Sharpless catalog object, Sh2-155 in constellation Cepheus.

It's sometimes called the "Cave Nebula" doe the central formations shape,
I can't see the cave there though.
I shot three hours of H-alpha and one and half hours of O-III.
There is very litle of O-III there, but with extreme stretching of the data it was usable.
Image here is a narrowband color composition where H-alpha is Red and
O-III is Blue, Green color is synthesized from H-a and O-III channels.
Imaging data: Camera, QHY8
- Filters, Baader 7nm H-alpha, Baader 8,5nm O-III and Baader
- Optics, Tokina AT-X 300mm @ f2.8
- Exposures, 9X 1200s H-alpha, 4 X 1200 O-III + flats and bias
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Guiding, LX200 GPS 12" + PHD-guiding and Lodestar