Re: To Gain or not to overGain
Posted: Mon Oct 15, 2018 7:55 pm
Hey Guys , now that we have covered the section on OSC hypercam gain/ exposures...
we have a new set of issues to work out.!
NB_SHO imaging AA183MM
i ran the Brain 2 nights ago and it reported = failed to find any exposure in 300 sec using the Ha filters Gain at 400 to start and 40 offset.
the image was black under SQM = 20.08 ,
So now we need to address the NB SHO problems with the Hypercams 183MM .
sos we are right back where we started , in a way with :
1-HIgh Gain ( 500~1200) / short expos ( under 60 Sec)
2-then low gain (400 and under) and 300s ~ 600 sec subs to just reach 100 ADU on the histo gram. and a huge Star burst to boot ....( and amp glow)
All my friends with ASI 1600 MM shoot at Unity gain 139 (of 600) and offset 21 / with 300 sec subs and get an ADU of 1250 ish . at 16 bit.
now i understand that the ASI is only 56% QE and the AA183MM is 84% , but that should help it now make it worse...
SO now for some test the AA183MM to see how long of an exposure we need to reach ADU 100 so that DSS4.1 and Pixinsight 1.8 doesnt cry a river with
( NO STAR FOUND ) empty image ...
So back to the drawing board on the over gain under exposures, to get the right dynamic range and be able to stack the subs....
3- if using 300 sec subs to get a target you will find yourself short on subs for noise reduction on the hypercam ( i usually shoot 200-600 subs at 30 sec )
but now in a NB SHO environment this wont work... or i will only get 20 -30 subs on each channel and this will make problem with noise reductions.
IF the star burst was not a problem then i would shoot LOW gain and long subs to get my ADU to 100 or over ( higher) for stacking reasons.
will keep testing and waiting on any of you guys remarks , and also on Robins take on this ....
so far all testing has been done with SGP and that is a problem SDK DRiver wise...
we have a new set of issues to work out.!
NB_SHO imaging AA183MM
i ran the Brain 2 nights ago and it reported = failed to find any exposure in 300 sec using the Ha filters Gain at 400 to start and 40 offset.
the image was black under SQM = 20.08 ,
So now we need to address the NB SHO problems with the Hypercams 183MM .
sos we are right back where we started , in a way with :
1-HIgh Gain ( 500~1200) / short expos ( under 60 Sec)
2-then low gain (400 and under) and 300s ~ 600 sec subs to just reach 100 ADU on the histo gram. and a huge Star burst to boot ....( and amp glow)
All my friends with ASI 1600 MM shoot at Unity gain 139 (of 600) and offset 21 / with 300 sec subs and get an ADU of 1250 ish . at 16 bit.
now i understand that the ASI is only 56% QE and the AA183MM is 84% , but that should help it now make it worse...
SO now for some test the AA183MM to see how long of an exposure we need to reach ADU 100 so that DSS4.1 and Pixinsight 1.8 doesnt cry a river with
( NO STAR FOUND ) empty image ...
So back to the drawing board on the over gain under exposures, to get the right dynamic range and be able to stack the subs....
3- if using 300 sec subs to get a target you will find yourself short on subs for noise reduction on the hypercam ( i usually shoot 200-600 subs at 30 sec )
but now in a NB SHO environment this wont work... or i will only get 20 -30 subs on each channel and this will make problem with noise reductions.
IF the star burst was not a problem then i would shoot LOW gain and long subs to get my ADU to 100 or over ( higher) for stacking reasons.
will keep testing and waiting on any of you guys remarks , and also on Robins take on this ....
so far all testing has been done with SGP and that is a problem SDK DRiver wise...