I’m still processing images from last month’s imaging sessions and am finally getting around to Comet 67P/Churyumov-Gerasimenko images captured on January 23rd. Although Comet 67P passed perihelion in November, it was, and as of this writing still is, well placed for viewing in the evening sky.
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| This image of 67P consists of seven 240-second images stacked to produce a single image. Field of view 20×15 arcminutes. North is up. East is left.[1] | 67P moves across the sky over a 24-minute period. On this night, 67P was moving westward at 0.5 arcseconds per minute, or approximately one-half an arcminute per hour. Field of view 20×15 arcminutes. North is up. East is left.[2] |
On images captured during this session, I measured 67P’s magnitude as 12.25. By this time, the comet had faded considerably from its peak near magnitude 8.0 in November when it passed perihelion. In these images you can see a faint tail extending approximately 8 arcminutes to the west-northwest (north is up and west is to the right).
If you click on either of the two images, the larger image that appears in your browser may show dark artifacts in the upper left corner, lower left corner, and along the left edge of the image. You also may notice a faint bright glow in the upper right corner. Unfortunately, the dark frames I captured this session for calibrating my images were not done correctly. Thus, the ugly artifacts. Plain old operator error.
Notes:
1. January 23, 2022, 03:51:45-04:15:52 UT. Stack of seven images, each a stack of 2 frames at 120 seconds (total 240 seconds). Gain: 250. Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.
2. January 23, 2022, 03:51:45-04:15:52 UT. 24-minute, 7-image, animation sequence. Each image a stack of 2 frames at 120 seconds each (total 240 seconds). Gain: 250. Telescope: Meade SN-8 (203mm f/4). Camera: ZWO ASI224MC with UV/IR cut filter. Mount: Celestron CGEM.