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Re: [comets-ml] Final Nakedeye Observation of 17P?

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  • Sorin Hotea
    Hello everyone ! John I can contradict you a little. Last night (Feb 10.83 UT) I saw the 17P/Holmes comet from somewhere 30 km east of my hometown (Sighetu
    Message 1 of 18 , Feb 11, 2008
      Hello everyone !

      John I can contradict you a little. Last night (Feb 10.83 UT) I saw the
      17P/Holmes comet from somewhere 30 km east of my hometown (Sighetu
      Marmatiei, Romania) and it was very easy to observe even without eyes
      adapted to the darkness. Actually I got down from my car and I saw it. It
      was a big round nebular patch with a diameter of more than 2 degrees and a
      possible magnitude of 4. I could be the sky condition. I was just passing by
      there and I stopped to see if that is a good observation place. I didn't
      have any instrument with me but the sky was awesome. A very obvious Milky
      Way was visible through Auriga, Monoceros and Canis Major till near horizon.
      I will probably choose that place for observation in the future. I think the
      17P/Holmes comet will be visible on good sky this month even with naked
      eyes. A good chance to try is during the total lunar eclipse in the night of
      20/21 february.

      Clear skies !

      Sorin Hotea


      [Non-text portions of this message have been removed]
    • Luca Buzzi
      Hi all, from our site (Schiaparelli Observatory, Italy, 1230 m.a.s.l.) the comet is completely invisible to the naked eye. In these days the weather is very
      Message 2 of 18 , Feb 11, 2008
        Hi all,
        from our site (Schiaparelli Observatory, Italy, 1230 m.a.s.l.) the comet is
        completely invisible to the naked eye.
        In these days the weather is very good here in northern Italy, and our NELM
        is around 5.5, 6 at best.
        To be honest, it was quite difficult even with a 20x125mm binoculars and I
        think, of course, that its vision from very dark
        skies is completely a different thing.

        Regards,
        Luca Buzzi
        # 204




        -----Messaggio originale-----
        Da: comets-ml@yahoogroups.com [mailto:comets-ml@yahoogroups.com]Per conto
        di Sorin Hotea
        Inviato: lunedi 11 febbraio 2008 9.38
        A: comets-ml@yahoogroups.com
        Oggetto: Re: [comets-ml] Final Nakedeye Observation of 17P?


        Hello everyone !

        John I can contradict you a little. Last night (Feb 10.83 UT) I saw the
        17P/Holmes comet from somewhere 30 km east of my hometown (Sighetu
        Marmatiei, Romania) and it was very easy to observe even without eyes
        adapted to the darkness. Actually I got down from my car and I saw it. It
        was a big round nebular patch with a diameter of more than 2 degrees and a
        possible magnitude of 4. I could be the sky condition. I was just passing
        by
        there and I stopped to see if that is a good observation place. I didn't
        have any instrument with me but the sky was awesome. A very obvious Milky
        Way was visible through Auriga, Monoceros and Canis Major till near
        horizon.
        I will probably choose that place for observation in the future. I think
        the
        17P/Holmes comet will be visible on good sky this month even with naked
        eyes. A good chance to try is during the total lunar eclipse in the night
        of
        20/21 february.

        Clear skies !

        Sorin Hotea

        [Non-text portions of this message have been removed]






        [Non-text portions of this message have been removed]
      • Kenneth Drake
        John, I tried and failed to see Holmes naked eye from my Bortle Class 4-5 skies 53 miles north of Houston under pristine skies last Thursday night (Feb. 7). I
        Message 3 of 18 , Feb 11, 2008
          John,

          I tried and failed to see Holmes naked eye from my Bortle Class 4-5
          skies 53 miles north of Houston under pristine skies last Thursday night
          (Feb. 7). I was hoping to compare the appearance with the view I had
          from near Ft. Griffin, Texas (Bortle Class 2-3) on Jan. 29 when it was
          very obvious naked eye. I had a similar experience as you - it appeared
          larger (~2 deg) than in 10x70 binos (1.5x1.2 deg). I thought it was at
          least a magnitude fainter than M31 so I do not agree with the 4th
          magnitude estimates I'm seeing.

          Kenneth Drake

          cnj999 wrote:
          >
          > I think I can say with some confidence that the sighting I made of
          > 17P/Holmes about half an hour ago (Feb. 11.01UT) will be my last,
          > barring some new outburst. The comet was at the extreme limit of
          > averted vision for me, in my typically less than perfectly dark skies.
          > It seemd to subtend roughly 2 degrees and was essentially circular in
          > outline. At the same time, 15x70 binoculars still rather easily showed
          > the comet, although not to the full diameter evident with the unaided
          > eye.
          >
          > >From here on, the waxing moon will likely hide the comet from the view
          > of most, until at least Fenruary 22nd, by which time I would not expect
          > it to be detectable with the nakedeye any longer, even under the best
          > of skies.
          >
          > I'd certainly be interested in hearing how others are faring at this
          > point, especially without optical aid. 17P has certainly put on one
          > heck of a show...one of the most menorable in my 50+ years of comet
          > observing.
          >
          > JBortle
          >
          >
        • Bob King
          Hi John and friends, I m just about ready to agree with you about how faint 17P/Holmes has become. I observed it last night Feb. 11.1 UT from a very dark sky
          Message 4 of 18 , Feb 11, 2008
            Hi John and friends,
            I'm just about ready to agree with you about how faint 17P/Holmes has
            become. I observed it last night Feb. 11.1 UT from a very dark sky
            site. Certainly if you didn't know within a few degrees of where to
            look, you'd never notice it. Once spotted, averted vision helped keep
            it steadily in view. The comet was easy fare in 10x50 binoculars
            appearing like a foggy patch 2 degrees across. I was surprised to
            still be able to see the complete outline of the extended coma in my
            37cm reflector at 64x. Funny thing though of late. Every time I center
            17P in my finder and then look in the eyepiece, at first glance there
            appears to be nothing there at all! After careful sweeping, the comet
            magically reappears and assumes its regular form.
            Bob

            On Feb 10, 2008 6:59 PM, cnj999 <jbortle@...> wrote:
            >
            >
            >
            >
            >
            >
            > I think I can say with some confidence that the sighting I made of
            > 17P/Holmes about half an hour ago (Feb. 11.01UT) will be my last,
            > barring some new outburst. The comet was at the extreme limit of
            > averted vision for me, in my typically less than perfectly dark skies.
            > It seemd to subtend roughly 2 degrees and was essentially circular in
            > outline. At the same time, 15x70 binoculars still rather easily showed
            > the comet, although not to the full diameter evident with the unaided
            > eye.
            >
            > From here on, the waxing moon will likely hide the comet from the view
            > of most, until at least Fenruary 22nd, by which time I would not expect
            > it to be detectable with the nakedeye any longer, even under the best
            > of skies.
            >
            > I'd certainly be interested in hearing how others are faring at this
            > point, especially without optical aid. 17P has certainly put on one
            > heck of a show...one of the most menorable in my 50+ years of comet
            > observing.
            >
            > JBortle
            >
            >
          • Brian Cudnik
            I saw the comet faintly by naked eye last Friday ( = 2:00UT 9 February) from our club s Dark Site (after the cirrus moved on...the site is located just west of
            Message 5 of 18 , Feb 11, 2008
              I saw the comet faintly by naked eye last Friday ( = 2:00UT 9 February) from our club's Dark Site (after the cirrus moved on...the site is located just west of Columbus, Texas), and also through binoculars. It appeared large and faint in both instances: through binoculars it appeared about 1.5 X 1.25 degrees in extent, with the central brightening still present.

              I seem to be having trouble finding the fainter ones lately. At the same Site, I used the 14-inch SC to look for C/2008 C1, 29P, and 93P and was not able to find any of them at 98X. The sky was clear with average transparency, but at least C1 and 29P should have been bright enough to pick up (I picked up Wirtenann no problem...). This also happend on December 30 under better sky conditions...I could not find these comets. Are they diffuse or am I losing my touch?

              Thanks and clear skies...Brian Cudnik




              [Non-text portions of this message have been removed]
            • Piotr Guzik
              John, I still could see 17P with naked eye last evening (Feb. 10.75), though the conditions were just pretty good (NELM~6.5 in zenith, M33 barely visible with
              Message 6 of 18 , Feb 11, 2008
                John,

                I still could see 17P with naked eye last evening (Feb. 10.75), though
                the conditions were just pretty good (NELM~6.5 in zenith, M33 barely
                visible with naked eye. Bortle class 4/5). The comet was only faintly
                visible with averted vision but it was still there.
                As it is now extremely huge, its surface magnitude is diminishing very
                slowly (>0.02 mag/day) and I think it will still be visible with naked
                eye under dark sky after full moon.

                Best Regards
                Piotr Guzik
              • Alan_Hale
                Dear John, and all, When I last observed 17P three nights ago (February 9 UT), it was still visible to the naked eye without too much difficulty -- very large
                Message 7 of 18 , Feb 11, 2008
                  Dear John, and all,

                  When I last observed 17P three nights ago (February 9 UT), it was still
                  visible to the naked eye without too much difficulty -- very large and
                  vague, certainly, and not the obvious thing it was back in November/December
                  -- but still definitely there, about overall m1 ~4. I'm observing from a
                  dark site, 2200 meters elevation, with no light pollution -- and that
                  obviously helps.

                  Don't know if it will still be naked-eye visible after the moon, but I think
                  there's a reasonable possibility that it will be. Weather permitting, I'll
                  probably be observing it during the lunar eclipse next week.


                  Sincerely,

                  Alan
                • Maik Meyer
                  Hi all, I have stopped trying to estimate 17P by naked eye since I simply do not know how to do it! When I was under very dark skies at the end of January the
                  Message 8 of 18 , Feb 12, 2008
                    Hi all,

                    I have stopped trying to estimate 17P by naked eye since I simply do not
                    know how to do it! When I was under very dark skies at the end of January
                    the comet was easy to spot by naked eye, but it was so large that I had no
                    idea how to defocus the stars without instrumental aid. My usual procedure
                    was to simply take off my glasses to have the stars out of focus and it
                    worked well as long as 17P's size was not too large. But now it is so large
                    that my wrong eyesight is not wrong enough to defocus the stars.

                    I guess the only way to obtain such a large defocusing is by using strong
                    spectacles... but then the star disks will overlap and are hard to separate
                    when near the edge of vision.

                    I would be interested to hear how you are doing the naked eye estimates.

                    Cheers, Maik
                    --
                    If they give you ruled paper, write the other way. * Juan Ramon Jimenez
                    ________________________________________________________________________
                    maik@... http://www.comethunter.de
                    German Comet Section http://www.fg-kometen.de
                    http://groups.yahoo.com/group/comets-ml
                  • Szabo Sandor
                    To Brian: all these comets you asked were very diffuse on 10.8 Feb. We saw 29P and C/2008 C1 without difficulty. 93 P (Lovas) was faint, 13.8 mag and 30 ,
                    Message 9 of 18 , Feb 12, 2008
                      To Brian: all these comets you asked were very diffuse on 10.8 Feb. We saw
                      29P and C/2008 C1 without difficulty. 93 P (Lovas) was faint, 13.8 mag and
                      30", DC:2. We observed with 50,8 cm Dobsonian.
                      17P was easy with naked eye and could be seen with direct vision also. But
                      we could not find the inside coma (even it was 12.4 mag on 26th January. Now
                      the limiting magnitude was around 15.5 and it was predicted to be 20" fom a
                      13 mag star).
                      Sandor Szabo


                      ----- Original Message -----
                      From: Brian Cudnik
                      To: comets-ml@yahoogroups.com
                      Sent: Monday, February 11, 2008 6:19 PM
                      Subject: Re: [comets-ml] Final Nakedeye Observation of 17P?


                      I saw the comet faintly by naked eye last Friday ( = 2:00UT 9 February) from
                      our club's Dark Site (after the cirrus moved on...the site is located just
                      west of Columbus, Texas), and also through binoculars. It appeared large and
                      faint in both instances: through binoculars it appeared about 1.5 X 1.25
                      degrees in extent, with the central brightening still present.

                      I seem to be having trouble finding the fainter ones lately. At the same
                      Site, I used the 14-inch SC to look for C/2008 C1, 29P, and 93P and was not
                      able to find any of them at 98X. The sky was clear with average
                      transparency, but at least C1 and 29P should have been bright enough to pick
                      up (I picked up Wirtenann no problem...). This also happend on December 30
                      under better sky conditions...I could not find these comets. Are they
                      diffuse or am I losing my touch?

                      Thanks and clear skies...Brian Cudnik

                      [Non-text portions of this message have been removed]
                    • cnj999
                      ... do not ... January ... had no ... procedure ... and it ... so large ... strong ... separate ... estimates. ... Indeed, determining this object s
                      Message 10 of 18 , Feb 12, 2008
                        --- In comets-ml@yahoogroups.com, "Maik Meyer" <maik@...> wrote:
                        >
                        > Hi all,
                        >
                        > I have stopped trying to estimate 17P by naked eye since I simply
                        do not
                        > know how to do it! When I was under very dark skies at the end of
                        January
                        > the comet was easy to spot by naked eye, but it was so large that I
                        had no
                        > idea how to defocus the stars without instrumental aid. My usual
                        procedure
                        > was to simply take off my glasses to have the stars out of focus
                        and it
                        > worked well as long as 17P's size was not too large. But now it is
                        so large
                        > that my wrong eyesight is not wrong enough to defocus the stars.
                        >
                        > I guess the only way to obtain such a large defocusing is by using
                        strong
                        > spectacles... but then the star disks will overlap and are hard to
                        separate
                        > when near the edge of vision.
                        >
                        > I would be interested to hear how you are doing the naked eye
                        estimates.
                        >
                        > Cheers, Maik

                        Indeed, determining this object's intergrated magnitude, once it
                        became very large, must be a considerable problem for most and I'm
                        equally curious to know how others have managed to handle it. I'm
                        rather concerned that many observers are using methods that really
                        don't operate well in this extreme case, perhaps leading to somewhat
                        questionable accuracy.

                        I would note that there is some problem with simply removing one's
                        eyeglasses (or, alternately, putting on stronger reading glasses) to
                        obtain defocused star images. Since the defocused star sizes will
                        closely match the coma diameter of the in-focus comet only for a
                        specific, limited interval, outside this time interval the brightness
                        estimates will be increasingly off the mark. When the star-disks
                        appear somewhat larger than the comet's actual size, the comet will
                        be estimated somewhat too bright, while just the opposite will be
                        true when the comet becomes significantly larger appearing than the
                        star disks.

                        Moving the eyeglasses further from the eyes does allow for some
                        additional latitude in creating extrafocal diameters but there does
                        appear to be shortcomings in this method, as well.

                        So, I would second Maik's request for observers to post just what
                        method(s) they have employed in determining 17P's brightness since
                        about the turn of the year. Such would, I think, provide an
                        interesting comparison, insight into what various observers believe
                        is the appropriate approach in this unusual situation and a lively
                        discussion of methodology.

                        I had to halt my m1 determination with the unaided eye back in mid
                        December, when 17P reached about 1 degree in size. However, I had
                        been making simultaneous observations, using 3x25 opera glasses,
                        since mid November. These have worked very well and for my most
                        recent determinations, I've removed the retaining screw that holds
                        the 3x25 opera glasses eyepiece frame to the body of the unit. Doing
                        so allows them travel far beyond their intended focal range and
                        provided me with a range to defocus the stars to match the coma's
                        size without regard to how large 17P was.

                        JBortle
                      • Piotr Guzik
                        Hi All, Last night (Feb. 24th) I still could see 17P with naked eye. At first I observed it from my backyard. Conditions were very good - I could see stars
                        Message 11 of 18 , Feb 25, 2008
                          Hi All,

                          Last night (Feb. 24th) I still could see 17P with naked eye. At first
                          I observed it from my backyard. Conditions were very good - I could
                          see stars down to about 6.8 mag, M33 and zodiacal light were clearly
                          visible with naked eyes. The comet was just visible to naked eye as
                          ~60' very diffuse round object ~5 mag.

                          Later (~19 UT) I drove 15 km from my backyard to definitely darker
                          place (I'd say Bortle Class 2/3). The Milky Way in Puppis was visible
                          to about 10 degrees above horizon. NELM was definitely better than
                          7.0 mag as I could see GSC 4384 1160 (7.1 mag) with averted vision.

                          There the comet looked much better. It was still noticeable without
                          much difficulty as ~4.5 mag round object approximately 100' in
                          diameter (though it was rough estimate).

                          Best Regards
                          Piotr Guzik
                        • martin mc kenna
                          Hi all Comet 17P/Holmes can still be seen fairly easy with the naked eye using direct vision when the sky conditions are good. Even last night at 00.30 UT when
                          Message 12 of 18 , Feb 27, 2008
                            Hi all

                            Comet 17P/Holmes can still be seen fairly easy with the naked eye using direct vision when the sky conditions are good. Even last night at 00.30 UT when Perseus was low in the sky 17P was still detectable. Easy in binos but more difficult in a telescope.

                            A few wide field images (scroll down) from myself and John McConnell...

                            http://www.nightskyhunter.com/Sky%20Events%20Now.html

                            Sketch of 46P/Wirtanen...

                            http://www.nightskyhunter.com/Comet-70-70.html

                            Mag: 9.0 Dia: 6' D.C: 3

                            Martin Mc Kenna
                            N. Ireland

                            Piotr Guzik <g22@...> wrote:
                            Hi All,

                            Last night (Feb. 24th) I still could see 17P with naked eye. At first
                            I observed it from my backyard. Conditions were very good - I could
                            see stars down to about 6.8 mag, M33 and zodiacal light were clearly
                            visible with naked eyes. The comet was just visible to naked eye as
                            ~60' very diffuse round object ~5 mag.

                            Later (~19 UT) I drove 15 km from my backyard to definitely darker
                            place (I'd say Bortle Class 2/3). The Milky Way in Puppis was visible
                            to about 10 degrees above horizon. NELM was definitely better than
                            7.0 mag as I could see GSC 4384 1160 (7.1 mag) with averted vision.

                            There the comet looked much better. It was still noticeable without
                            much difficulty as ~4.5 mag round object approximately 100' in
                            diameter (though it was rough estimate).

                            Best Regards
                            Piotr Guzik






                            http://www.nightskyhunter.com/


                            ---------------------------------
                            Never miss a thing. Make Yahoo your homepage.

                            [Non-text portions of this message have been removed]
                          • Kenneth Drake
                            I ve tried seeing Holmes naked eye a number of times since my last positive NE view on January 29th from dark Ft. Griffin. Until last night, all have been
                            Message 13 of 18 , Feb 29, 2008
                              I've tried seeing Holmes naked eye a number of times since my last
                              positive NE view on January 29th from dark Ft. Griffin. Until last
                              night, all have been negative. I got home from work near 8:00 last night
                              and astronomical twilight had been ended about 20 minutes. The sky
                              looked like it had evaporated the clouds that had washed in from the
                              south during the day so I thought I would give comet Holmes another
                              look. I was standing just outside my back door to the garage looking up
                              at the location of the comet. Holmes was up about 60 degrees up to the
                              west northwest and I was using my hands to block the extraneous light
                              leaking around trees from a neighbors "yard light" 200 meters away. Like
                              a dummy, I then realized that I could use the corner of the eave I was
                              under to block 3/4 of the sky and my arms and hands to block the
                              remaining 25%. What was left was a small hole (~10 degree) where only
                              the light from the area of sky Holmes occupied was visible. I was rather
                              shocked to see Holmes appear as a very soft, round, weak glow just
                              slightly over half a degree in diameter using averted vision. The comet
                              disappeared with direct vision. It formed a shallow triangle with the
                              bright stars Xi and Epsilon. The 5.5 magnitude stars SAO 56628 and 56675
                              were beacons with direst vision. I did not notice the 6.6 mag SAO 56730
                              embedded in the glow of the comet. I consider my skies good but not
                              great (Bortle Class 5) and it may have helped that Holmes was placed in
                              the best part of my sky - looking away from all light pollution. I hope
                              others can use this trick.

                              Kenneth (drako) Drake


                              cnj999 wrote:
                              >
                              > I think I can say with some confidence that the sighting I made of
                              > 17P/Holmes about half an hour ago (Feb. 11.01UT) will be my last,
                              > barring some new outburst. The comet was at the extreme limit of
                              > averted vision for me, in my typically less than perfectly dark skies.
                              > It seemd to subtend roughly 2 degrees and was essentially circular in
                              > outline. At the same time, 15x70 binoculars still rather easily showed
                              > the comet, although not to the full diameter evident with the unaided
                              > eye.
                              >
                              > >From here on, the waxing moon will likely hide the comet from the view
                              > of most, until at least Fenruary 22nd, by which time I would not expect
                              > it to be detectable with the nakedeye any longer, even under the best
                              > of skies.
                              >
                              > I'd certainly be interested in hearing how others are faring at this
                              > point, especially without optical aid. 17P has certainly put on one
                              > heck of a show...one of the most menorable in my 50+ years of comet
                              > observing.
                              >
                              > JBortle
                              >
                              >
                            • Gabor Santa
                              Hello, I have seen Comet Holmes to the naked eye at 2nd March next to Szeged, Hungary. Location was at about 5 km NW to the city. Clear sky after cold front.
                              Message 14 of 18 , Mar 3, 2008
                                Hello,

                                I have seen Comet Holmes to the naked eye at 2nd March next to Szeged,
                                Hungary. Location was at about 5 km NW to the city. Clear sky after cold
                                front. Light pollution was low, background 20,5 mag/sq" (SQM data).

                                March 2,75 UT:
                                m1=5.0:, D=1deg:, DC=0, naked eye

                                Clear skies,

                                Gábor
                                Szeged, Hungary
                              • Alfredo Pereira
                                ... Hello Gabor, For the benefit of all of us interested, could you (and all those currently publishing _naked eye_ estimates for this object) please be so
                                Message 15 of 18 , Mar 3, 2008
                                  >Gabor Santa wrote:
                                  > I have seen Comet Holmes to the naked eye at 2nd March next to Szeged,
                                  > Hungary. Location was at about 5 km NW to the city. Clear sky after cold
                                  > front. Light pollution was low, background 20,5 mag/sq" (SQM data).
                                  >
                                  > March 2,75 UT:
                                  > m1=5.0:, D=1deg:, DC=0, naked eye

                                  Hello Gabor,

                                  For the benefit of all of us interested, could you (and all those currently
                                  publishing _naked eye_ estimates for this object) please be so kind as to
                                  describe which method you used to get this m1=5.0: value ? Thanks much.

                                  Cheers,

                                  Alfredo
                                  --
                                • Gabor Santa
                                  ... Hi, The method was Sidgwick. Gabor
                                  Message 16 of 18 , Mar 4, 2008
                                    >>Gabor Santa wrote:
                                    >> I have seen Comet Holmes to the naked eye at 2nd March next to Szeged,
                                    >> Hungary. Location was at about 5 km NW to the city. Clear sky after cold
                                    >> front. Light pollution was low, background 20,5 mag/sq" (SQM data).
                                    >>
                                    >> March 2,75 UT:
                                    >> m1=5.0:, D=1deg:, DC=0, naked eye
                                    >
                                    > Hello Gabor,
                                    >
                                    > For the benefit of all of us interested, could you (and all those
                                    > currently
                                    > publishing _naked eye_ estimates for this object) please be so kind as to
                                    > describe which method you used to get this m1=5.0: value ? Thanks much.
                                    >
                                    > Cheers,
                                    >
                                    > Alfredo

                                    Hi,

                                    The method was Sidgwick.

                                    Gabor
                                  • Gabor Santa
                                    ... Hi, The method was Sidgwick. Gabor
                                    Message 17 of 18 , Mar 4, 2008
                                      >>Gabor Santa wrote:
                                      >> I have seen Comet Holmes to the naked eye at 2nd March next to Szeged,
                                      >> Hungary. Location was at about 5 km NW to the city. Clear sky after cold
                                      >> front. Light pollution was low, background 20,5 mag/sq" (SQM data).
                                      >>
                                      >> March 2,75 UT:
                                      >> m1=5.0:, D=1deg:, DC=0, naked eye
                                      >
                                      > Hello Gabor,
                                      >
                                      > For the benefit of all of us interested, could you (and all those
                                      > currently
                                      > publishing _naked eye_ estimates for this object) please be so kind as to
                                      > describe which method you used to get this m1=5.0: value ? Thanks much.
                                      >
                                      > Cheers,
                                      >
                                      > Alfredo

                                      Hi,

                                      The method was Sidgwick.

                                      Gabor
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