Cave Nebula

The Cave Nebula is a diffuse nebula in the constellation of Cepheus, within a larger complex of nebulae containing emission, reflection and dark nebula.


recording data

object SH2-155
date of recording
September 3, 11, 12 and 13, 2017
exposure 20.8 h, H-alpha: 678x100", OIII: 69x100"
teleskope Celestron RASA F2.2
focal lenght 620mm
filter Baader f/2 Highspeed 2" H-Alpha, Baader f/2 Highspeed 2" OIII
camera ZWO ASI1600mmc
guiding 250mm guide scope, MGEN
mount Celestron CGE pro
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AstroBin Image of the day (IOTD) 09/20/2017 Link >

HD 217086 makes pressure

Sh2-155 is an ionized H-II region with continuous star formation activity at an estimated distance of about 2,400 light years from Earth. The Cave Nebula was first mentioned in 1959 as a galactic emission nebula in the extended second edition of the Sharpless catalogue. Although Sh2-155 is relatively weak for amateur observations, part of its structure can even be seen visually through a medium telescope under a very dark sky.


Sh2-155 is located at the edge of the Cepheus B cloud (part of the Cepheus molecular cloud) and is ionized by young stars of the Cep-OB3 association. It is believed that the radiation of the hot O star HD 217086 compresses the gas of the region and triggers the formation of a new generation of stars. A study by the Chandra X-ray Observatory and the Spitzer Space Telescope on the young stellar objects in the region shows an increase in the age of stars in front of the cloud and thus supports the hypothesis of star formation in this area triggered by HD 217086.

Baerenstein Observatory

private observatory
Marcel Drechsler





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