Aquarius and M2 rise late-evening

Event Date: July 28th
Time: 11:00 PM

Brief

During late evening hours, a cluster that receives little attention by most beginning astronomers, rises in the east-southeast: a globular cluster labeled M2.  If you remember earlier this month when I talked about the Crab Nebula, the comet-lookalike that inspired Charles (M)essier to create his deep-sky catalog, I mentioned this one labeled as M1.  M3, I talked about earlier in the year as a fine globular cluster which gets high in the sky. 
   Let us look to see where M2 is in relation to a +2.9 magnitude star in Aquarius-- its parent constellation. 4.8º away from the cluster, is the star Sadal Suud.  At almost the same magnitude, Sadal Melik, another star not from M2, is extremely close to the celestial equator (1/4º away).  M2 itself, is only 3/4º away from the equator, which is about the same separation of Polaris from the north axis.

Detailed

M2 is slightly dimmer than 3, yet looks about the same.  One reason for this perhaps, is that 2 and 3 are estimated to be almost the same distance away, at 37,000 and 35,000 light years respectively. 
As for what else is worth knowing about M2, it is magnitude 7.5, 23 arc-minutes in in size (about 3/4 that of a full Moon at perigee), 100,000 stars and possibly visible to the unaided eye with a dark enough sky.  This last part is worth remembering, because--like Aquarius itself--M2 is far from the galactic plane, and there is no interference of a Milky Way band behind it.  If you remember my showings of constellations of Gemini and Sagittarius, they are backed by the billions of stars that make up our Milky Way.  These stars can easily distract the eye from deep sky objects visible to the eye alone.
   Compare the two with their images following the detailed section, for a close up of both M2 and M3 in 1º fields.  M3 is low in the west-northwest during this hour in July, and we will slowly lose it to the horizon as the months get us into the fall. 
   Which cluster of the two do you like better...one over the other?  When viewing, remember to use an eyepiece that magnifies it enough, yet not small enough in focal length that contrast degrades; one leading to the cluster losing its brightness against the background sky.  M3 is larger in angular size, at 48 arc-minutes, although it takes a dark sky to see lots of the stars far from the core.

click on images to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.