Globular Clusters

This is the time of the year to image globular clusters, some of my favorite targets. The bulk of them tend to be low in the southern sky which is a challenge considering seeing and refraction. M13 was included in the previous post. Several others acquired on the same night appear below. M55 was acquired on a later night. Images were averaged from 30x30s subframes acquired at 120 unity gain. Configuration was Celestron 8 , Starizona NightOwl 0.4x focal reducer, ZWO ASI294MC Pro CMOS camera. Update: Images reprocessed with GraXpert stretching and residual gradient removal.

Messier 3

Messier 4

Messier 5

Messier 10

Messier 12

Messier 13

Messier 55

So Begins Globular Cluster Season.

Globular clusters (GC) are some of my favorite targets for this time of the year with short spring and summer nights and the annoyance of daylight saving time. With sunsets around 2030 and astronomical twilight's around 2240 globulars can usually be acquired in less than 15 minutes making for productive nights of imaging. 

Why do I keep coming back to these low hanging fruits? I like to think I can improve on my past performance and take advantage very rare good seeing Northeast nights. Most of these targets are low in the southern sky making it challenging to image them with the denser more turbulent air and refraction.

A few recent examples appear below. All of these globulars were acquired from a favorite Harvard, MA darkish site with 15 x 30s subframes with a ASI294MC-Pro, Starizona Night Owl 0.4x focal reducer and Celestron 8 on an Advanced VX mount. 

While I call this Globular Cluster Season there are many more  open clusters favorably placed this time of the year. Look for images of those in up coming posts. 

Messier 3

Messier 5

Messier 53

Messier 13

Messier 92

NGC5897

Messier 4

Messier 10

Messier 12

Messier 14