Choosing gain for ASI2600MC?

CMOS Acquisition Beginner Deep Sky
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Daniel Arenas avatar
Daniel Arenas avatar
Hi,

I’ve bought an ASI2600MC but I come from a DSLR non modified so I’m doing some tests at home but I don’t have any experience on dedicated cameras. 

what I was thinking about is to set the gain to 100 and then modify the exposure time. Is this a good praxis or do you recommend any other way to do?

I’ve said gain 100 because I’ve read in forums that is the better one but I don’t know if it’s true. 

Anyone who owns the ASI2600MC can tell me?

Many thanks and clear skies!
andrea tasselli avatar
andrea tasselli avatar
Gain 100 is the way to go, maximum dynamic range with the minimum read noise.
Malcolm Loro avatar
Malcolm Loro avatar
The default settings for the ASI2600 are Gain=0, Bias=50. I use these settings and they seem fine, but I have not experimented with Gain=100. 

Here's what ZWO says on the subject:
"The ASI2600MC Pro boasts excellent performance with a dynamic range of up to 14 stops. When the gain value is set to 100, the HCG high gain mode is turned on. We’re not saying it’s magic…but we’d like to think it is pretty close. With the HCG-mode turned on, the readout noise is greatly reduced, and the dynamic range is basically unchanged. To improve the data quality, it is recommended to set the gain to 0 or gain 100 during deep-sky imaging."

I believe ZWO ASCOM driver limits the gain to 0-100, because above 100 you will have significant loss of dynamic range.
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SemiPro avatar
SemiPro avatar
andrea tasselli:
Gain 100 is the way to go, maximum dynamic range with the minimum read noise.

Yup, this is the way to do it. There is no reason to use any other setting because of the nature of the high conversion gain or whatever its called. If you need to tweak your histogram, you do it through manipulating sub exposure times, not the gain on the 2600MC.
kuechlew avatar
kuechlew avatar
It's very easy to understand: In the old database the very same equipment has been entered in very different ways, so you have multiple different entries for the same stuff. The data migration attempts at introducing a well defined description for each item in a way that each item is represented by only one dataset in the database. This can not be achieved in an automated way, so astrobin requires some support by its community. It's a bit annoying but requires only a quite small time investment. As a result it will be much easier to link images or users with the same gear. I encourage all astrobin users to support this data migration.

Clear skies
Wolfgang
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kuechlew avatar
kuechlew avatar
It's very easy to understand: In the old database the very same equipment has been entered in very different ways, so you have multiple different entries for the same stuff. The data migration attempts at introducing a well defined description for each item in a way that each item is represented by only one dataset in the database. This can not be achieved in an automated way, so astrobin requires some support by its community. It's a bit annoying but requires only a quite small time investment. As a result it will be much easier to link images or users with the same gear. I encourage all astrobin users to support this data migration.

Clear skies
Wolfgang

Sorry, wrong thread ...
Tom Boyd avatar
Tom Boyd avatar
As other's have noted, the sweet spot on the gain is 100. You can see this by looking at the graphs on page 7 of the ZWO 2600 manual:

https://astronomy-imaging-camera.com/manuals/ASI2600_Manual_EN.pdf
Rod Hughes avatar
Rod Hughes avatar
ZWO gain limits are 0 to 100 only when using their ASCOM driver. If you use ZWO ASI Studio, the gain can be adjusted well beyond 100.

Offset setting is something many CMOS camera owners understand. I think of Offset as a bias tweak so to make sure dark signal is not being clipped. For more information on Offset, watch this YouTube video: https://www.youtube.com/watch?v=_IfXzXM9XFY&t=6s.

Rod
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Arun H avatar
Arun H avatar
While gain 100 has lower read noise, gain 0 has higher full well capacity and the same dynamic range of 14 stops. That means less probability of saturating bright stars at Gain 0. The difference in read noise between gain 100 and 0 is not meaningful - 1.5 vs 3.5 electrons - and I value the greater full well capacity at gain 0 more. You can expose over twice as long at gain 0 vs 100 before you saturate the pixels. All of my images with this camera and those taken by my colleagues were done at Gain 0.
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