NGC6888
Crescent Nebula and recently discovered bubble
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| Other names: |
Caldwell 27 | Van Gogh's Ear Nebula |
| Optics: |
Takahashi FSQ-106ED at f/5 |
| Mount: |
Mountain Instruments MI-250 w/Gemini on ATS pier |
| Camera: |
SBIG ST-10XME with CFW-10 and AstroDon narrowband filters |
| Exposure: |
640 minutes in 20 minute subexposures [ R (SII): 200 min, G (Ha): 240 min, B (OIII): 200 min ] |
| Accessories: |
Optec TCF-S Focuser |
| Location: |
Camp Oakes near Big Bear, CA [ RTMC Astronomy Expo ] |
| Date |
May 22-24, 2009 |
| Notes: |
Processing: Image acquisition and dark frame calibration (27 dark frames) in CCDSoft. Align in ImagesPlus. Bloom removal and color combine in MaxImDL/CCD. Levels, curves, sharpen, and crop in Photoshop. No flats.
Why the odd framing of the Crescent Nebula? I was attempting to capture the newly identified circular bubble near the Crescent. It's barely visible toward the top, right of center. I knew generally where to find Dave Jurasevich's bubble but I wasn't sure of the specific location so I positioned the Crescent as seen and shot away. Fortunately, it's in the frame.
See an alternate version with more emphasis on the Ha (green) channel.
Click the image for a larger version (1800 x 1200, ~2.4 MB).
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