Cassiopeia Observatory logo

An Oops, Omega Centauri Globular Cluster

Posted: 26 May 2022

Open: Wednesday, 25 May 2022, 1847 MST
Temperature: 85°F
Session: 1771
Conditions: Clear, breezy

12" f/8 LX600 w/StarLock
2" 24mm UWA eyepiece
2" UHC filter


1855-2000 MST: Relaxed on the observatory patio bench.

1924 MST: Sunset. Calm now.

Prepared the D850 DSLR for imaging.

2002 MST: LX600 ON, StarLock OFF, High Precision OFF.

Slewed to M104 (Sombrero Galaxy). It was not yet visible in the twilight sky.

2007 MST: Dome OFF.

2008-2045 MST: Relaxed on the bench again to watch the stars come out.

Viewed M104 (Sombrero Galaxy), 102X.

Mounted the D850 DSLR at prime focus + UHC filter, focused on the star Spica using a Bahtinov Mask, and locked the 12" telescope primary mirror. Then slewed to M104.

2051 MST: StarLock ON.

I took several images of M104 (Sombrero Galaxy) and then Omega Centauri (globular cluster) over a nearly one hour period. I then discovered that I had left the Bahtinov Mask on the telescope! STUPID! I had wondered why the images on the camera screen preview looked so faint.

I removed the mask and took this StarLock autoguided image of Omega Centauri (globular cluster), 1 minute, ISO 800, White Balance 4550K.


As the next day would be a busy one, I had to end my imaging session.

Viewed Omega Centauri (globular cluster), 102X.

2157 MST: LX600 OFF.

2200 MST: Dome ON.

2204 MST: Took a Sky Quality reading and reported the result to Globe at Night.

Close: Wednesday, 25 May 2022, 2209 MST
Temperature: 72°F
Session Length: 3h 22m
Conditions: Clear, SQM 21.12

I have received this International Dark-Sky Association cap and T-shirt.


I also received this Cassiopeia Observatory keychain.


Comments are welcome using Email. Twitter users can use the button below to tweet this report to their followers. Thanks.

Previous report

Cassiopeia Observatory Home Page

Back to Top

Copyright ©2022 Michael L. Weasner /