12P/Pons-Brooks 2023-Sep-07 Dan Bartlett

Comet 12P/ Pons-Brooks from Sept 7, 2023. After the July 20, 2023 outburst causing the comet to brighten 4- 5 magnitudes, comet 12P/ has expanded to an oddly shaped object. I haven't been able to understand the cause of the background banding which is unfamiliar to this often used scope and camera. The WISE (w3) data for the image coordinates do show similar structures in the IR spectrum but unfortunately the IRSA search doesn't expand past one degree. Comet perihelion isn't projected to be until April 2024.

ASTROBIN: https://astrob.in/kcf0te/B/

Observational details:
Backyard setup
scope: C14 D = 356mm; fl =729mm; F# 2
camera: asi 2600mcP
exposure: 26 x300 sec
Seeing: 4/5
Transparency: 9/10
Observer: DEBartlett
Location: June Lake, California, USA


Image Info:
Projection ............... Gnomonic
Projection origin ........ [1409.212432 968.621748] px -> [RA: 17 21 59.057 Dec: +51 06 53.87]
Resolution ............... 2.127 arcsec/px
Rotation ................. -5.523 deg
Reference system ......... ICRS
Observation start time ... 2023-09-07 04:12:04 UTC
Observation end time ..... 2023-09-07 04:17:04 UTC
Geodetic coordinates ..... 119 04 46 W 37 46 30 N 2357 m
Focal distance ........... 729.32 mm
Pixel size ............... 7.52 um
Field of view ............ 1d 39' 52.5" x 1d 8' 36.9"
Image center ............. RA: 17 21 59.022 Dec: +51 06 54.06 ex: +0.095129 px ey: -0.014228 px
Image bounds:
top-left .............. RA: 17 26 58.582 Dec: +51 45 25.18 ex: +0.072559 px ey: -0.191664 px
top-right ............. RA: 17 16 17.811 Dec: +51 35 43.32 ex: +0.168897 px ey: -0.124951 px
bottom-left ........... RA: 17 27 32.776 Dec: +50 37 04.32 ex: -0.241309 px ey: -0.120307 px
bottom-right .......... RA: 17 17 07.582 Dec: +50 27 35.88 ex: +0.236492 px ey: +0.158116 px