Photo of the Week for August 11, 2017
When most stargazers hear the words “Hercules” and “globular cluster” together, M13 springs immediately to mind. And little wonder—after all, it is known as the Great Cluster in Hercules. But the constellation is home to a second, wonderful globular: M92. At magnitude 6.4 and spanning 14 arc minutes, it’s only a little fainter and smaller than its iconic neighbour. Perhaps it should be renamed the Almost Famous Cluster in Hercules.
This nicely detailed M92 portrait was captured by Doris Thibeault from her observatory southeast of Rimouski, Quebec. She used a 12.5-inch, f/8 PlaneWave Instruments corrected Dall-Kirkham astrographic telescope fitted with a SBIG STL11000CM monochromatic CCD camera to record sets of 10, 200-second exposures, each through red, green and blue filters.