Mars and M22

Mars shines near the globular star cluster Messier 22 in Sagittarius.

This week Mars has been passing near one of the brightest globular star clusters, M22. I caught the pair tonight, November 8, as they sank into the southwestern sky.

The two form a contrasting pair, with red Mars now 260 million kilometres away, far enough that its light takes 13 minutes to reach Earth. However, blue M22 lies so far away, toward the galactic core, that its light take 10,000 years to reach Earth.

Mars appeared closer to M22 earlier this week but tonight was the first night with a narrow window of dark sky between twilight and moonrise, allowing me to shoot the pair.

I shot the image through a telescope with a short focal length of 400mm, taking in a field of about 5 by 3 degrees, the field of high-power binoculars. The image is a stack of eight 2-minute exposures at f/4.5 with the TMB 92mm refractor and Canon 6D at ISO 800.

3 Replies to “Mars and M22”

Thank you, Alan, for an unusual image: a field of a few degrees, and a doubly-limited time interval, between twilight and moonrise (on November 8), and with Mars near that magnificent globular cluster (for a few days). With M22 low in the SW, obviously you had a good sky.