M56: Globular Cluster in Lyra
September 2011 :
In July, we looked at M92, a fine globular cluster in Hercules that’s overlooked in favor of the easier-to-find M13. The same misfortune has befallen another globular cluster - M56 in Lyra. M56 is often bypassed by backyard astronomers who favor the planetary nebula M57, conveniently positioned midway between the stars beta (?) and gamma (?) Lyrae.
Locating M56 isn’t as difficult as you might think. Aim your telescope towards a point roughly midway between gamma Lyrae and Albireo (somewhat closer to Albireo) and begin a low-power search. You should come across a small roundish puffball quite similar in appearance to a tail-less comet.
Admittedly, M56 doesn’t rank among the finest deep-sky objects in the Messier Catalog. At a magnitude of 8.3 and angular size of 7’, it pales in comparison with M13 and M92. Recently, I viewed M56 with a variety of instruments. Through 10X50 binoculars, it resembled an out-of-focus star. A 4.5-inch f/8 reflector at 150X showed the barest hint of resolution. 200X with a 10-inch Dob resolved much of the cluster, although the center still appeared hazy.
M56 was discovered on the evening of January 19, 1779, by Charles Messier - the same night he independently discovered the Comet of 1779. Recent distance studies put this globular cluster at about 30,000 light-years from Earth, corresponding to an actual diameter of some 60 light-years.
Your comments on this column are welcome. E-mail me at gchaple@hotmail.com.
