I finally had some time over my Christmas break to process (some of) my comet data, including the wide field images I took on Sunday, October 26, 2025 from the darker (Bortle 4) skies of Sargent, Texas.  

I miscalculated the direction of the comet motion and initially set up the camera with a 24 mm lens (very wide field, 53 deg by 35 deg) looking towards the sunset to get a lovely gradient of color.  Then, after it got dark, I took a series of images of the stars, about 13 minutes worth.  I didn’t take more data because I decided to move the camera to get a better framing.  The comet is in this image, but I had to circle it because it is so dim and doesn’t have an obvious tail.  You can see that it is below a triangle of stars, the Serpent’s head in the Serpens Caput (Serpent Head) constellation.

I took additional data with the 24 mm lens with a better framing, about 33 minutes worth.  I didn’t take more data because I wanted to switch to a different lens.  Happily, the comet is clearly visible in this image; no circling needed!  And the triangle of stars is still visible as well.

I took additional data with an 85 mm lens (15 deg by 10 deg field of view), about 11 minutes worth.  I cropped this image, so it is an even smaller field of view, again with the comet clearly visible along with the triangle of stars above it.

All of the pictures with the camera were taken using just a tripod (no tracking mount), so I had to do a fair bit of processing to remove the star trails in the data (BlurXterminator is a great tool for this), and I had to process the comet separately from the stars to keep it from smearing since is moving relative to the stars.

Finally, while I was taking pictures with the camera on a tripod, I was also taking pictures with my small telescope with a 430 mm focal length and a 1.8 by 1.2 degree field of view, about 45 minutes worth.  Of course the comet and its tail is amazingly obvious here, and I could see its tail changing over the course of the evening.  I’m working on making a movie of that, stay tuned!

Which version do you like the best?

Camera geek info – 24 mm sunset image:

• Canon EOS 60D in manual mode set at f/8, 10 second exposure, ISO 400
• Sigma 24-70 mm f/2.8EX lens, set at 24 mm, manual focus
• Tripod
• Intervalometer 

Frames – 24 mm sunset image:

• October 26, 2025
  • 80 10 second lights
  • 30 1/2500 second flats
  • Matching darks and dark flats from library

Camera geek info – 24 mm night image:

• Canon EOS 60D in manual mode set at f/2.8, 20 second exposure, ISO 400
• Sigma 24-70 mm f/2.8EX lens, set at 24 mm, manual focus
• Tripod
• Intervalometer 

Frames – 24 mm night image:

• October 26, 2025
  • 100 20 second lights
  • 30 1/2500 second flats
  • Matching darks and dark flats from library

Camera geek info – 85 mm night image:

• Canon EOS 60D in manual mode set at f/2.5, 6 second exposure, ISO 800
• Canon EF 85 mm f/1.8 lens at f/2.5 manual focus at infinity
• Tripod
• Intervalometer 

Frames – 85 mm night image:

• October 26, 2025
  • 110 6 second lights
  • 30 1/2500 second flats
  • Matching darks and dark flats from library

Camera geek info – telescope:

• William Optics Zenith Star 73 III APO telescope
• William Optics Flat 73A
• ZWO 2” Electronic Filter Wheel
• Antila RGB filters
• ZWO ASI183MM-Pro-Mono camera
• William Optics Uniguide 32MM F/3.75
• ZWO ASI220MM-mini
• ZWO ASiair Plus
• iOptron CEM40
• Sargent, Texas Bortle 4 skies

Frames – telescope:

• October 26, 2025
  • 16 60 second Gain 150 R lights 
  • 30 0.05 second Gain 150 R flats
  • 15 60 second Gain 150 G lights 
  • 30 0.02 second Gain 150 G flats
  • 17 60 second Gain 150 B lights (16 for stars)
  • 30 0.02 second Gain 150 B flats
  • Matching darks and flat darks from library