Daily Archives: March 4, 2015

SH2-261, or Lower’s Nebula


SH2-261, or Lower’s Nebula, is a Hydrogen Alpha emission region  located in the upper area of Orion, near the Gemini constellation. Image covers about a same area as a full Moon. There is  no information about the distance of this hydrogen cloud, so we are not able to determine how large it is.

The nebula is named after amateur astronomers Harold Lower and his son Charles, who discovered this nebula in 1939 from a picture taken with their homemade 8 inch, f/1 Schmidt camera.

Imaging telescopes or lenses: Explore Scientific ED102 APO
Imaging cameras: Canon EOS Rebel T3i
Mounts: Celestron CGEM Hypertuned
Guiding telescopes or lenses: Orion ShortTube 80
Guiding cameras: Orion StarShoot Autoguider
Focal reducers: Astro-Tech AT2FF
Software: DeepSkyStacker,  Main Sequence Software Sequence Generator Pro,  Photoshop CS6
Filters: Astronomik 6nm Ha Clip-In Filter,  One-Shot Color
Accessories: Robofocus,  Home Made Peltier Cooler for T3i
Resolution: 2000×1651
Dates: Feb. 14, 2015,  Feb. 16, 2015,  Feb. 17, 2015,  Feb. 19, 2015,  Feb. 21, 2015,  Feb. 23, 2015
Astronomik 6nm Ha Clip-In Filter: 68×600″ ISO1600
One-Shot Color: 41×300″ ISO1600
Integration: 14.7 hours
Darks: ~22
Flats: ~40
Flat darks: ~40
Bias: ~40
Avg. Moon age: 18.95 days
Avg. Moon phase: 12.93%
Bortle Dark-Sky Scale: 6.33
RA center: 92.265 degrees
DEC center: 15.722 degrees
Pixel scale: 2.170 arcsec/pixel
Orientation: 179.949 degrees
Field radius: 0.782 degrees
Locations: My Backyard, Clovis, California, United States; Big Stump, Kings Canyon National Park, CA, United States
Author:  Scott Davis

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