M51 - Whirlpool Galaxy
March 18, 2026
Whirlpool Galaxy from my backyard using a $229 color camera. I captured 133 120-second subs of M51 last night with the ZWO ASI715MC camera and the Apertura CarbonStar 150 (600mm focal length). I stacked 115 good subs, no calibration frames, and the result is pretty good.
Trouble I ran into with this combination--ASI715 + 600mm OTA:
- I had serious trouble plate solving with a resolution: 0.5"x0.5" per pixel and a Field of View of 0.54° x 0.3°. It may have worked once and I found my FL set to 505mm on the 600mm scope, but I couldn't get any plate solving to work for polar alignment or after a meridian flip. The ASIAir minimum FoV is 0.4° for solving (possibly 0.2°), and I don't see a way to help that out. I will try blind solving next time I'm out, setting the focal length for plate solving calculation to 0, which lets the ASIAir run through a series of FLs to solve.
- Focusing worked as well as can be expected with the 0.5 arcseconds per pixel resolution, but stars are bloated and very soft, oversampled.
