The Cave Nebula
Sh2-155 • Emission nebula • Cepheus • 2400 light-years from Earth
🔭
Askar FRA400
📷
ZWO 2600MC Pro
🌃
Bortle 8
⏱️
18 hours
🗓️
Nov & Dec 2021
Overview
The Cave Nebula, also known as Sh2-155, lies around 2400 light years from Earth in the constellation Cepheus. It’s a complex star forming region where intense radiation from nearby hot, young stars compresses surrounding gas and dust. This process triggers successive waves of star formation, carving dark cavities and bright emission fronts that give the nebula its distinctive appearance in long-exposure astrophotography.
Background
This was the most difficult image for me so far. I worked at the editing all day before I finally had something I was happy with — the 7th version! Part of the reason it was so tough is because of the high noise levels. I cut this project short at 18 hours because brighter winter targets are getting high in the sky, and I want to move onto them. Also, the integrated shot had banding issues, which I’ve never had before. I had a tricky time removing them until I discovered that PixInsight has a utility called CanonBandingReduction that fixed it in literally three seconds!
I normally crop my images in at least a little, but during editing it was obvious I’d captured a fair amount of surrounding nebulosity not often seen in images of the Cave Nebula. So, I kept it wide.
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Explore the field
Objects in this field 20 objects
20 objects
No matching objects.
- Cave NebulaSh2-155
- HII regionAlso catalogued as C 9 · LBN 529
- ASCC 125
- Open cluster
- Sh2-154
- HII regionAlso catalogued as LBN 521
- UBC 178
- Open cluster
- Gulliver 19
- Open cluster
- FSR 0416
- Open cluster
- vdB 155
- Reflection nebulaAlso catalogued as LBN 524 · DG 188
- FSR 0406
- Open cluster
- LBN 522
- HII region
- NGC 7419
- Open clusterAlso catalogued as Cr 453
- FSR 0404
- Open cluster
- LDN 1218
- Dark nebula
- LDN 1216
- Dark nebula
- LDN 1215
- Dark nebula
- LDN 1224
- Dark nebula
- LBN 527
- HII region
- LDN 1212
- Dark nebula
- LDN 1210
- Dark nebula
- LDN 1211
- Dark nebula
- LDN 1220
- Dark nebula
About the labels and credits
Positions and outlines are calculated from a plate solution of this photograph. Outlines are catalogue guides and may not follow every visible filament. Additional catalogue objects may be faint or indistinct in this exposure.
Plate solving and annotation data: SkySolver, by Dominik Sito. Stars: Gaia DR3 and Hipparcos (ESA). Deep-sky data: OpenNGC © Mattia Verga (CC BY-SA 4.0), SIMBAD and VizieR (CDS). Names: Wikipedia (CC BY-SA 4.0) and IAU WGSN. Catalogue overlay adaptations, including styling and selected display names, are shared under CC BY-SA 4.0. Photograph © Lee Pullen.
Kit list
This is the equipment I used to capture the image.
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Telescope: Askar FRA400
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Camera: ZWO ASI 2600MC Pro
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Guidescope: William Optics 32mm Slide-Base Uniguide
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Guidecam: ZWO ASI 120MM Mini
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Control: ASIAIR Plus
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Filter: Optolong L-eXtreme
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Example source data
Here’s an example single subframe and freshly integrated stack, just with simple stretches applied.
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Astounding! Your “slider” comparison makes it look like magic. With 120 second subs and fast f/5.6 you probably use no gain on the camera for benefit of maximum dynamic range?
Thanks! I always use Gain 100 (set via the ASIAIR Plus).