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Messiers 81 and 82 with NGC 3077


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About this observation
John Hughes
Time of observation
29/03/2020 - 23:00
Messier 81
Observing location
North Norfolk, UK
William Optics Z103 APO Refractor
ZWO ASI1600mm Pro Cool camera
William Optics 50mm Guidescope
ZWO ASI290mm mini Guide Camera
L 19 x 120s & 98 x 60s Bin 1x1 R 10 x 60s Bin 2x2 G 10 x 60s Bin 2x2 B 15 x 60s Bin 2x2 Ha 46 x 300s Bin 1x1

This is John's first submission to the Deep Sky gallery, and what a great image.  He reports some issues with artefacts and also that this was his first attempt at combining LHaRGB and the calibration of the lights with flats, darks and dark flats. Warren A. Keller, author of Inside PixInsight was very helpful with questions on the "PixInsight for Beginners Group" on FaceBook.

Ron Brecher's presentation on The Astro Imaging Channel on YouTube helped with a dust mote that wasn’t entirely cleared by the master flat (Pixel Math section “if the pixels are this, do this, or do nothing”). Using this method helped him to slightly raise the brightness of pixels in the offending area leaving the rest of the image untouched.

The artefact? Well, as hard as John tried he couldn’t remove a light-ish smudge to the left of Messier 81, but checking on the Astrobin website showed that this was in fact galaxy PGC28757!

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