Sh2-155, The Cave Nebula

"natural" color version

H-alpha

Version with reduced stars
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Last night I shot a new 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.

There is three versions, first with "natural" colors and second with H-alpha only.

Third image is same color image but with reduced stars. The purpose of this image is

to show the nebulosity alone.

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Imaging data:
Camera, QHY8

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Filters,
Baader 7nm H-alpha, Baader 8,5nm O-III and Baader

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Optics,
Tokina AT-X 300mm @ f2.8

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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