M81 in Ursa Major



Scope: Celestron 9.25 Edge 235 mm at f/7, Location: DAA Observatory, Shelter Valley, CA,   3 Feb 2018  Camera: ST8300M (Baader LRGB filters)

Exposure: Exposure:  24 x 12 min (2x2 bin) exposure with IR/UV Block filter, 12 x 4.5 min (2x2 bin) RGB exposures.

Processing: Data Collection -  Sequence Generator Pro (as FITs).  Calibrated, stacked (Kappa Sigma Combine) - Deep Sky Stacker. LRGB channel registration, equalization - Astroart.  Curves, Levels, RGB combine - ImagesPlus. Luminance Layering, final stretch, and finishing  - Photoshop.  RGB calibration - eXcalibrator. This image is a  RGB combine with Luminance layering.  Color saturation in LAB color.  The IR/UV Blocking filter exposure stack was used for the luminance layer. High pass sharpening applied. Images processed at 3352 x 2532 resolution. Final Image size is approximately  2800 x 2100.

North is up in this image.   This field is M81 and the surrounding region. The irregular dwarf, UGC 5336, is left of M81 - it is a satellite of M81 and is thought to be the youngest nearby galaxy. M81 is an Active Galactic Nucleus (AGN) galaxy. It is well studied and cataloged. There are over 2,500 cataloged galactic objects within its confines  in the SIMBAD database - many are listed as "unknown" for object type. The annotated image shows the brightest globular cluster and brightest HII region. There are several distant background galaxies in this field as well.  The two bright stars below and to the right of M81 are really both double stars. BD+69 541A,B are an obvious double and are resolved in the image  at about 9.55 arc seconds separation. These are likely a pair  since they are also high proper motion stars with very similar velocity vectors. The other double is HD 85458A,B and is unresolved in the image. Their separation is less than a one arc second  These galaxies and  stars are identified in the annotated image.. This image replaces an earlier image that can be seen in the Archives hereHorizontal FOV is approximately 38 arc minutes.

Image center is located approximately - Equatorial 2000: RA: 09h 55m 33s Dec: +6904'00" 


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