Last October, I tried to make a widefield image of Comet C2025 R2 SWAN from my light polluted driveway in Friendswood, Texas.  The comet was crossing a bright section of the Milky Way filled with Messier objects, and I thought it would show a nice comparison of some objects on comet hunter Charles Messier’s famous list of “not-comets” and an actual small comet.  (With the long integrations of data possible now, the comet stands out for being obviously green, but the color would not be visible in visual observing.). I’d made one image from the darker skies in Sargent, Texas, but that image only used 7 minutes of data with the camera on a tripod. For this image, I put the camera on my tracking mount and collected 15 minutes of data.

Unfortunately, the light pollution from my driveway and the gradients it created were beyond my processing capability last October.  

Since then, I have learned some new PixInsight tools that allowed me to produce this image.  Two passes of MultiscaleGradientCorrection using two different scales cleaned up the gradient nicely.  And the Canon Banding Reduction script reduced the banding pattern in the image.  Yea for new tools!

Now I want to apply that knowledge to some other images …

Camera geek info:

• Canon EOS 60D in manual mode, 2 second exposure, ISO 800
• Canon EF 85 mm f/1.8 lens at f/2.0 manual focus at infinity
• Intervalometer 
• iOptron CEM40
• Friendswood, Texas Bortle 7-8 suburban skies

Frames:

• October 18, 2025
  • 451 2 second lights
  • 27 2 second darks
  • 32 1/2500 second flat darks
  • 33 1/2500 second flats