Hemisphere:  Northern  ·  Contains:  Sh2-155
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Cave Nebula Sh2-155 HaLRGB, 


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Cave Nebula Sh2-155 HaLRGB

Technical card

Imaging telescopes or lenses: Skywatcher Explorer 200PDS

Imaging cameras: QHYCCD QHY9M

Mounts: Skywatcher NEQ6 PRO Synscan

Guiding telescopes or lenses: Skywatcher 9x50 finderscope

Guiding cameras: QHYCCD QHY5-III 178 C

Focal reducers: Baader MPCC Mk III

Software: Photoshop  ·  Pixinsight

Filters: Baader Red 2"  ·  Baader L 2''  ·  Baader Green 2"  ·  Baader Blue 2"  ·  ZWO Ha 7nm

Accessory: QHYCCD QHY 2" Filter wheel  ·  Seletek Armadillo

Dates:Sept. 10, 2020

Baader Blue 2": 13x300" -30C bin 1x1
Baader Green 2": 15x300" -30C bin 1x1
ZWO Ha 7nm: 14x300" -30C bin 1x1
Baader L 2'': 23x300" -30C bin 1x1
Baader Red 2": 14x300" -30C bin 1x1

Integration: 6.6 hours

Flats: ~20

Bias: ~100

Avg. Moon age: 22.25 days

Avg. Moon phase: 48.89%

Astrometry.net job: 3843094

RA center: 22h 56' 52"

DEC center: +62° 42' 30"

Pixel scale: 1.105 arcsec/pixel

Orientation: -55.719 degrees

Field radius: 0.602 degrees

Resolution: 3165x2320

Locations: Puolivälinkangas - Oulu, Oulu, Finland

Data source: Backyard


Getting more Sharpless, this one was hard, taking 3 nights.

Sh2-155 (also designated Caldwell 9, Sharpless 155 or S155) is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. It is widely known as the Cave Nebula, though that name was applied earlier to Ced 201, a different nebula in Cepheus. Sh2-155 is an ionized H II region with ongoing star formation activity,[1] at an estimated distance of 725 parsecs (2400 light-years) from Earth.[2][3]

Sh2-155[4] was first noted as a galactic emission nebula in 1959 in the extended second edition of the Sharpless catalogue,[5] being a part of the much larger Cep OB3 Association.[5] Although Sh2-155 is relatively faint for amateur observation, some of its structure may be seen visually through a moderately sized telescope under dark skies.[6][7]

Sh2-155 lies at the edge of the Cepheus B cloud (part of the Cepheus molecular cloud), and is ionized by young stars from the Cep OB3 association.[8] It has been suggested that radiation from the hot O-type star HD 217086 is compressing the region, triggering the formation of a new generation of stars.[9] A study of the region's young stellar objects by the Chandra X-ray Observatory and Spitzer Space Telescope shows a progression of stellar ages in front of the cloud, supporting the hypothesis of triggered star-formation.[10][11]



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  • Cave Nebula Sh2-155 HaLRGB, 


  • Final
    Cave Nebula Sh2-155 HaLRGB, 



Sky plot

Sky plot


Cave Nebula Sh2-155 HaLRGB,