Caldwell 4 - The Iris Nebula

I revisited the Iris with a new setup! If you’ve been following along recently, I have been struggling to shield my C9.25 from wind. I decided a good interim solution would be to use a scope with a smaller form factor, such as a mid-length refractor. I finally found an Astro-Tech AT115EDT on Astromart that seemed to fit what I needed. I must say, I had forgotten how simple things can be! I just take it outside, let it come to temperature for about 30 minutes, and I’m ready to go! There’s not much else to do than PA, focus, pick a target, and get the plan running. I’ve been getting stellar guiding numbers using my OAG (usually about .3”-.4” total RMS), even in the typical gentle breeze up to about 5-7mph. FWHM is generally between 2-3, and even below 2 on some subs. I did toss out a few because I’m still tweaking the EAF settings… I think the Coarse and Fine adjustments still need some tweaks. Overall, I’m pleased - I can finally get back to imaging and not waste a clear night, rather than waiting for it to be absolutely perfect. This also gives me more time and less pressure to think of a windbreak solution for the C9.25 as well.

For this result, I ended up with 190 frames, and had to toss about 50 of 240 frames due to some thin clouds overnight. Processing on this was tough as well. Dark nebula are always a challenge, and this one is out over Denver’s light dome, which makes it more challenging. I made use of masks pretty extensively, and did my best to manage the LP gradient since I was just using a UV/IR filter. I could probably stand to add more data, and cull more frames to bring it out more, but I’m ready to try another target, now that I’m more familiar with the new scope.