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Old 10-06-2016, 10:07 AM
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rustigsmed (Russell)
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Location: Mornington Peninsula, Australia
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Originally Posted by Atmos View Post
At Gain 300ish 30-60s exposures are theoretically workable.
thanks Colin

Originally Posted by glend View Post
Russell i think yes short narrowband is achievable with the 1600. I have started going through all the files, basically running DSS to get scores and then checking samples. I have deleted about 50%, and processed them for the three layers. Whether 30 seconds is ideal , i don't know where the floor is, as the shorter the sub the lower the data threshold. I need to stretch to get the data to show, and 60" seems workable so far. Thankfully i did not have to shoot 30" narrowband last night, but i may test it in the future.
One thing i am finding is that Dark Calibration in DSS seems to be costing me narrow band signal data in myb6p" subs. I have compared output files of Ha and Oiii stacks with and without darks and the resulting image is much better without darks. It maybe just DSS, i fon't know how other stackers would handle it. Unfortunately i can't find a way to control DSS dark calibration thresholds. I have played around with the available dark options but so far i can't solve the problem.
However, this camera iscso low noise and smooth, that i think that imaging without darks at thise low sub times is feasible. Just have a look at Ray's M83 image, which has no dark calibration.
I will post up my NGC 6188 with out dark calibration, later today.

I should add that 30-60" LRGB subs would deliver a high signal level than narrowband obviously, and so those sub times are easily achievable imho.

Colin i am using Unity Gain settings ( Gain = 139, Offset = 21) on my 60" narrowband subs and they seem to be ok.
thanks Glen, I'm interest in shorter subs as I'm thinking of using on a goto dob. I guess even binning 2x2 is an option considering the megapixels.

I wouldn't worry too much about using darks. I haven't used them for ages and if they are causing grief for now give it a shot without them
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