Hemisphere:  Northern  ·  Constellation: Cepheus (Cep)
The Cave Nebula (Ha + RGB), 


            Scott Davis
The Cave Nebula (Ha + RGB)
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The Cave Nebula (Ha + RGB)

Technical card

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: Sequence Generator Pro  ·  DeepSkyStacker  ·  Photoshop CS6

Filters: Astronomik 6nm Ha Clip-In Filter  ·  One-Shot Color

Accessory: Robofocus

Dates:Aug. 5, 2015Aug. 11, 2015Aug. 12, 2015Aug. 14, 2015Nov. 6, 2015

Astronomik 6nm Ha Clip-In Filter: 65x600" (10h 50') ISO1600
One-Shot Color: 20x300" (1h 40') ISO1600

Integration: 12h 30'

Darks: ~15

Flats: ~40

Flat darks: ~40

Bias: ~40

Avg. Moon age: 25.76 days

Avg. Moon phase: 20.91%

Bortle Dark-Sky Scale: 6.33

Basic astrometry details

Astrometry.net job: 837664

RA center: 22h 54' 6"

DEC center: +62° 26' 56"

Pixel scale: 3.148 arcsec/pixel

Orientation: 178.619 degrees

Field radius: 1.029 degrees

Resolution: 620x384

Locations: My Backyard, Clovis, California, United States; Big Stump, Kings Canyon National Park, CA, United States


The Cave Nebula, catalogued as Sharpless 2-155 or Cardwell 9, is a very faint emission nebula in the constellation Cepheus. While extremely difficult visually in the best of telescopes, the pockets of gas, dust lanes, and even an area of reflection nebula make for a beautiful photographic target. Its distance is estimated to be approximately 2,400 light years from Earth.

RGB data was captured from Big Stump in Kings Canyon National Park. Hydrogen-Alpha data was captured from my backyard in Clovis, California.


Sky plot

Sky plot


The Cave Nebula (Ha + RGB), 


            Scott Davis