Parameters for the ASI2600MC Pro ZWO ASI2600MC Pro · Daniel Arenas · 8/10/2022 · 58 · 5015 · 19

Hi everyone,

It seems to be that I'm the first one who create a forum of our camera using the new implementation of Astrobin forums of equipment.

Basically, there are two important questions about how to configure the parameters of this camera. One is the gain and the other the offset (of course we can talk about the temperature also).

About the gain:

We discussed it in a thread that I opened some months ago. Here it is: https://www.astrobin.com/forum/c/astrophotography/deep-sky/choosing-gain-for-asi2600mc/
In that case, the majority sets to gain 100. I've tried it and seems to be ok for me.

The other paremeter I want to ask you is the offset you use with gain 100 in the ASI2600MC Pro. I've read that this parameter is about not to clip the histogram and to separate it from the left axis a bit.

I use NINA and in this program I've set the camera configuration in Offset 1 but because is the minimum. Let me show you:



To know how is the histogram, I've used the ASIFitsViewer program with a light in order to see it:





It seems not to be clipped. Maybe I can let the Offset in 1?


Ah! About the temperature...

I try to use a standard for me, the -10ºC but just for convenience. I don't want the camera work at 100%, and -10ºC let me in 60 - 70%. Of course in winter I can try -20ºC but in summer (now we are at 28ºC at night) its a bit complicated.

Please, let me know your parameters.

Clear skies to everyone!

Daniel

Werny Michael:
hello, I only use it at gain 100 with good results. It's the same for temperature. -5 at the hottest and -20 when winter is here. 

Clear Sky

Hi, @Werny Michael,

No offset parameter set in any place?

I always use gain 100 offset 18 (find through sharpcap analysis) and temperature of -10, I never change anything for laziness and because it works good

Thanks for creating this. I live in Texas where the temperature can be 105 degrees F or hotter when the sun is up and often the temps stays in the 90s so for me, getting the cooling to -10 requires the camera to work very hard and so I go to 0 degrees so that it isn’t working as hard.

I always use gain 101 to make absolutely sure that I'm working above the noise drop off listed in the product literature. Cuiv does the same thing but he does state that 100 is probably OK. 101 is belt and suspenders and I figure 1 point is not making an big impact on filling up wells.


I also always use offset 50 but I cannot remember where I got this setting from. It may have been from Dr. Robin Glover's (Sharp Cap Author) lecture that I find very informative and have watched many times. https://youtu.be/3RH93UvP358
The idea, I understand, is to make sure that the value is above the value recorded from shot noise by any well.

Michael Southam:
I always use gain 101 to make absolutely sure that I'm working above the noise drop off listed in the product literature. Cuiv does the same thing but he does state that 100 is probably OK. 101 is belt and suspenders and I figure 1 point is not making an big impact on filling up wells.


I also always use offset 50 but I cannot remember where I got this setting from. It may have been from Dr. Robin Glover's (Sharp Cap Author) lecture that I find very informative and have watched many times. https://youtu.be/3RH93UvP358
The idea, I understand, is to make sure that the value is above the value recorded from shot noise by any well.

But look at the first graph, which is logarythmic! With gain 0 you have 50k full well, with gain 100 you have appr. 15k. In my opionion one of the nicest features of this cam is the high fw capacity and we are cutting it, when we shoot always at gain 100...

Daniel,
Like Stephan, I live in Texas and set mine at 0 degrees with our heat.  I have always used 100 gain and I think that is the max that the ASIAir will let me set, but 100 is what I read from ZWO is the optimal setting for this camera.  Jim

Mathias Böhme:
Hi, 
in my opinion, Gain depends on the target, filters and guiding stability. It's always a tradeoff between dynamic range and noise.
With higher gain you are lossing DR.
If i have a target with a wide dynamic range or a target where i want to highlight the natural colours (cluster or galaxy) i use Gain 0. 
On the other  hand i use Gain 100 when i'm shooting nebulas, espacially with DNB Filter to reach background limitation.

The temparture is 0 degree in summer and -10 in winter - but if you are background limited this doesn't make a big difference at all.
As an AAP user the Offset is set automatically. I believe AAP sets it to 50 every time.
I can highly recommend these videos on the whole topic. It opens your eyes in understanding the physics of a camerasensor ;-)
https://youtu.be/3RH93UvP358
https://youtu.be/ub1HjvlCJ5Y

CS
Mathias

You make some good points Mathias in your post and your reply to mine. I like the idea of lowering the gain to 0 when imaging bright objects like planets/clusters. I pretty much specialize on imaging nebula and havn't had any issue with blown out areas that would come from full wells (except M42 core obviously). Fighting noise is a much bigger problem for me which I think would be compounded with the more than double read noise seen with low gain values. As you say 'depends on the target'

I'm only about 6 months into owning this camera and much of that we spent with cloudy skies and no imaging to get familiar with it. So my opinions here are just opinions and can be taken with a grain of salt.

Unlike some of the others here, I tend to keep my settings the same regardless of conditions. That being said, I haven't really experimented in the really cold time of year with the understanding, at least a rudimentary one, of what offset (or any other varibe for that matter) actually means. That doesn't mean it won't change at some point, that's just what I'm doing right now. I'm using exposure time as my exclusive adjustment. Right now I'm doing 100 gain, 25 offset, and -5° C. And always, always always dew heater on. Because of a lack of understanding, I wasn't using offset at all until about 6 weeks ago. Haven't decided if it's made any difference or not. My post processing is still pretty basic to bad, so what I'm getting out of it I have not been able to determine. But 25 seemed to be the most frequently advised number. As far as temperature, it seems like the main goal is to just prevent it from heating up during a long exposure, so I really have no intention of running that any cooler during the colder time of year. Unless somebody has some definitive research that indicates that running at any cooler (within device capabilities) is going to improve the image. Now I'm sure if one could cool that thing down to say 5 to 10 Kelvin it would probably make quite a bit of difference. But I have my doubts that -5 to -10°C is going to be any major difference. I have a tendency to over correct in many aspects of life, so I am trying to use this hobby as an exercise in patience and conservative management with subtle adjustments. So keeping as much consistency as possible from session to session is my goal in this process.

Michael Southam:

Mathias Böhme:
Hi, 
in my opinion, Gain depends on the target, filters and guiding stability. It's always a tradeoff between dynamic range and noise.
With higher gain you are lossing DR.
If i have a target with a wide dynamic range or a target where i want to highlight the natural colours (cluster or galaxy) i use Gain 0. 
On the other  hand i use Gain 100 when i'm shooting nebulas, espacially with DNB Filter to reach background limitation.

The temparture is 0 degree in summer and -10 in winter - but if you are background limited this doesn't make a big difference at all.
As an AAP user the Offset is set automatically. I believe AAP sets it to 50 every time.
I can highly recommend these videos on the whole topic. It opens your eyes in understanding the physics of a camerasensor ;-)
https://youtu.be/3RH93UvP358
https://youtu.be/ub1HjvlCJ5Y

CS
Mathias

You make some good points Mathias in your post and your reply to mine. I like the idea of lowering the gain to 0 when imaging bright objects like planets/clusters. I pretty much specialize on imaging nebula and havn't had any issue with blown out areas that would come from full wells (except M42 core obviously). Fighting noise is a much bigger problem for me which I think would be compounded with the more than double read noise seen with low gain values. As you say 'depends on the target'

I think the besr way to fight the noise is to achieve a high amount of total exposure time. 
We are not talking about lucky imaging… I think people often are trying too hard to push the SNR of the subs but tend to forget that with stacking many background limited frames the noise doesn’t get problem at all.

Zwo recommends gain 0 / offset 30 or gain 100 / offset 50.

Hi Mesli,

So, ZWO has pronounced about that issue? May you tell me where to read it, please? I have not found it.

Many thanks!

I agree with @Mesli and @James R Potts above, and I can testify further that I too have read ZWO's recommendations but I unfortunately  don't remember the source.  I have used the 2600MC for hundreds of images using SharpCap and ASIAIR and have learned a few things I can report with certainty, although I have no experience with the 2600MM.
With SharpCap sky analyzer, for those unfamiliar, the app reads the FOV and recommends gain and exposure settings based on a  sensor analysis for any given camera provided you do the sensor analysis before hand.  In all my experience SharpCap never recommended an offset greater than 20 or a gain setting greater than 121 with My 2600MC or my 294MC but SharpCap is based on more of a lucky imaging protocol I think.


The other, more important item to note is that ZWO ASIAIR offers NO OFFSET CONTROL of the 2600MC or 533 and 294 for that matter.
A quick FITS header read in Pixinsight shows that the ZWO factory setting -which the user cannot change in the 2600MC-  is   50   .

The fact that ZWO does not want the user to be able to change offsett seems to support the idea that the cameras are designed with what might be called "sweet spots" or certain settings at which maximum performance is attained.  The gain, DR, RN, etc. graphs already presented above would support this also.


So Daniel, I would say ZWO highly recommends an offset for your camera of 50 and Gain settings of,   0 for bright objects, 100 for most objects and from my experience I can tell you that use of a filter requires a gain of al least 100 and often much much higher.
Also set your sensor cooling to -10 and leave it there year round.

I hope this helps.
scott

Just to add one point to this discussion. In setting offset you want to set it so that you are not clipping your DARKS, not your lights. If you clip your darks then you will not properly subtract the noise from your lights. ZWO uses offset 50 (which actually gives you 500 adu offset) with gain 100. For higher gain you must increase the offset--for example I use  offset 150 (gives 1500 adu offset) for 350 gain, which doesn't substantially clip my darks. Note in setting the offset on your dark there may possibly be dead pixels that register zero no matter what, so don't kill yourself with huge offsets to try to get rid of 0.2% dark pixels.
CS
Rick