 X1 (Elenin) visually observable at m1=14.9.

                  Dear Alan, J. J. and all.

                  > I took some CCD images of the comet about a week ago; from the exposure
                  > time
                  > it took to record the comet I would "guesstimate" its brightness somewhere
                  > around m1 ~15 - 15.5.

                  Probably even fainter.

                  We are continuing our follow-up about this comet. The last CCD photometry we
                  obtained yesterday, provides the following amounts:

                  C/2010 X1 (Elenin)
                  2011, Apr. 5.6; m1= 16.4 (Ru), m2= 17.0 (Ru)
                  ( near Moorook - Australlia, 0.15-m f/7.3 refractor + CCD, G. Sostero and E.
                  Guido).

                  The coma, about 22 arcsec in diameter, appears still pretty compact, with a
                  hint of elongation toward South-East; http://tinyurl.com/6cfqsgr

                  So, also according to our last measurements, C/2010 X1 brightness is still
                  well below expectations.

                  On the other hand, I read with interest the visual estimation of J. J.
                  Gonzalez, posted yesterday in this mailing-list. According to J.J., comet
                  Elenin is indeed about 1 magnitude fainther than the MPC ephemerids (however
                  not as much as the CCD measurements are telling us).

                  OK, we are used to find such diversity among CCD measurements and visual
                  estimations of comets (we discussed a lot about this topic in the past, and
                  I don't like to rise again such boring discussion). However.... this time
                  there is a significative difference. Actually what makes me a little
                  confused, is that normally such difference is found (and then justified) for
                  pretty diffused objects. In the current case of C/2010 X1, we are dealing
                  with an extremely compact coma, that shows nearly the same diameter in CCD
                  shots and visual observations. I suspect, either, that the different
                  spectral sensitivity of the eye and the CCD (filtered or not) could not
                  account (at least this time) for such a big difference among CCD
                  measurements and visual estimations.

                  Any clue about this?

                  Thanks,
                  Giovanni Sostero



                  ------------------------------------

                  Comet Observations List: http://groups.yahoo.com/group/CometObs/
                  Comet Images List: http://groups.yahoo.com/group/Comet-Images/

                  NOTICE: Material quoted or re-posted from the Comets Mailing List should be
                  indicated by:

                  Comets Mailing List [date]
                  http://www.yahoogroups.com/group/comets-ml
                  Yahoo! Groups Links
                • Artyom Novichonok
                  Hello all! C/2010 X1 (Elenin) 2011 Apr. 08.32 UT: m1=15.4, Dia.=0.9 ...46-cm P + CCD ...L. Elenin & A. Novichonok (remotely ISON-NM observatory, Mayhill, USA)
                  Message 8 of 28 , Apr 8, 2011
                    Hello all!

                    C/2010 X1 (Elenin)
                    2011 Apr. 08.32 UT: m1=15.4, Dia.=0.9' ...46-cm P + CCD ...L. Elenin
                    & A. Novichonok (remotely ISON-NM observatory, Mayhill, USA)

                    --
                    Best regards,
                    Artyom.

                    My comets light curves page:
                    http://severastro.narod.ru/sla/com/lc.htm
                  • Castell
                    Hello all! At the same time as the below CCD observation we tried to catch the comet visually with a 20” (50.8 cm) Dobsonain: C/2010 X1 (Elenin) 2011 Apr
                    Message 9 of 28 , Apr 11, 2011
                      Hello all!

                      At the same time as the below CCD observation we tried to catch the comet visually with a 20” (50.8 cm) Dobsonain:

                      C/2010 X1 (Elenin)
                      2011 Apr 8.84 UT: m1: [15.2 (assumed 0.3’ coma), 50,8 cm reflector, 312x
                      In the field stars below 15.5 are easily seen, with averted vision the limiting magnitude was around 16.5. Something was glimpsed at the position of the comet, but with similar uncertanity as 16.2-16.5 stars. If the comet is condensed, must be fainter than 15.5. I observed with Zoltan Toth, he confirmed the same result.

                      Best regards,

                      Sandor Szabo

                      From: Artyom Novichonok
                      Sent: Friday, April 08, 2011 9:01 PM
                      To: comets-ml@yahoogroups.com
                      Subject: Re: [comets-ml] C/2010 X1 (Elenin) visually observable at m1=14.9.


                      Hello all!

                      C/2010 X1 (Elenin)
                      2011 Apr. 08.32 UT: m1=15.4, Dia.=0.9' ...46-cm P + CCD ...L. Elenin
                      & A. Novichonok (remotely ISON-NM observatory, Mayhill, USA)

                      --
                      Best regards,
                      Artyom.

                      My comets light curves page:
                      http://severastro.narod.ru/sla/com/lc.htm





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