The Triangulum Galaxy ... Messier 33
The Triangulum Galaxy
This is a 3 hour 8 min exposure ...
Messier 33, is a spiral galaxy in the constellation Triangulum, that's located at a distance of approximately 2.81 million light-years. It's the third largest member of the Local Group, which also includes our Milky Way galaxy, and the Andromeda Galaxy (M31). It contains about 40 billion stars as compared to the Andromeda galaxy with a trillion stars and our own Milky Way's 250 billion. The galaxy is high overhead in early October at 1am.
This was the first 'good seeing' night that I had in about 6 months so I set my goal in capturing a 3 hour exposure.
After setting up and taking several test shots, I decided to go with 4 minutes sub-frames at an ISO setting of 1600 and a Skyglow City Light-Pollution Suppression filter.
When you look at the images coming in, you really need to use your imagination to envision the final product. As you can see in this picture, there certainly was a lot of imagination needed. I started recording the sub-frames at 10 pm when the target was about 45 degrees above the ENE horizon with the last frame at 1 am when the target was high overhead. (Any additional sub-frames would had been after a meridian 'flip' of the telescope mount as the target would have crossed over into the western portion of the sky-dome).
The Techy Stuff:
Telescope: 11" Celestron 11" Edge HD (f/10)
Adaptor: 0.7 Reducer resulting in a focal ratio of f/7
Telescope Mount: CGEM ii
Camera: Canon T7i (modified)
Filter: SkyGlow City Light-Suppression
Settings: ISO 1600, 240-second exposure
Total sub-frames: 47
15 Dark frames
12 Bias frames
Capture Software: Backyard EOS 3.1.16 Premium Edition
Stacked in PixInsight & cropped
Post processing in PixInsight & Photoshop CC
Guiding: Orion 50mm guide scope with StarShoot AutoGuider
Guiding Software: PHD 2
Guiding error: 1.21 seconds of arc
Outside temperature 72°, Dewpoint 68° at 11 pm
Bortle Light Pollution zone: 4.5 (Barely can see the Milky Way)
Sky Condition: 8.5 [scale of 0 (cloudy) to 10 (clear)]
Location: My Backyard, Savannah, GA
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