British Astronomical Association
Supporting amateur astronomers since 1890

Secondary menu

Main menu

BAA Gallery Deep Sky Galaxies
Image search

Messiers 81 and 82 with NGC 3077

Image

Expand image

About this observation
Observer
John Hughes
Time of observation
29/03/2020 - 23:00
Object
Messier 81
Observing location
North Norfolk, UK
Equipment
William Optics Z103 APO Refractor
ZWO ASI1600mm Pro Cool camera
William Optics 50mm Guidescope
ZWO ASI290mm mini Guide Camera
Exposure
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
Tags
Like This Image
Share

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!

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please contact the webmaster.