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Old 08-01-2021, 05:27 PM
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rustigsmed (Russell)
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Join Date: Mar 2012
Location: Mornington Peninsula, Australia
Posts: 3,952
Star shape assistance please - refractor :) - asi6200mm

Hi all,

I took the plunge and picked up a zwo asi6200mm to pair with my TS130mm apo. I have a .79 reducer/corrector on the scope. While I have had the scope for a while i haven't really used it much - so in reality i'm a fair refractor noob, coming across from newts.

I took a lot of LRGB last night of the horsehead, today i realised that my flats were too saturated - i didn't realise just how much the full-well reduced going from gain 0 to gain 100 (logarithmic). hopefully i can correct that tonight with duller flats (and shooting with gain 0). One issue sorted.

Anyway - I have a lot of strange shaped stars especially in the bottom left, bottom and bottom right.

Am i looking at;
- tilt /
corrector spacing /
OAG prism intrusion
/ all of the above - something else?

The spacing "should" have been correct - my corrector is screwed directly to the scope draw tube, and the imaging system screw straight onto the corrector, no clamping. I was fairly annoyed with zwo, as i purchased it based on their "telescope side M48 solution" unfortunately their M54-M48 0mm adapter is loose, there is no stop and not really a real solution at all. So I am going to have to find another connection option to increase rigidity.

Apart from that - camera seems quite good - files are about 119mb. I am very out of practice on processing, setting up etc which doesn't help

7x2mins Carina neb Ha - see star shapes lower left, lower right etc.
https://www.flickr.com/photos/803366...blic/lightbox/

attached a super quick 20minute nb starless carina for no particular reason.

cheers

russ
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