Another tread for help with the 1600mm gain and exposure setings

[benklerk]

Hi all

I'm trying to find the best settings to make use of my setup and time imaging, and some of the advice I have read isn't really helping me.

I have a GSO 6" RC f/9 and LRGB ZWO filters with Astronomik HA and OIII 6nm filters. I also have a belt mod on my HEQ5 Pro and on a good night I can track for 20min, but would like to keep it under 15min.

I live in 21.3 skies which is at the bottom end of bortal 4 almost bortal 3 skies.

From the past few nights I have been trying different settings. On the same target.
At Gain 0 the ADU should be around 420
For L 4min exposure I got is 430 ADU and 5 min is 450 ADU.

But at Gain 75 the ADU should be 340.
For L 5 min exposure is 350 ADU

Why do I need a longer exposure at a higher gain?
Even my RGB ADU at both gain settings need over 5min to reach the desired ADU settings.
Even my NB filters showed no improvement for ADU at 15min exposure.

Do I change it to unity settings as I cannot put on a focal reducer on my scope.

I'm using this to compare my data with, http://www.iceinspace.com.au/forum/s...d.php?t=155908
http://www.iceinspace.com.au/forum/s...d.php?t=167167

Any help would be great. I just want to find the best settings for my setup without losing the quality in the images.

[Marke (Mark)]

I have a RC10 and asi1600 and 102apo and tried various things imaging from suburban Sydney . I have settled on unity gain 60s RGB 30-60s L and NB all 300s this works very well I find just dont stress to much about it try a few settings and settle on what works for you and stack a lot more images .

[glend (Glen)]

Try using the Unity setting (Gain 139, Offset 20), and as the previous post suggested, short subs might be best, but a lot of them. For NB, the 1600 works well at Unity and 300 sec subs. Have you consulted Ray's exposure charts? I find them very accurate. Unfortunately, shooting at f9 your giving away a lot of time.

[Stonius (Markus)]

We need to stick those files in the resources section.

Markus

[ZeroID (Brent)]

Originally Posted by Marke

I have a RC10 and asi1600 and 102apo and tried various things imaging from suburban Sydney . I have settled on unity gain 60s RGB 30-60s L and NB all 300s this works very well I find just dont stress to much about it try a few settings and settle on what works for you and stack a lot more images .

Marke, what is the f # of your scope ?
I'm using a Lunt 102 ED @ F7 and similar numbers under similar ( suburban skies ) conditions.

[Marke (Mark)]

Originally Posted by ZeroID

Marke, what is the f # of your scope ?
I'm using a Lunt 102 ED @ F7 and similar numbers under similar ( suburban skies ) conditions.

I am using a 102 f/7 and the RC10 at f/8 and f/5

[ZeroID (Brent)]

OK, thanks Marke, good comparable numbers then. I'll stick with the plan.
I have other scopes at 10F5, 8F6, 8F8 to experiment with. All Newts.