Set notification for camera temp drop?

Is there a way to set up some warning or notification that the camera temperature has dropped? Having issues with my asi2600 stops cooling and says it’s 100% cooling but isn’t. Would be nice to have a alert saying the temp is not with in a certain range of what it set at. Tired of having to go through fits headers and look at sensor temps and trash frames.

I keep seeing people with this “problem”. The issue is with the ZWO ASCOM driver, and I have lobbied ZWO a few times now to fix it (or in their eyes change it because they don’t see it as a problem).

What happens is that the ZWO ASCOM driver cools the camera in two steps in order to “protect” the sensor for thermal shock.

I noticed this behavior a month or so ago. If I set the camera temp in SGP to -10C the camera will cool to 0C and climb to 100% power. After a minute or two, the camera will start to warm up but the power stays at 100%. I think this is because there is a safety thing in the driver that think “uh oh, the power is staying at 100% which isn’t good for the camera so let’s shut it off.” In my opinion this is a bug. But ZWO doesn’t think so.

Instead, if you first cool the camera to 0C and let it stabilize (the power will be less than 100%), and then set the temp to -10C (or whatever) the camera will cool properly.

I suggest you lobby ZWO about this.

Hi Joel,

don’t you use SGP’s function “Set to … °C in … m”?

For cooling down the camera, some time is needed because the heat that is generated at the ventilator side of the Peltier element has to be dissipated. Also it must be considered that the electrical current that flows through the Peltier element also produces heat which must be dissipated as well. And finally a Peltier element does not like at all being used at a cooling power of nearly 100 %. Definitely you should avoid to operate the cooling unit at > 70 % cooling power, also for short duration.

Therefore it is reasonable to cool the camera slowly (e.g. by a temperature difference of 30 K in 15 min) in order not to cause an overload of the cooling unit.

However, I don’t think that thermal shock is relevant for the cooling procedure.


Yes, I do use SGP camera control function to cool the camera. My usual settings are to cool to -10C over 5min.

But this is not just a case of trying to cool the camera too quickly or something like that. As stated above, if I set the camera to cool to -10C the camera will reach 0C and stay there while the power climbs to 100%. At that point the camera will start to warm up, and the power remains at 100% (or at least that’s what the ASCOM driver is reporting). I should also note that this behavior happens with both my ASI2600MC and ASI6200MM.

If instead I put the set point at 0C (in SGP of course), the camera will cool to 0C and the power will be around 40% (on a typical night for me). Then I set the temp to -10C and the camera cools just fine and reaches a peak power around 60%.

I have never experienced anything like this with any other camera I have owned (too many!). This is a bug/problem with the ZWO ASCOM driver only. If one uses the native camera driver in other software the camera cools properly to -10C very quickly.

When I explained all this to ZWO I was told it was expected behavior, even as they also told me to use the native driver to avoid this scenario. So they know this behavior exists but haven’t taken any steps to correct the ASCOM driver.

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I see. This is indeed strange behavior. I always used the ASCOM driver and never observed that the temperature stayed at 0 °C with my cameras (ASI294MC, ASI071MC). So it might be that this is not a driver issue but rather a camera specific issue.

With my ASI071 I also use a 2-step cooling procedure: at first cooling to 2 °C, then to the end temperature of -10 °C, albeit for some other reason (in order to avoid condensation on the sensor protective glass). This works well for me so far.


It certainly could be a camera specific issue especially considering that the ASI2600 and ASI6200 have similar sensors and were released around the same time.

It would be an interesting experiment if you would set your camera to cool in one step to -10C and see what happens.

I will do that next time with the ASI071 and report.


Hi Joel,

tonight I cooled my ASI071MC Pro in one step to -10 °C in 25 min. Ambient temperature was 17 … 16 °C. No problems, the maximum cooling power (64 %) was indicated when the target temperature was reached. Later on the cooling power slowky dropped to 59 %. Fortunately no dew condensed on the protect window.


Interesting. Thanks for the report. There must be some difference between these cameras, or a difference in the ASCOM driver. What version of the native and ASCOM driver do you have installed? I have native driver and ASCOM driver installed.

I use the following versions:

ASCOM camera driver, ASI native camera driver


FWIW as another data point, using the Ascom driver I cool my 6200MM to -5C over zero minutes in one hit and have never seen this warming behaviour. Power does reach 100% prior to reaching the -5C setpoint but once it reaches -5C it then reduces to around 60% when ambient is 29C. Perhaps you’re seeing a driver bug, but my camera arrived last month so perhaps it uses upgraded (bug free) firmware. Clearly a bug, despite what ZWO may be claiming. The next time I fire up that imaging rig I’ll confirm which drivers I am using.

This approach (cooling down as fast as possible) is not reasonable at all. The heat has to be dissipated, and that needs some time, because the max heat flow flow is limited. I guess there is no risk of thermal shock for the sensor, but the peltier element would honor if you would allow to cool more slowly - in terms of aging and working life of the peltier element.


Looks like I am using:
ZWO Ascom driver

Maybe you Ascom driver is a little old Joel?

I’ll update the drivers and see how it goes. I wonder though if this is really a camera firmware issue.