02/18/2023 – EAA – A Different Look…

First bit of clear night sky in nearly a week. The forecast was calling for clouds around 9 PM but I set up to have a quick look. I did not do a polar alignment or shoot any calibration frames, I knew time was going to be short so I just wanted have a quick look at a couple of objects.

One thing different about this session was that I was observing at the full focal length of the scope. I removed the focal reducer to get an idea of what kind of EAA results I could achieve with out it. With out the focal reducer the SV503 102ED has an advertised focal length of 702 mm, plate solving calculated the actual at 713mm. Since I removed the focal reducer I did have to refocus and after a couple of Ekos Auto Focus routine runs the focus ended up at 16970 steps.

The EAA images in this post were capture with my ZWO ASI294MC Pro cooled to -10 C through my SVBONY SV503 102ED Scope and a SVBONY IR/UV Cut filter. The SV503 is focused using a ZWO EAF and the Ekos Focus Module. All gear is mounted on a Sky Watcher EQ6-R Pro. The mount and cameras are remotely controlled with KStars/Ekos with INDI Server running on a Raspberry Pi. The images were live stacked using SharpCap Pro. Images have been resized (80% of original) and/or cropped for file size but otherwise appear just as I observed them.

M81, Bode’s Galaxy, and M82, the Cigar Galaxy, in the constellation Ursa Major. This is a live stack of 60 x 10 second and 76 x 15 second of exposures (29 minutes total) at 121 gain, 30 offset, and bin 2×2. Why only 29 minutes? I had set it up for 30 minutes but Ekos crashed when I tried to search for an object while the capture sequence was running.
M81 and M82 EAA Capture 02/18/2023
Not bad with out the focal reducer. There is a little elongation of the stars in the corners. The extra ~140mm of focal length did bring M81 in a bit closer. For the short subs there is some good detail. Some good detail in M82 as well. New calibration frames, especially flats, probably would have helped a fair bit but ain’t nobody got time for that 🙂

M1, the Crab Nebula, a supernova remnant in the constellation of Taurus. This is a live stack of 60 x 15 second exposures (15 minutes total) at 121 gain, 30 offset, and bin 2×2.
M1, The Crab Nebula, EAA Capture 02/18/2023
Again the extra bit of focal length brought the Crab Nebula a bit closer in. I can just see some of the filaments of the nebula, and this is probably the best color I have captured of M1. Norvin, my buddy down the street, was also capturing M1 through his SV503 80ED, so I grab these captures for us to compare.

Enjoyed the little extra focal length which came with removing the focal reducer. There is a little bit of distortion in the corners without it, but that was kind of expected. For EAA this is not really an issue since the focus is usually what is in the center of the FOV.

I went out to cover the scope around 8:45 PM. Clouds were starting to move in from the North. For a short night it was a good night. It was also a cold night, temperature was around 34 F when I went out to cover the scope, some frost had started to form on my table.

Hopefully there will be more clear skies soon.

Leave a Reply

Your email address will not be published. Required fields are marked *

4 − 3 =