Imaged Comet 12P/Pons-Brooks on the night of December 6, 2023 as it passed near the bright star Vega. The comet had an apparent magnitude (v) of ~9 and the coma had an apparent size of ~3 arcsec. This one was tough to process with both the comet and the super bright glow from Vega in the same frame...
More information on this comet and its close approach to Vega at:
https://spaceweather.com/archive.php?view=1&day=07&month=12&year=2023Imaged with a William Optics GT81 at F4.7 (382 mm focal length) using Flat6A II field flattener/0.8x reducer, UVIRcut filter, and ZWO ASI 533MC Pro.
Total integration time of ~30 minutes: 20 subs at Gain = 100 with an exposure time of 90 seconds.
Processing steps:1 - All images pre-processed using Pixinsight's weighted batch pre-processing script (WBPP) to perform calibration, debayering, and star registration. Batch processed using ABE to remove gradients from individual images.
2 - After some trial and error dealing with processing the comet and Vega in the same frame, I split all the images into two subs (one with the comet, one with Vega) in order to perform comet alignment.
3 - Comet images: First I integrated the star aligned images. Then I ran starXterminator to generate a stars only image. Next, I comet aligned the individual subs subtracting the star-aligned, stars only master to generate comet aligned, comet only images. I integrated the comet only images, then re-combined with the stars only master. This gave me a comet + stars image.
4 - Vega images: I simply integrated the Vega images.
5 - I registered the comet+stars and Vega images, then combined using gradient merge mosaic
6 - Additional processing on the final mosaic image: spcc, blurXterminator, noiseXterminator, histogram transformation using STF parameters, GHS2 stretch, ezhdr script
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