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Re: (IAAC) LM Star Count vs Milky Way Perception
Folks use a variety of methods for determining sky darkness, Scott...
(Many of them are listed as options on the IAAC Web form for entering
logs:
http://www.tiac.net/users/lewkaren/netastrocatalog/enter-log.html )
I use the simple International Meteor Organization "star-count" method
myself. This involves counting the stars I can see averted vision,
inside of one of 30 different well-defined triangles and squares
around the sky.
I use this method for several reasons:
1) I'm already very familiar with it from meteor watching
2) It IS a standard, quantitative method - at least among meteorists
3) I can always find areas near the zenith or the object I'm after
4) I can do counts and NOT prejudice my results with expectations
Number (4) is very important - the problem with the "Ursa Minor" (or
Orion or Hercules or Great Square or...) methods is that I've noticed
it's very easy to "see" a star, once you already know it's there. :)
Those interested can see Bill Arnett's great Web site on how to do it:
http://www.seds.org/billa/lm/rjm.html
Or at the official IMO Web site at:
http://www.imo.net/visual/major01.html#table2
Of course as this thread demonstrates, the drawback is that measuring
stellar LMs (however accurately) may NOT be a good measure of how your
sky is for seeing a particular extended object! However it is the only
consistent, quantifiable, non-instrumented method I'm aware of.
Clear skies all!
Lew
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