Sh2-155 (Cave Nebula) and VdB 155 in Cepheus

  Size: 1800 px      
© Velimir Popov & Emil Ivanov 2011 - 2017

Sh2-155 (also catalogued BN 529, LBN 110.11+02.44, Caldwell 9, or Cave Nebula) is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. Sh2-155 is an ionized H II region with ongoing star formation activity. The estimated distance of Sh2-155 is about 725 parsecs (2400 light-years) from Earth. The Cave Nebula lies at the edge of the Cepheus B cloud (part of the Cepheus molecular cloud), and is ionized by very young stars (less than 100,000 years old) from the Cep OB3 association. 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. This complex contains also LDN 1216 - a large dark nebula above Sh2-155 and VdB 155 - the blue reflection nebula just right of LDN 1216 (see mouseover). The illuminating star of VdB 155 is HD 216629 - a B2IV blue giant of mag. 9.37, which gives the bluish colour to the nebula.

Image details:


Center of field RA 22:55:55 (h:m:s)
Center of field DE +62:21:12 (deg:m:s)
Size 1.45 x 1.14 (deg)
Pixel scale: 2.03 (arcsec/pixel)
Orientation: Up is 90.9 degrees E of N
Charts and image details obtained from
Optic(s): ASA 12" Astrograph @ f/3.6 (Newton)
Mount: ASA DDM85 Standard
Camera: SBIG STL 11000 M
Filters: Luminance, Red, Green, Blue, Astronomik filters, Ha Baader filter
Dates/Times: 29 Oct, ,3 Nov. 2011
Location: IRIDA Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exp. Details: L:12x10min., R:8x10 min, G:7x10 min, B:8x10 min, Ha 10 x 15 min. Bin 1, Total Exposure Time - 500 min (8:20h).
More details: Dark and flat frames reduction
Processing: PixInsight / PS
Copyright: Velimir Popov and Emil Ivanov 2013 - 2017. All Rights Reserved
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