Pacman Nebula

[GraemeH]

Second ever narrowband image for me, so I'm hoping for some constructive feedback.

This was captured in a single session on January 2 between around 8pm and midnight in my Bortle 5 back garden with the ambient temperature around 1°C

Mount:  HEQ5
Imaging scope:  Evostar 72ED
Flattener:  OVL non-reducing flattener
Other accessories:  Gerd Neumann CTU between flattener and filter wheel, adjusted using N.I.N.A.'s Hocus Focus routine
Imaging camera:  QHY294M Pro cooled to -10°C
Filters:  Antila EDGE series 4.5nm SHO and Antlia V Series LRGB (all 36mm) in QHYCFW3M wheel
Guiding:  ASI178MC and Skywatcher 9x50 finder
Subs:  12 x 300" for SII, Ha & OIII, 40 x 15" for R, G & B for stars

My subs were calibrated with darks but no flats, because I'm having difficulties with reflections in my narrowband flats - I have ordered some filter masks that appear to have been successful for others experiencing the same issues with very similar gear.  APT used for image acquisition, APP for calibration and stacking, Starnet++ V2 and Photoshop for processing.  The starless narrowband stacks were processed as HaSHO with a lot of selective colour adjustment to get something like the Hubble Pallet, and then the RGB star layer added after using a colour preserving arcsinh stretch.

Hoping for some pointers for any areas I can look to improve for future images (addition of flats is obvious and will be addressed soon).

Thanks for looking.

[MartinB]

This is a lovely image.  It looks dark and moody on account of the low black point.  I had a look in PS and the average background value was 14.  I think this is too low unless you are using it to cover up some background cosmetic issues.  I think a background value of 25 would show a little more outer nebulosity and the image would appear a little bit less "constrained".

[GraemeH]

4 hours ago, MartinB said:

This is a lovely image.  It looks dark and moody on account of the low black point.  I had a look in PS and the average background value was 14.  I think this is too low unless you are using it to cover up some background cosmetic issues.  I think a background value of 25 would show a little more outer nebulosity and the image would appear a little bit less "constrained".

Martin, thank you very much for your kind comments. You're completely right about the dark background - I did that to hide the fact that I can't get my flats to correct properly due to some strange reflections. I think I'm going to try again though because I can't help thinking that poor flats must still be better than no flats. 

[SiriusDoggy]

I'm curious if you dithered while capturing your data? I'm seeing some consistent vertical pattern noise when viewing the image at full size. Not sure if it's walking noise or something else.

Otherwise, very nice. I like the colors.

[GraemeH]

44 minutes ago, SiriusDoggy said:

I'm curious if you dithered while capturing your data? I'm seeing some consistent vertical pattern noise when viewing the image at full size. Not sure if it's walking noise or something else.

Otherwise, very nice. I like the colors.

I was dithering every frame during this capture, with a dither distance around 20 pixels on the main camera.  I don't see the pattern noise you mention, but I'm very much aware that I might just not know what I'm looking for.