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Coathanger Cluster Cr399 (SS61 Ra).jpg

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The colourful region in and around the Coathanger asterism in Vulpecula the Fox. The grouping is not a star cluster per se, though it is catalogued as one, Collinder 399. It is also known as Brocchi's Cluster. A true star cluster, NGC 6802, is located at the east (left) end of the Coathanger, as the small clump of stars. The area is also rich in faint nebulosity, notably: the Sharpless 2-83 reflection nebula complex above the Coathanger, and the small, round Sharpless 2-82 emission and reflection nebula below the Coathanger. The large area of red emission nebula at bottom right is not catalogued or labelled in any of the star atlases I have, including the Millenium Star Atlas and Uranometria. However, the small round red "nebula" on the bottom edge of the large nebula is actually a highly reddened globular cluster, Palomar 10. This area of the Milky Way is rich in dark nebulas and absorbing dust, yellowing the fields.

This is a stack of 10 x 5-minute exposures through the SharpStar 61EDPH II refractor with its flattener/reducer at f/4.5 and the red-sensitive Canon Ra, though with no filter employed here. The mount was the little Star Adventurer GTi portable GoTo mount undergoing testing, and autoguided with the ZWO ASIAir and its little 30mm guidescope, with the Air also controlling the Ra and performing dithering moves between each exposure. The guiding worked very well. No darks or LENR were applied here, but the stacking averaged out the thermal noise hot pixels on this fairly warm autumn night, September 27, 2022.

All stacking and alignment with Photoshop. A mild Orton Glow effect added with Luminar AI, plus an application of PK Actions Dark Detail Hard action (a form of high-pass sharpening), two somewhat opposing effects -- i.e. fine sharpening plus overall softening. But the result does punch up the nebulosity, as does some luminosity masked curves adjustment layers from TK Actions and Lumenzia. Noise reduction was with RC Astro's Noise XTerminator.
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© Alan Dyer/AmazingSky.com
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Star Clusters, NGC/IC Objects
The colourful region in and around the Coathanger asterism in Vulpecula the Fox. The grouping is not a star cluster per se, though it is catalogued as one, Collinder 399. It is also known as Brocchi's Cluster. A true star cluster, NGC 6802, is located at the east (left) end of the Coathanger, as the small clump of stars. The area is also rich in faint nebulosity, notably: the Sharpless 2-83 reflection nebula complex above the Coathanger, and the small, round Sharpless 2-82 emission and reflection nebula below the Coathanger. The large area of red emission nebula at bottom right is not catalogued or labelled in any of the star atlases I have, including the Millenium Star Atlas and Uranometria. However, the small round red "nebula" on the bottom edge of the large nebula is actually a highly reddened globular cluster, Palomar 10. This area of the Milky Way is rich in dark nebulas and absorbing dust, yellowing the fields. <br /> <br /> This is a stack of 10 x 5-minute exposures through the SharpStar 61EDPH II refractor with its flattener/reducer at f/4.5 and the red-sensitive Canon Ra, though with no filter employed here. The mount was the little Star Adventurer GTi portable GoTo mount undergoing testing, and autoguided with the ZWO ASIAir and its little 30mm guidescope, with the Air also controlling the Ra and performing dithering moves between each exposure. The guiding worked very well. No darks or LENR were applied here, but the stacking averaged out the thermal noise hot pixels on this fairly warm autumn night, September 27, 2022. <br /> <br /> All stacking and alignment with Photoshop. A mild Orton Glow effect added with Luminar AI, plus an application of PK Actions Dark Detail Hard action (a form of high-pass sharpening), two somewhat opposing effects -- i.e. fine sharpening plus overall softening. But the result does punch up the nebulosity, as does some luminosity masked curves adjustment layers from TK Actions and Lumenzia. Noise reduction was with RC Astro's Noise XTerminator.