Deep Sky

Globular Cluster
In the constellation Ophiuchus, this cluster is 16,000 light-years from earth.  The central region is about 70 light-years across.  A nice 6.6 magnitude good for both small telescopes and binoculars.  This cluster kind of sums up a lot, the yellow stars are like our sun, burning hydrogen into helium at the core.  Once that  phase is over, hydrogen burns in a shell surrounding the stellar core resulting in the star expanding into a red giant.  (Red giants are in this image, just hard to see.)  The bright blue stars, again hard to see, having passed the stage have become 'horizontal branch' giants.  They at the core they are burning helium into carbon. Lastly, the gray stars probably are still burning hydrogen at t.heir cores