Sh 2-157 (Lobster Claw Nebula), NGC 7635 (Bubble Nebula),…

Lobster Claw Nebula, Bubble Nebula, Northern Lagoon Nebula
Lobster Claw Nebula, Bubble Nebula, Northern Lagoon Nebula

Huge HII region in Cepheus and Cassiopeia. Massive stars illuminate surrounding gas clouds. Wolf-Rayet stars power the blueish central part of the Lobster Claw and a massive star blows up the bubble, which is nothing else but a shockwave generated by fast stellar winds. The open star cluster just on the top in the center has a funny form … like the tip of an arrow.

The following shows two cropped parts: the Bubble Nebula and the Northern Lagoon Nebula.

Bubble Nebula
Bubble Nebula
Northern Lagoon Nebula
Northern Lagoon Nebula

Acquisition Details

Scope: Borg 90FL/500 with 1.08x Flattener
Filter: IDAS NBZ
Camera: ZWO ASI 2600MC Pro
Mount: Skywatcher HEQ5 Pro
Guiding Scope: MiniBorg 50
Guiding Camera: ZWO ASI 290MM
Guiding Software: PHD2
Acquisition Software: APT
Light Frames: 90x300sec in two nights
Flats, Dark Flats, Bias, Darks
Camera settings: Gain 100, Offset 20
Bortle 4-5, no moon
Acquisition Dates: July 05, 2021, July 09, 2021


Imaging & Stacking: PixInsight
Denoise: Topaz AI Denoise
Star halo removal: Gimp

The following is only a rough list of workflow steps used.
I tried so many variants, that I cannot list it here.
The crops are processed differently: stars were not extracted but simply reduced by using a custom star mask and Morphological Transformation.

The main picture follows approximately this workflow: