Sh2-155 The Cave Nebula

Sh2-155 (also designated 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, at an estimated distance of 725 parsecs (2400 light-years) from Earth.

Sh2-155 was first noted as a galactic emission nebula in 1959 in the extended second edition of the Sharpless catalogue, being a part of the much larger Cep OB3 Association. 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 is referred to as a globule (cataloged CB230) and over 2 light-years across. There are several stars embedded, whose emissions make the nebula shine in brownish colour.

Technical Data

Bortle Scale / SQM-L	Bortle 4/5 / --
Period	August 2015
Primary Scope	FSQ106 106/530
Camera	CCD KAF-8300
Mount	NEQ6
Total Exposure Time	6,5H
Composition	LHRGB
Location	Val Imagna (Bergamo) Italy