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Re: (meteorobs) Visual magnitude
Thanks for the reply, Rainer! The first part of my answer is a little off-topic
for meteorobs, but there's also a question for y'all at the end...
There's a variety of formulae which deep-sky nuts (like Brian Skiff, Steve
Waldee, Mel Bartells) have developed for describing how easily a particular deep
sky object can be spotted against the sky background, under certain conditions.
One of the most interesting of these are the algorithms for figuring out the
"optimal detection magnification" for an object - the power to use on a given
telescope, under sky with a given brightness, to MAXIMIZE the likelihood of
spotting that object in the eyepiece. The more sophisticated of these formulae
actually take into account the spectral characteristics of the objects involved,
and the effects of using various filters too.
I'm not that familiar with the details of these algorithms, but they seem to
revolve around the log-relative contrasts between the object and the sky.
You also wrote:
>If the sky is lit up lm for stars and meteors may separate significantly.
This is referring to the provision that meteor data collected under skies with
LMs below 5.0 (or so) are not useful for rate analysis, because of the large
correction factors involved? But I had always assumed that this 5.0 limit had
more to do with small sample size (you just don't see too many meteors from a
parking lot), and maybe with the use of LM=6.5 as the "standard sky" centerline,
than with any inherent divergence between stellar and meteor detectability!
What are the factors that contribute to this divergence? Is it because meteors
are actually slightly extended objects, or because of some property inherent in
their light emission which makes them on average less detectable than a sampling
of stars with many spectral types? This one made me really curious!
Thanks, and clear skies y'all!
Lew
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