Goodness Gracious! A Great Ball of Stars!


This is what half a million stars look like when packed into one big ball. 

This is the globular star cluster called Messier 22, in Sagittarius. It’s the biggest and best such object visible from Canadian latitudes, though it always sits low in our summer sky. M22 is one of 150 or so such spherical clusters of stars that orbit our Milky Way. This one sits 10,000 light years away from us, toward the centre of the Galaxy. Those half million stars are packed into a sphere 100 light years across. In our sky it appears as big as the Full Moon, though not as bright of course. But just imagine the sky if you can view it from the centre of M22. The heavens would be ablaze with stars. 

I shot this with the 130mm refractor at f/6. It’s a stack of just three 4-minute exposures with the Canon 7D. Though M22 was low above the southern horizon from the Cypress Hills where I shot this, the final image turned out pretty well. 

– Alan, August 30, 2012 / © 2012 Alan Dyer

 

The Comet and the Cluster


This was the scene Monday night and into Tuesday morning, August 1/2, as a relatively new comet to our skies passed a bright globular cluster known as M15 in Pegasus. The comet is Comet Garradd, or more formally C/2009 P1. Here it glows with the characteristic cyan tint of many comets and sports a stubby fan-shaped tail.

As comets move across the sky they often appear near prominent deep-sky objects for a night or two before moving on. Comet Garradd has a number of such encounters coming up: with the globular cluster M71 on August 26, and then near the neat Coathanger cluster September 1 through 3.

Comet Garradd can be spotted now from a dark site in big astronomy binoculars and is a fine sight in a telescope. However, it is well below the threshold of naked-eye brightness and is expected to remain so as it moves high across the summer sky from east to west and then into the western evening sky in late autumn. It is certainly well-placed for viewing, but only comet aficionados are likely to pay much attention to it. Plus astrophotographers taking advantage of photo ops like this one.

— Alan, August 2, 2011 / Image © 2011 Alan Dyer