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Old 21-04-2021, 11:13 AM
Startrek (Martin)
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Startrek is offline
Join Date: Dec 2017
Location: Sydney and South Coast NSW
Posts: 4,961
Originally Posted by Zuts View Post
I recently spent 3 nights at Wiruna under dark skies. Amongst other things I shot M104. This is the last object from that weekend.

M104, The Sombrero Galaxy.

19 by 300 sec, Darks, Flats, Bias
ASI 2600 MC, No filters
Esprit 120 @F7

Bortle 2 sky

Processed in PixInsight

I am not happy with this image.

1. It is blown out, I thought 5 minute subs would be fine, should I try 3 minute subs on this object to reduce the glow?
2. Minimal resolution of the dust lanes. Am I being optimistic shooting this with a 120mm, F7, 840 mm FL refractor. Should I give up and crank up my Edge HD 9.25?
3. I had 2 runs of 12 subs each on this object. 5 were discarded as they were affected by poor guiding. The second run was done with the object low to the horizon. Should I never shoot low to the horizon?
3. Obviously need more subs.

Thanks for looking

Atmospheric dispersion at low altitudes won’t blow your subs out , you usually end up with poor detail and fatter stars.
In any case try to image above 30degrees to minimise low level atmospheric dispersion
My best subs have always been up nice and high as you are not trying to punch through all that thick atmosphere with contains humidity (moisture) , air pollution , dust , you name it ( worse near Cities or built up areas )
My 2 cents ......
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