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PLN85+4.1 (HII Region)
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Image Details:
- Camera: SBIG ST-2000XM
- Mount: Astro-Physics 1200GTO
- Scope: AP Starfire 160EDF APO Refractor
- Configuration: Prime Focus
- Additional Optics: n/a (Prime)
- Filter: Astrodon LRGB I-Series Filters
- Effective Focal Length: 1200mm
- Effective Focal Ratio: f/7.5
- Exposure: 9 × 32min @ -20°C (Hα); 8 × 8min @ -20°C (RGB)
- Total Exposure: 8hrs, 0min
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- Date: 7/23/2010 (Hα), 8/4/2010 (RGB)
- Location: Saratoga, CA, USA
- Acquisition: CCD Commander
- Focus: FocusMax
- Dithering: CCD Commander
- Guiding: Self Guided
Processing:
- IRIS: Registration, gradient removal
- JimP: Dark subtraction, Flat field, Kappa-Sigma Stacking, White balance, ASINH stretching
- Photoshop: Hα and RGB combining, JPG conversion
Image Description:
This is PLN85+4.1, an HII region in the constellation of Cygnus. I thought this was a Planetary Nebula, cuz that’s what TheSky said it was, but upon further review and research, including Anthony Ayiomamitis’ excellent image and writeup, it's just a glowing cloud of HII. Oh well. Hα and RGB combined in Photoshop using the “Lighten” method, which worked better than the other methods I tried. Mouse over for the Hα-only version. A higher-resolution image is also available. North is up.