[Solar System] Submission 144607 – Peter Barnett

By: Peter Barnett

A headless comet C/2024 G3 (Atlas) captured from Christchurch on 20 January 2025. The comet passed very close to the sun, getting ten times closer to the Sun than the Earth does, however it did not survive for long after. Reports that the comet head had disintegrated started to appear on 19 and 20 January, so I headed out to capture my own image. I found this a difficult object to view and image, as the background sky was so bright, but also rapidly changing as twilight turned to darkness. The comet follows the same path as the sun so you need to be at a location that can see the sun set onto the horizon. Sun set was 9.07 pm and I first found the comet about 40 to 45 minutes later. At this point the sky was so bright a five second exposure was white and showed nothing, but a two second exposure did show the comet. As twilight ended, I had to keep increasing the exposure. This image was a small stack of the best images taken starting at 10.16 pm that best showed the comet tail. The last frame was taken at 10.23 by which time the comet was only four degrees above the horizon. Field of view of the final image is 3 degrees x 2 degrees.