Dark Cloud in Orion in front of read emission nebula IC 434. Left to bright star Alnitak the so called Flame Nebula or NGC 2024.

This image shows originally very bright halos around bright stars caused by the IDAS NBX filter, which was very bad to this respect. Meanwhile IDAS has released NBZ as a better replacement … and it is really better.

Acquisition Details

Scope: Borg 90FL/500 with 1.08x Flattener
Filter: IDAS NBX
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: 29x180sec
Flats, Dark Flats, Bias, Darks
Camera settings: Gain 100, Offset 20
Bright moon (3/4) during acquisition
Bortle 4-5
Acquisition Date: Dec 26, 2020

Processing

Stacking Software: DSS
Imaging: PixInsight

I tried different processing techniques and ended up with extracting color channel, combine green and blue channel, stretch using range masks in the GB combination, using starnet to extract stars from channels separately, treat halos amanually using clone stamp tool, using red channel as luminance and add reduced stars in the and.

The following is an earlier processing result with Gimp instead of PixInsight. Clearly visible here the bright halos and much less structure in the emission nebula behind. Lack of experience at that time …