Sharpless 2-188 Planetary Nebula in Cassiopeia

Sharpless 2-188 Planetary Nebula in Cassiopeia

Semeis 22

Constellation: Cassiopeia
Ra: 01h 30m 40s
Dec: +58d 22m
Distance: 2,800 light years
Image Size: 35' x 35'
North: Right



Sharpless2-188 is an old planetary nebula (PN) in the Constellation of Cassiopeia at RA 01h 30m 40s and DEC +58d 22m. It is also known as Semeis 22. It is categorized as Type Cf PN , which is an extreme example of a crescent-shaped structure where the morphology has been significantly modified by interaction with the interstellar medium (ISM). It is approximately 9′ in diameter with north is toward the right. The brighter part of the crescent has filamentary structure and is a mixture of strong H-a and OIII emissions. It is about 2800 light years distant, but these distance estimates have very large uncertainties. The central star is moving through the ISM at 125 km/s. The structure does appear continuous so that it is not an open crescent, albeit much fainter on the northern side. There is a "tail" extending toward the lower right of the frame about as long as the diameter of the PN. For comparison, you can compare my result (0.4m telescope) with high-resolution image from the 4-meter Mayall telescope at Kitt Peak

Exposure: ~15hrs Total: 7hrs H-a, 6.5hrs OIII, 75 min RGB
Telescope: 16
Mount: Software Bisque Paramount ME
Oag: Astrodon MonsterMOAG
Acquisition: CCDAutoPilot4
Calibration: CCDStack2
Observatory Site: Sierra-Remote Observatories, Shaver Lake, CA
Camera: Apogee U16M
Filters: Astrodon Gen 2 RGB, 3nm H-a, OIII
Guider: SBIG ST-402
Camera Operation: MaximDL5.15
Processing: Photoshop CS5 Extended
Image Date: 07/09/2011 - 08/21/2011

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