An image with some unusual colour contrasts for a deep-sky image — with blue Bellatrix, a green comet, and the huge red Lambda Orionis nebula. This is
An image with some unusual colour contrasts for a deep-sky image — with blue Bellatrix, a green comet, and the huge red Lambda Orionis nebula. This is Comet ATLAS (C/2020 M3) seen here as the green glow above the bright blue star Bellatrix in the shoulder of Orion, and approaching the large diffuse red nebula surrounding the “head” star of Orion, Lambda Orionis. aka Meissa. The large nebula complex is catalogued as Sharpless 2-264. At right, above the comet, is the smaller emission and reflection nebula catalogued as vdB (vandenBurgh) 38. The sparse star cluster surrounding Lambda Orionis is Collinder 69. This was the night of November 15/16, 2020, with the comet moving rapidly northward a day after its closest approach to Earth and three weeks after its perihelion, or closest approch to the Sun. On the next nights the comet would have been within the nebula. This is a stack of 8 x 8 minute exposures without a filter, blended with 6 x 15-minute exposures through an Optolong L-Enhance narrowband nebula filter, to bring out the faint nebulosity. The comet image itself is from just one of the filtered frames layered and masked to reveal just the comet. But even in the single 15-minute exposure its image trailed slightly as its motion was quite rapid. I used a filtered shot for the comet as its green/cyan glow did pop out more than in the unfiltered shots, though the more usual cyan colour of a comet has been altered a little by the narrowband filter and its bandpass of the green OIII lines. All were with the William Optics RedCat 51mm astrograph at and with the Canon EOS Ra, with the filtered shots at ISO 3200 and unfiltered shots at ISO 800. Images were autoguided, with dithering, using the Lacerta MGEN3 stand-alone autoguider. I also used its polar alignment routing this night to refine the mount’s polar alignment and it seemed to work! All images stacked, aligned and blended with Photoshop.
Size: 5400px × 3603px
Photo credit: © Alan Dyer / VWPics / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: /2020, astrograph, atlas, autoguider, bellatrix, canon, collinder, comet, cr69, emission, eos, galaxy, green, lambda, m3, meissa, mgen3, nebula, optics, orion, orionis, photoshop, ra, redcat, reflection, sh2-264, sharpless, stacking, vandenburgh, vdb38, william
