Cooling issue on an ASI2600MC Pro

[StuartT]

I have been making a darks library at -15C and find that during the longer exposures (180sec) the sensor starts to heat up and the cooler (working at 100%) is not able to hold the temperature.  So I have to insert a long pause between each exposure to enable the cooler to get the sensor back down to -15C which makes the whole process very long!

Has anyone else noticed this problem?

[tomato]

I don’t own a ZWO ASI 2600MC but I do have the QHY and Risingcam versions. The only problem I have with maintaining the temperature while I create a darks library is if I attempt this inside the closed dome during a warm day when the internal temp is 25 degrees C or higher. The cooler capacity moves to 100% over the course of a few subs and then the set pt temp is no longer maintained. 
 

There is no problem however if the ambient temp is < 15 deg C and there is adequate ventilation around the camera.

[Budgie1]

How much is the sensor temperature varying by?

[scotty38]

I just checked my last but one darks library on my 294mc shot at -10 and it only had two temps recorded;  -10 and -9.40. This was for 30 frames at each duration ranging from 30 seconds to 360 seconds at 30 second intervals. I did that lot non stop and it took quite some time, obviously a smaller sensor but that's a big difference compared to what you're seeing on your 2600.....

Edited May 7, 2022 by scotty38

[symmetal]

I use a desk fan blowing though the camera vent slots if I'm taking darks indoors and struggle to reach the temperature. This gives me about 10 degrees more cooling capacity.

Alan

[StuartT]

10 hours ago, Budgie1 said:

How much is the sensor temperature varying by?

about 3 or 4 degrees

What I've done now is to sit the camera on top of a freezer pack and it seems to be helping

[Budgie1]

3 hours ago, StuartT said:

about 3 or 4 degrees

What I've done now is to sit the camera on top of a freezer pack and it seems to be helping

That's a bit more than I was expecting.

Like @scotty38, I have the ASI294MC Pro and that does vary from -10° to -9° when shooting darks in the house, and I don't tend to worry about the 1° change. Looking at my darks library when I shot at -15°, there was no variation between the Dark Subs. But 3-4° is a bit more of a variation, so if the freezer pack is helping then that may be the way to go.

If the power & USB cables are long enough, what about putting it in the fridge to shoot the longer frames?

[iantaylor2uk]

Usually the dark current graphs use a logarithmic axis on the vertical scale. With my ASI 071 I only ever go down to -5C as I'm not convinced there is a big enough benefit to going even lower.

[barbulo]

3 hours ago, Budgie1 said:

what about putting it in the fridge to shoot the longer frames?

That's how I made it.

[StuartT]

19 hours ago, iantaylor2uk said:

Usually the dark current graphs use a logarithmic axis on the vertical scale. With my ASI 071 I only ever go down to -5C as I'm not convinced there is a big enough benefit to going even lower.

this is a good point. Maybe -15 is overkill. Thanks

[scotty38]

55 minutes ago, StuartT said:

this is a good point. Maybe -15 is overkill. Thanks

Yep that's why i had to go to my last but one library for -10 as I have moved to -5 too.....

[The Admiral]

Have a look at Robin Glover's video from about 21 minutes in. There's no point in pushing the temperature very low.

Ian

 

[Ouroboros]

It was that video that led me to operate my ASI2600 at -10°.

Also my ASI2600 cuts out if I try to cool it to -15 during normal daytime temperatures. I assumed it was a cutout protection. What happens if I try and cool from typical  room temperature to -15° is that the cooling switches itself off and the camera comes back up to ambient. Have others noticed this? 

[StuartT]

6 hours ago, The Admiral said:

Have a look at Robin Glover's video from about 21 minutes in. There's no point in pushing the temperature very low.

Ian

 

Thanks. That's a great video, but I think I watched it before I had enough experience to fully appreciate it. I'll watch it again.

This is the bit you're referring to. There's clearly a law of diminishing returns as you go cooler

Edited May 9, 2022 by StuartT

[The Admiral]

6 minutes ago, StuartT said:

Thanks. That's a great video, but I think I watched it before I had enough experience to fully appreciate it. I'll watch it again.

This is the bit you're referring to. There's clearly a law of diminishing returns as you go cooler

Well, more the slide that compares the thermal noise with the noise from sky background, where it can be seen that the contribution from the camera is small in comparison even at moderate temperatures.

Ian

[teoria_del_big_bang]

I too struggled some days to get -15 C indoors with my QHY268M but I find -10 C seems to be sufficient with this sensor.

Steve

[Adam J]

19 hours ago, Ouroboros said:

It was that video that led me to operate my ASI2600 at -10°.

Also my ASI2600 cuts out if I try to cool it to -15 during normal daytime temperatures. I assumed it was a cutout protection. What happens if I try and cool from typical  room temperature to -15° is that the cooling switches itself off and the camera comes back up to ambient. Have others noticed this? 

That behaviour suggests that the voltage is dropping as the cooler uses more current and causes the camera to trip out. 

Maybe take a look at the input voltage when running the camera at max cooling. 

Adam

[Ouroboros]

16 minutes ago, Adam J said:

That behaviour suggests that the voltage is dropping as the cooler uses more current and causes the camera to trip out. 

Maybe take a look at the input voltage when running the camera at max cooling. 

Adam

Yes, good suggestion.

I’m running my ASI2600 from my ASIair.  I had wondered whether the ASA could be tripping the voltage it supplies because the camera is drawing too much current. 

As I say, it’s not a problem as long as I cool the camera from typical nighttime temperatures. I’ve had to build my Darks library outside at night. 

[Zummerzet_Leveller]

I run my 2600MC at -10c and take my darks library with the camera in the fridge.  I pop it in a ventilated cardboard box and let them run.  I have found it reduces the load on the fan and haven't had an issue so far.