M27 through multiple bands, bit of exotic imaging

[riklaunim]

Images were made with an Omegon veTEC 432 M camera (IMX 439, 9um pixels), Bresser 200/800 f/4 Newtonian, and Explore Scientific Coma Corrector.

Around 20 x 120s frames were stacked for each image. Flat/dark, Graxpert to limit gradients aside from some weird reflection-like ones...

Theory and details on https://rkblog.dev/posts/astronomy/m27-nebula-in-various-bands/

CLS-HSI (LRGB type image):

H-alpha/IR/CLS: IR on green will show stars hidden by dust or emission from the nebula (check how some stars are brighter here than above):

H-alpha / Neutral oxygen 630nm / [He II] 587nm:

Some nebulae can realistically use [O I] and [He II] emission lines for imaging although they won't be as bright as the more popular ones and require custom filters.

The infrared wider band can be handy more often to go through the dust in a wider range of nebulae.

Channel shots:

Astronomik CLS-CCD:

Baader [O III] standard filter:

Baader H-alpha standard filter:

Optolong [S II]:

Astronomik ProPlanet 807 - infrared, skipping all major emission lines as well as going through dust more easily:

 

[He II] custom filter with halo from either light pollution or the filter itself (same wavelengths as sodium lamps):

 

[O I] neutral oxygen 630nm:

Astrodon UVenus:

 

Old SCT C11 images:

[O I]:

 

[He II]: