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M81, M82 Galaxy Pair



Scope: Celestron 9.25 Edge HD 235 mm at f/7, Location: DAA Observatory, Shelter Valley, CA, 22, 25 January and 15 February 2023, 

Exposure: Exposure:  Panel 1 - Lum 64 x 3 min (gain-140 2x2), Ha 44 x  5 min (gain-180 2x2), RGB 20 x 2 min (gain-121 2x2). Panel 2 - Lum 64 x 3 min (gain-140 2x2), Ha 46 x  5 min (gain-180 2x2), RGB - 20 x 2 min (gain-121 2x2)

Processing: Data Collection -  Sequence Generator Pro (as FITs).  Sub-frame calibration - Pixinsight (WBPP). Sub-frame  registration and integration (Average combine - Winsorized Sigma Clipping) - PixInsight (WBPP).  Mure Denoise - PixInsight. Deconvolution - BlurxTerminator (via PixInsight). Non-linear stretching and gradient removal - PixInsight.  Generation of starless nebulosity Luminance images for later processing - Star XTerminator. The RGB "stars only" image separately stretched, Luminance starless and mono stars only combine for luminance construction - PixInsight. RGB combine, RGB stretching, SpectroPhotometric RGB calibration (SPCC), and Luminance layering - PixInsight. Ha stack stretched - Starless version generated - Pixinsight. Mosaic By Coordinates and Gradient Merge Mosaic - PixInsight.  Final finishing  - Affinity Photo. Annotation - PixInsight, Aladin (Simbad), and Affinity Photo. This image is a  LRGB wide band image with Luminance layering and with Ha highlights screen blended into LRGB image.  Image panels  processed at 6248x4176 resolution. Final Mosaic Image size is approximately  6800x2276.

North is to the right in this image.  This is a two panel mosaic image. It shows M81 and M82 galaxies in relation to each other in space. M81 (SA(s)ab) is 11.8 million light years distant and M82 (I0 edge-on) is 12.1 million light years - M82 is also known as ARP 337. Five galaxies in this image have similar distances and radial velocities that put them into common groups  (M81, M82, LEDA 28759, PGC 28529, and UGC5336). Two  groups contain all five as members  ([TSK2008] 217 and [T2015] nest 101368).  There are a number of background galaxies and quasars (or candidates) in this field as well. Many of these are small or faint and can only be seen in the full size image. The furthest quasar visible in this image is SDSS J095752.57+693227.6 -  it has a redshift of 3.400 and a light travel time of 11.83 billion years (lookback). These objects and some of the brighter stars are identified in the annotated image. This image replaces an earlier image that can be seen in the Archives hereHorizontal FOV is approximately 78 arc minutes. Full size image scale is about .68 arcsec/pix.

Image center is located approximately - Equatorial 2000: RA: 9h 55m 40s Dec: 6921'28"


All images and content remain the property of Jim Thommes - copyright 2003 - 2023

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