Newbie question

[AstroRookie]

Hello,

I took a shot of M13 as a first test of my new orion 8 f/3.9. I have a couple of questions about the final result.

Equipment list:

• orion 8 f/3.9
• mount skywatcher eq6r-pro
• canon 500d - astro-modded by me
• 40 exposures of 90 seconds and 40 darks
• 200 bias
• 200 flats
• capture software: nebulosity4
• guide camera: zwo asi120mm
• guide scope: svbony 20 (80mm - 400mm)
• guide software: phd2

Processing:

• siril preprocessing: align/callibrate/stack)
• siril post-processing: green nois reduction/ photometric noise reduction (very cool!)/deconvolution

Result:

I attached a screenshot of siril (as the tif or jpg export did not show these "problems")

My questions:

• after preprocessing, I still have 2 problems (see the marked areas); what can be the cause of that? Are my flats not "correct"? The big mark, is a spot on the sensor, that is the "collateral damage" of me removing the Ir-cut filter. The other mark must be an other issue, I don't know so far
• the right part of the picture, shows some sort of glow; there was no moon during capturing; I live in a bortle class 5 area, but street lights are dimmed after midnight, till 05:00am and shots were taken around 01:00am. what can cause this glow

Other remarks are very welcome - I hope to learn from it.

Thanks in advance,

AstroRookie

[wxsatuser]

The glow could still be some sort of LP or just a sky gradient, should not be a problem as such.

The marks, are they just dirt or physical damage?

[AstroRookie]

4 hours ago, wxsatuser said:

The glow could still be some sort of LP or just a sky gradient, should not be a problem as such.

The marks, are they just dirt or physical damage?

Hello Mike,

the big one on the right below, is dirt I guess and hope; it appeared after I modded the camera. When I used the built in sensor cleaning feature, it's shape changed, so that makes me think it's dirt (I will have it checked and hopefully cleaned by a profession photographer). The other one, I don't know where that comes from, to be investigated. Thanks for your input!

AstroRookie

PS: Nice pictures on your wordpress space