Image Description and Details :

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. 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.

Copyright: Sergiy Vakulenko

The Cave Nebula (Sh2- 155 or Caldwell 9) is an emission nebula of the Cepheus constellation.
It is a weak light nebula and very diffuse in a greater complex of nebula containing dark emission, reflection and nebulosity. It is located in the constellation of Cepheus and is about 2400 light years from Earth.
Acquisitions with NINA
344 x 300 s i.e. 28 H40
ASKAR 400 bezel
ASI200MC
SIRIL stacking
Pixinsight and Photoshop treatment

Copyright Fred Lamagat

The Cave Nebula lies in the constellation Cepheus about 2,400 light years away, pretty close in cosmic terms. The “cave” has a bright rim ionized by the hot blue-white stars in the vicinity. The main “cave” structure is 10 light years across and is catalogued as Sharpless 155 (Sh2-155) and also as Caldwell 9 (the Caldwell catalogue was compiled by Sir Patrick Moore, and named for his mother’s maiden name). Near the lower left corner of the image is a blue reflection nebula, vdB 155. The Cave Nebula region makes a nice natural colour image, highlighting red emission nebula, blue reflection nebulae, dark nebulae and many colourful stars. I’ve also imaged the Cave Nebula before at higher resolution; that image was publishedin the April 2016 issue of Sky and Telescope.

Tekkies:
Acquisition, focusing, and control of Paramount MXmount, with TheSkyX. Focus with Optec DirectSync motor and controller. Unguided. Automation with CCDCommander. Equipment control with PrimaLuce Labs Eagle 3 Pro computer. All pre-processing and processing in PixInsight. Acquired from my SkyShed in Guelph. Average transparency and seeing. Data acquired March 2-14, 2021 in a mostly moonless sky.

Sky-Watcher Esprit 150 f/7 refractor and QHY 16200-Acamera with Optolong H-alpha, O(III) and S(II) filters

Ha: 49 x 10m = 8hr10m
O3: 47 x 10m = 7hr50m
S2: 45 x 10m = 7hr30m

Total: 23hr30m

Copyright: Ron Brecher

Image Description and Details : Sh2-155 or Sharpless 155 is a diffuse nebula in the constellation Cepheus, within a larger nebula complex containing emission, reflection, and dark nebulosity. Images showing a curved arc of emission nebulosity corresponding to a cave mouth (roughly center of image) gives rise to the popular moniker "Cave Nebula". Sh2-155 is an ionized H II region with ongoing star formation activity, at an estimated distance of 2400 light-years from Earth.

Capture info:

Location: Orion’s Belt Remote Observatory, Mayhill NM, USA
Telescope: Takahashi 180ED reflector
Mount: Paramount MX+
Camera: SBIG STXL 16200
Data: 4.75,4.25,4,4.75,4.5 hours LRGB , Ha respectively
Processing: Pixinsight



Copyright: David Doctor