Dark Shark Nebula LDN 1235 (1 and 10 December 2021)
The Dark Shark Nebula is a dark nebula in the constellation Cepheus. It is composed of interstellar dust so thick that it hides the light of the stars behind it. Dark nebulae are often extremely faint and difficult to process to stand out against the background sky. The Dark Shark Nebula is no exception, and the challenge was enhanced for me by the limited exposure time (due to cloud cover), the light from the first-quarter moon (on the 10th December), and my neighbour’s security light, both of which contributed a severe gradient to the unprocessed image.
Hera image processing
I made this video about how I processed the Dark Shark Nebula using the software I’ve been writing, called Hera. As this video is just a demo of an early pre-release version of the software, and I still have a good many tools to add, I completed the last few steps of processing in Photoshop.
Image details
Frames
- 36× 300-s light frames (Gain 900) from 46 overall (best 80%)
- 9 frames from 1 December 2021; 37 frames from 10 December 2021
- 3 h total integrated exposure time from 3 h 50 min overall (best 80%)
- Full use of calibration frames (darks, flats, dark flats)
Equipment
- Explore Scientific ED 102 mm Apo f/7 refractor
- Revelation Adjustable Field Flattener
- Sky-Watcher EQ6-R PRO SynScan GOTO equatorial mount
- Altair Hypercam 294C PRO colour fan-cooled camera
- Pegasus FocusCube v2
- Altair 60mm guide scope
- Altair GPCAM2 AR0130 mono guide camera
- Hystou Rugged Fanless Mini PC i5 7260U
Software
- SharpCap 4.0
- PHD2
- DeepSkyStacker
- Hera 0.1.0
- Photoshop
- Topaz DeNoise AI
