The plan was to shoot 60” OSC subs, and 180” mono subs. I chose shorter OSC subs to try to control star size and not blow out their cores so I could maximize color in processing. The first night was a little slow getting everything set up (I’ve lost my touch at polar alignment adjustments!) but I eventually got everything working. I woke up around 1 am to watch the meridian flip on the new mount to make sure it all was going smoothly. When I got outside, it was rather windy (consistent 10mph winds and 20 mph gusts.) I decided to bring everything inside after about 4 hours of imaging, as I figured this would be too much wind to get useable data. Surprisingly, the wind had a somewhat marginal impact on the FWHM measurements for both scopes - probably due to the larger pixel scale and wide FOV. It was approximately a 10-20% increase in FWHM for the C6, and a 20-30% increase for the Redcat. It seems like a larger change, but again, the larger pixel scale hides it well. After that experience and measurement, I feel a bit more comfortable that I will still get usable data when it’s a little breezy (though I still don’t want to image in gusts greater than 20mph since my gear is exposed to the wind). That said, I still got rid of some of the outlier FWHM measurements, and I needed to toss a good amount due to the subs being a little washed out due to some new LED street lights that came into play toward the end of the session. Plus, I had more imaging time planned anyway, so I felt I could be selective. Another fun fact - I looked at my weather station data in the morning and saw that the wind became calm about 30 minutes after I packed everything up. Win some lose some I guess!

The second night went perfectly - same plan: 60” OSC subs and 180” mono subs. I gathered 7hrs of Ha, and 7hrs of OSC data and kept almost every sub. I still woke up to monitor the meridian flip since I didn’t get to the first night. Everything worked perfectly. The next morning, I decided to take some flat and bias frames and practice processing some of the data, but I wasn’t going to be ready for full processing until I had Oiii data, which I planned to capture on night 3.

The third night was hit and miss. It was a bit breezy again at the beginning of the night, and the forecast called for calming winds by midnight, so I decided to give it a go. This time, I wanted to capture some 180” OSC subs to compare/combine with the 60” OSC subs, alongside some 180” Oiii subs. The Oiii subs were a hit - the C6 and Eq6r-Pro performed well, and I only tossed some subs due to the new light pollution nearby. The Redcat on the DIY mount was a different story: at the beginning of the night, I noticed the declination axis of the mount just wasn’t tracking. I sent it back to its home position and re-tried the imaging plan and it worked great. I decided to just sleep since I was comfortable with the meridian flip. I came down that morning and saw the Redcat was not parked in it's home position like usual, and instead was tilted on the declination axis. Based on its position, I concluded that it happened after the meridian flip at some point. I was not able to return the mount to its home position, even after restarting the mount, so I’m going to open the mount up tonight and see if I can figure out what happened. I only got about 90 180” minute OSC subframes out of the night, however, I had plenty of OSC data, so I decided to process it all.

Processing was a bit of re-learning, especially since I hadn’t done much continuum subtraction before (I did on my M33), and there’s been lots of new techniques and tools that have come out this year. However, my general process was the same: Blink and Subframe Selector in Pixinsight to remove any outlier frames. Stacking in Siril. Back to Pixinsight for Spectrophotometric Flux Calibration > Multiscale Gradient Correction > Background Neutralization > Spectrophotometric Color Calibration (at this stage, I found SPCC gave the OSC images a magenta cast for some reason. I ran Background Neutralization again, which helped, but it require lots of manual curves adjustments later.) Next was BlurX and Starnet to produce star masks and starless images for the 60” and 180” OSC stacks, and starless Oiii and Ha images. I then ran Photometric Continuum Subtraction for the Ha and Oiii images against the Red and Blue channels respectively, of the 180” RGB image. I then ran Statistical stretch and NoiseX on the OSC images and blended them. I also ran Statistical Stretch on the Continuum Subtracted Ha and Oiii images, and then ran NoiseX on those as well. I made some curves adjustments to the Ha and Oiii data to zero out the background and increase the highlights. I then spent ages working on the OSC data, trying to remove the magenta cast. Lots of masking, and little saturation, hue, chrominance, and RGB/k curves adjustments until I felt like it was in a better spot. I ran a masked HDR Multiscale Transform to recover some of the galaxy’s core. I ran an Unsharp Mask to recover a little more detail on the RGB image. I then used the CombineRGBandNarrowband script to combine the images. Finally, I ran the Star Stretch script and compared the 180” and 60” star masks. The 60” star mask did not produce as many faint stars as the 180” star mask, and the cores of the brighter stars all looked similar to me, so I opted to use the 180” star mask for the image. Before combining them, I ran Convolution to soften some of the smaller, blocky stars a little bit. I combined the star mask and the RGB/Narrowband image and this is the result! Enjoy!