Gain/Offset with ASIAIR Pro and ASI533MC (or any ZWO camera)

ZWO ASI533MC Pro CMOS Acquisition Deep Sky
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DanRossi avatar
DanRossi avatar
Hi all,

I've started to use the ASIAIR Pro with the ASI533MC Pro and I've noticed there's no way to set the Offset for the camera.

I believe ZWO fixed the Offset at 50 with the ASIAIR, so two questions:

  • What are the Pros/Cons to this?[/*]
  • What are optimal Gain settings for LRGB and narrowband with this Offset in mind?[/*]
My first couple of images on the Wizard Nebula have come out with a white "haze" over them which is leading me to conclude my Gain settings were too high (200 and 125 respectively) for LRGB images.  For reference I used an 8" reflector and here are the details of each imaging session:

  • Image 1:   2 hrs, 120 sec subs, 200 Gain[/*]
  • Image 2:  1 hr 45 min, 120 sec subs, 125 Gain[/*]

Any insight would be greatly appreciated.

Thanks!
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James avatar
James avatar
For asi533, a gain of 100 is a safe spot to start.  How long your subs are will depend on how dark your skies are.
adastro_tothestars avatar
adastro_tothestars avatar
I have looked at the "ASIFITSVIEW" in the ASISTUDIO, and I noticed the offset is set at 30. 

Not sure what that means if its good or bad, but it's set at 30 on both my ASI1600MM and ASI294MC
Sean van Drogen avatar
Sean van Drogen avatar
Believe unity gain for the ASI533 is 100. So that would be a good place to start i think. ZWO fixes the offset for all their cameras to what they think is best. For my 183MM pro its set at 10. With NINA I can potentially change the offset but never found the need to do it.
This is a very good article to understand what offset is https://daleghent.com/2020/08/understanding-camera-offset
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SemiPro avatar
SemiPro avatar


So as you can see, there is no point in really moving from 100 gain. If it was me I would stick to 100 (I used 105 just to be safe) and instead of messing around with the gain, tweak your exposure times to get the histogram you want. It's not like your 264mm where you will be playing with the gain all the time. This is a kind of set it and forget it camera when it comes to that.
Dave B avatar
Dave B avatar
Zwo533mc setting of 100 gain and off set 10 for best dynamic range , if you look in the little booklet that comes with camera there are three gain setting in the zwo driver to choose from ,and all is explained , I use APT and set the gain /offset at 100 gain 10 off set , if I use with a L exreme filter I use 120 Gain 10 offset ,
Tommy Blomqvist avatar
Tommy Blomqvist avatar
I am running my 533 from ASIAIR PRO with gain 100 and offset 70.
This works well with Optolong L-pro and Astronomik L-2 filters but when I am using my L-eNhance I do raise the gain till around 120 if the object isn't very bright.

(There seems to be no easy way to change the offset in AAP (I did check this when I upgraded the software last week).
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Sathya Sharma avatar
Sathya Sharma avatar
Tommy Blomqvist:
I am running my 533 from ASIAIR PRO with gain 100 and offset 70.
This works well with Optolong L-pro and Astronomik L-2 filters but when I am using my L-eNhance I do raise the gain till around 120 if the object isn't very bright.

(There seems to be no easy way to change the offset in AAP (I did check this when I upgraded the software last week).

I have the ASIAIR MINI. How do I set the offset in it please? I am a new user for the ASIAIR.
TIA,
Sathya.
Jonathan S. avatar
Jonathan S. avatar
Sathya Sharma:
I have the ASIAIR MINI. How do I set the offset in it please? I am a new user for the ASIAIR.
TIA,
Sathya.

Offset is set automatically by the ASIAIR, it's not a setting displayed to the user. For all of the 533 sensors I've owned it has been 70.
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