Documentation for Asterisms data, version 3.2

Dated  December 10, 2013

by Steve Coe

The Asterisms data that accompanies this document contain information on all the asterisms that are known. (to the group of people I observe with;-)

The data are arranged in the following order:

NAME, the name of the asterism.

CON, the constellation in the IAU format.

RA, the Right Ascension (2000) in hours, minutes and decimal minutes.

DEC, the Declination (2000) in degrees and minutes.

MAG, the magnitude of the asterism.

SIZE, the size in degrees (d) or in arc minutes (') of the asterism.

TIR, the chart number of the asterism on the Star Atlas 2000 by Tirion.

BSA, the chart number of the asterism on the Bright Star Atlas.

NOTES, other information about the asterism.

Tip:  the SIZE field is going to determine the instrument you will want to use for observing an asterism.  Very large asterisms, such as the "Big Dipper" or "Winter Triangle" are going to be best with the naked eye.  Medium size asterisms, such as "Orion’s Sword" or the "Swoosh" in Scutum, will be best with binoculars or a wide field telescope.  The smaller asterisms, such as "Little Queen" or "Backwards 5" will be best in a telescope.  Use the best instrument to get the best view. 

Asterisms are fun groupings of stars that do not constitute an entire constellation, as a matter of fact some of these objects are on the border between multiple constellations.  But, with a wide field instrument or some binoculars, there is a lot to see.  

Do not count on the data here being precise.  I measured the size and magnitude of many of these asterisms using my planetarium program, Sky Map Pro.  I do believe that most of the positions are good enough to get the asterism into a wide field eyepiece in most telescopes.  

I am often at the www.cloudynights.com web site.  Contact me there if you have another asterism to add or if you have found an error to report.

Clear Skies;
Steve Coe