u/kamik1979

Hi,

I am trying to get rid of a radial haze around stars. I am not sure what they are caused by. Collimation seems to be fine, I have checked and adjusted with a proper Cheshire.

My equipment:
- SW 200/1000mm Newtonian
- GSO 2" coma corrector (with an extension tube for proper backfocus)
- SW HEQ5
- Sony A6400 (camera)

Whole shot: https://imgur.com/a/HTH9tJw
Zoomed in on affected stars (red markings added in attempt to highlight the issue): https://imgur.com/a/yanDn8f

Help would be greatly appreciated.

Roughly 57min of exposure (low, but I wanted to use the last night before forecast storms, so oh well) in a Bortle 5 sky.

Equipment:

- SW Newtonian 200/1000mm

- SW HEQ5

- Sony A6400 (no mod)

Processed in Siril: standard preprocessing, separated stars and stretched separately, then recombined.

Camera: Sony A6400 (no mod),

Lens: Samyang 135mm f/2,

Mount: Skywatcher HEQ5,

Sky: Bortle 5, no moon.

Around 400 of 30 s subs pre-processed, stacked and post-processed in Siril with a pretty standard procedure. However due to moderate light pollution quadratic background extraction was applied already at sub level. Shot at f/2.8, ISO 400.

Visible near the upper right corner is the Crescent Nebula (NGC 6888). The halo around Sadr is a result of lens optics and I did not attempt to remove it. A reflection nebula near the lower left corner around 44 Cygni is also visible.