Presenting Comet 12P/Pons-Brooks imaged in the evening after sunset on March 8, 2024, in Skull Valley, Utah, United States. As I understand it, this may have been after or during an outburst event. Whatever the case, this is the most interesting and dynamic comet I’ve ever imaged in terms of *waves hands at the thing* everything that’s going on here. You can hover over the image to see a starless-with-small-fuzzies version.
After four months of cloudy, cold winter nights, it was a delight to get out, and fun to see my buddies Jeff and Lester again. I missed this.
Hope you enjoy!
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License Creative Commons CC BY-NC-ND 4.0 DEED
Attribution to
James PeirceAcquisition DetailsI used my Esprit 120ED on my AM5 (chonky Burlebach tripod) along with my ZWO ASI2600MC Duo and an ASIAir Plus for computer. I started imaging the comet as soon as it was reasonably dark for a time with sequential images. (Next time, I’ll pause between images to improve rejection, or use mono RGB). 12P/Pons-Brooks was a very cooperative comet! The details did not shift rapidly and the comet did not move very quickly, so I was able to use a decent number of exposures.
Editing NotesPixInsight: Stacked with calibration frames using WBPP. Created comet-aligned images from debayered files using CometAlignmet, removed stars with StarXTerminator (batch edit), normalized with Normalize Scale Gradients, stacked with rejection to remove stars, GradientCorrection to remove gradient. Used CometAlignment with comet integration as operand and linear fit to subtract comet from star-aligned files created by WBPP, LocalNormalization, and integrated for stars-and-galaxies image.
Stars Image: Experimented with Drizzle-integrated image (with smeared comet) and comet-removed image and got better stars and color calibration on Drizzle image. GradientCorrection, BlurXTerminator (correct only) to improve stars (minor aberrations and light scatter from shooting through atmosphere), SPCC (saved RGB values for comet), mild noise reduction with NoiseXTerminator and mild saturation boost with GHS (both using their own luminance masks). Basic stretch from STF, additional adjustments to stretch and saturation with GHS, second masked noise reduction. Opened stars image in Photoshop and reduced color separation on stars from atmosphere using a carefully-configured application of Camera Raw Filter chromatic aberration correction and color noise reduction and also made slight color adjustment. Opened in Pix, removed stars with StarXTerminator, refined star intensity and size with curves adjustment.
Comet Image: Gradient removal with Dynamic Background Extraction (GradientCorrection damaged some faint desirable structure), BackgroundNeutralization, ColorCalibration to transfer color calibration from stars image as applied with SPCC, luminance-masked noise reduction with NoiseXTerminator, stretched and increased saturation with GHS, mild masked and blended application of LHE and HDRMT.
Adobe Photoshop: Opened comet image, refined with curves, and used tools assorted tools to clean up residual signal from brighter stars not fully rejected as well as fixing edge artifacts. Once cleaned up, pushed stretch a little more and refined colors, corrected some color noise in faint signal. Opened stars image (stars removed), touched up small fuzzies, and transferred them to comet image.
Wrap-up: Opened comet image and transferred stars with PixelMath (screen method), refining application with a couple curves adjustments to stars-only image. Opened again in Photoshop for final small touch-ups.
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