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Old 25-06-2019, 02:19 PM
Imme (Jon)
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Imme is offline
Join Date: Aug 2017
Location: Kyneton
Posts: 839
An old thread back to life I know......however this seems to be the 'goto' advice on the web.

Just moving in to NB and have done a few tests the last couple nights however my stars are being blown out significantly using far less than recommended exposure times.

As I said, new to NB, so a question - should I expect the vast majority of stars reading at 65K+adu when reviewing subs on SGP?

Using the table I ascertained I needed a 30'ish minute sub using an F6.7 with the asi1600 set to 200 gain/50 offset. (Sky is easily in the 21+ mag range and picture taken pre moon rise). To be honest 30 minutes scared me so I went 10 as a trial.......the result, about half my stars were saturated and I had a background ADU around 3000 (bias subtracted - value 180)

I cant think what a 30 minute sub would end up like!

I'm thinking tonight I will work out exposure times based purely on background ADU rather. If I recall correctly I did similar with the ASI1600 OSC I used and those pics came up well.
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