(SNES) Stellar and Cluster Brightness Tool

["Les Coleman" <les11@cox.net>]

Hi Ernie et al

There has been a lot of discussion (hooray) on Ernie's brightness question.
I would like to point out a useful gadget (tool?) in the FDO Astronomy
Utility Tools kit. It allows you to estimate (quite accurately) the combined
brightness of  binary stars, open clusters, and even globular clusters. It
really isn't well suited to working on nebulae and galaxies but you can
horse around and get approximations. All you have to do is input something
like the following:

                             40*11 800*12 2000*13 5000*14 10000*15 50000*16

and press COMBINE. It will tell you this cluster would have a combined
magnitude of 2.9. It means of couse 40 11th magnitude stars plus 800 twelth
magnitude stars and so on. I'll leave you to estimate the number of visible
stars at each magnitude. Fractions magnitudes work fine. For example 61
Cygni (5.22) and (6.03) combine to give a magnitude of 4.8.

Kinda nifty, and a real drag to calculate by hand.

Ther are a host of other improvements. For example the wide range of ways
you can specify dates, times, angle and even decimal numbers is so wide open
that it requires to explanatory  notes to make things clear.  For example
you could specify a
date as "Next Friday at 9 PM" or "Tonight at 8:30" or "September 22, 2002
20:31:49" . Angles like 0.68774R , or
39^24'17"  or  39.404722^ or 10.94576% and other can be entered. By the way,
these are all the same angle in
RADIANS, Sexagesimal degrees, decimal degrees and percentage of a complete
circle! Why so many ways? Because ALL of these appear in astronomy books and
drive you crazy converting. You can choose any or all of the formats as
ouput as well.

There are tools to do all sorts of things with dates and times, convert
between your local horizon to Equatorial to Ecliptic coordinates (and vice
versa). There is a tool to calculate the air's index of refraction at
various angles (horizon to zenith).
There is a tool to calculate the angular distance between stars, and another
tool to calculate great circle distances on planets.
You can happily convert between spherical and cartesian coordinates. You can
see stars maps for various dates and Moon phases for various dates. IF IT
WASN'T FOR THE FACT THAT IT IS CLOGGED UP, I'D HAVE PUT IN THE KITCHEN SINK.

Les Coleman
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