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Re: (IAAC) limiting magnitude



Hi -
Get a copy of Roger Clark's "Visual Astronomy of the Deep Sky" (Cambridge)
which is out of print, but copies are still on the shelves of bookstores
and can be readily purchased at swap meets and borrowed from Astro Club
libraries.  Also, Mel Bartles Web page has an article on limiting
magnitude.
Clear skies,
Randy J. Rogers
<stardot@mcione.com>
----------
> From: celsom-w <celsom-w@amauta.rcp.net.pe>
> To: netastrocatalog-announce@latrade.com
> Subject: Re: (IAAC) limiting magnitude
> Date: Monday, March 02, 1998 6:21 AM
> 
> Hola Clouseau (The Pink Panther?):
> 
> Clouseau@webtv.net wrote:
> > 
> > Hello everyone,
> > 
> > I am trying to find some informtion that may not exist. Is there a
> > publication that with a known limiting magnitude will tell you if an
> > object you are trying to observe will be bright enough to see? For
> > example, if you have a limiting magnitude of 6, is there a way to
> > determine if you can see a magnitude 12 object? I think someone once
> > told me of a book that had information in it that would let you
> > determine that. Or, is there some type of formula you can work with
that
> > will let you know?
> > 
> > I know experience is the best teacher. But, right now, I feel like I'm
> > wasting a lot of time looking for things that are just too dim for my
> > sky conditions. The problem is that I don't know if the objects are too
> > dim or if I'm just not pointing the telescope at the exact right spot.
> > 
> > Can anyone help me on this one?
> > 
> 
> I think this is a personal experience. With my 60 mm refractor, I can
> reach mag 8-9 when in Lima, with limiting magnitude (LM) of 3-4. When LM
> is 5-6, I can see 9.5 stars easily and 10-10.5 hardly. At LM 6-7 I can
> more easily see 10.5 stars, depending on the state of the atmosphere. Of
> course, you can see nebulas or objects of mag. 11 only with averted
> vision and after a long time at the eyepiece. But the same night, at the
> same time, I can see better than my friends when the eyepiece field is
> empty of bright objects, but is difficult for me if any brighter star is
> on the area. This is why I try to see the objects moving the field so
> the brighter objects are outside the area. Even in the clearest skies,
> it is difficult for me to see objects in the 11-12 mag. range, using
> this refractor. I am sure that this is very easy in a 6 or 8".
> -- 
> Celso Montalvo
> ELECONT INGENIERIA S. A.
> Lima-PERU
> 12o S; 77o W.
>