Re: [APML] The faintest object

[Wei-Hao Wang <whwang@gmail.com>]

Hi Renzo,

You may want to take a look at "A Manual of Advanced Celestial Photography"
by Wallis and Provin.  There is a formula for photographic limiting magnitude.

The basic idea of the formula is, as Carlos pointed out, you cannot identify an 
object that is fainter than the sky.  More precisely speaking, this has to take 
into account the size of stars on the film and the S/N of the film.  The stellar
sizes are determined by seeing, optical system, and film grains.  The S/N of
the film can be calculated from its RMS grainularity.  Knowing these and the
sky brightness, one can fully reproduce the formula given by Wallis & Provin.

Cheers,

Wei-Hao 
-- 
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Wei-Hao Wang  :)

Institute for Astronomy at University of Hawaii

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