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Re: [comets-ml] Comet Visual Limiting Magnitudes

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  • David Seargent
    ... From: Greg Crinklaw To: Sent: Wednesday, October 30, 2002 8:42 AM Subject: [comets-ml] Comet Visual
    Message 1 of 10 , Oct 31, 2002
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      ----- Original Message -----
      From: Greg Crinklaw <crinklaws@...>
      To: <comets-ml@yahoogroups.com>
      Sent: Wednesday, October 30, 2002 8:42 AM
      Subject: [comets-ml] Comet Visual Limiting Magnitudes


      > Hi,
      >
      > I'm writing an article about comet observing and would like to include a
      > very general idea of the faintest comet "generally visible" in
      > instruments of various apertures.
      >
      > By generally visible I mean a faint comet of typical size with a typical
      > degree of concentration as seen from a dark site without great difficulty.
      >
      > I am aware that there are many variables here; I'm merely looking for a
      > general idea of the faint limit.
      >
      > In my own experience I use a cutoff of 13.5 to 14th magnitude with my
      > 18-inch Dob, and something around 12.5 magnitude for my 6-inch. I would
      > very much appreciate knowing what others consider to be the general
      > limit of their telescope.
      >
      > Thanks!
      > Greg
      >
      > --
      Greg,

      I have managed to see two comets with my 10" F/4.5 that I estimated at 13.7
      and 13.8. The first was SW1 and the second P/Mrkos. In each case, they were
      almost asteroidal. A "normal" comet of 13.4 is probably the best that I can
      do under very dark skies. Interestingly, I once saw a comet of 11.1 with
      15x80 binoculars after first locating it in a 6" reflector, but that one was
      also very small and condensed. About 10.5 is more normal for these
      binoculars.

      Regards,

      David Seargent
    • Stéphane GARRO
      Hello Greg, ... Under a dark mountain sky (with a nake-eye limit magnitude of 7,0 to 7,5) I was able to easily see comets up to m1=13,2. Could see fainter ones
      Message 2 of 10 , Nov 7, 2002
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        Hello Greg,

        le 29/10/2002 22:42, Greg Crinklaw à crinklaws@... a écrit :

        > I'm writing an article about comet observing and would like to include a
        > very general idea of the faintest comet "generally visible" in
        > instruments of various apertures.

        Under a dark mountain sky (with a nake-eye limit magnitude of 7,0 to 7,5) I
        was able to easily see comets up to m1=13,2.
        Could see fainter ones but as a challenge, and difficult to confirm the
        detection. The faintest comet I ever saw was P/SL9 at m1=13,7 (detection
        confirmed after by taking a photograph).

        Wishing good sky to all. Stephane



        [Non-text portions of this message have been removed]
      • john_drummond@xtra.co.nz
        Hello Greg, I find that with my 16 f4.5 Meade Starfinder Newt I can see down to a stellar LM of 15.6 and a diffuse LM of 14.4 on most moonless nights - thus
        Message 3 of 10 , Nov 7, 2002
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          Hello Greg,

          I find that with my 16" f4.5 Meade Starfinder Newt I can see down to a stellar LM of 15.6 and a diffuse LM of 14.4 on most moonless nights - thus the fainter comets I observe are about 14 - 14.5. This is from the edge of a 30,000 pop city - naked eye LM about 6 most nights...

          John Drummond
          NZ

          > I'm writing an article about comet observing and would like to include a
          > very general idea of the faintest comet "generally visible" in
          > instruments of various apertures.



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