When I’m in the field taking images, I’m able to set the temperature of my Atik 428ex mono CCD to -10 C through SGPro. But when I bring the camera home and try to take darks, for some reason SGPro can’t cool down the camera to that temperature. It will cool it down to something between -5 and -7 C. Curiously, when I use Atik’s native camera control software, Artemis, it can set the camera to -10 C regardless of location, as you’d expect with a camera with setpoint cooling.
Utilizing different power supplies doesn’t help.
Any clues as to why SGPro can’t set the temp on my camera to the desired level when it’s not in the field?
I’m guessing that it’s cooler outside at night than it is in your home when trying to take darks. So the TEC is not able to get all the way down to -10 when indoors. Does the Atik driver give you what percentage the TEC power is at? If the TEC is at 100% power and stays around -5C that’s all the lower it goes. One bit of advice, conventional wisdom is not to power the TEC at greater than 80% power for a long time.
I’ve own a 460EX and the cooler can only go down to -27Dt, by the way the driver shows the power percentage. I’ve never had an issue related to cooling with SGP and the 460EX
I have never used the artemis software, but my guess is that the software only sets the target temp and the camera takes care of the rest.
Take a look to the logs (SGP/ASCOM), in the logs it would be easy to see if the target temp was properly set.
Cheers,
Jose
Hi guys, thank you very much for your quick replies.
@joelshort - It is indeed warmer in my home than in the field, but I thought with setpoint cooling, ambient temperature didn’t matter (at least to a certain extent). It’s about 74 F in my home. This same temperature would not be uncommon in the field during the summer months. I suppose I need to curb my expectations what the camera’s cooler is capable of.
Would you know if there’s much difference between -5C and -10C with respect to noise? If not, perhaps I’ll just shoot at -5C.
@jmtanous - The driver shows the power percentage at 100% and it does not get above -7C in my home. Also, I was wrong about Artemis being able to set the temp to -10C. The setting was actually 10C. I set it to -10C and it’s only able to achieve the same as what SGPro reports.
I checked the logs and they’re a bit misleading. They report:
[4/18/2015 1:12:40 PM] [DEBUG] [TEC Thread] TEC Change: Changing temp from 20.00 to -10.00 in 300 seconds…
[4/18/2015 1:17:40 PM] [DEBUG] [TEC Thread] TEC Change: Complete…
As an aside, I get this weird pop-up window when I use either SGPro or Artemis: “Atik Driver Server - This is an ASCOM driver, not a program for you to use.” Any idea what causes this pop-up? SGPro seems to lock up when I get this pop-up. I’m using the latest Atik drivers, dated January, 2015.
I used to have Atik 460EX which I think shares the same body as your camera and it didn’t have deep cooling probably due to pretty small camera body and I think TEC is only single stage cooling instead of dual stage like other bigger body CCD cameras.
If it says 100%, then it’s not going to get any cooler.
Peter
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The ambient temperature does matter a lot. The camera specs say it can only cool to a delta of about -25C, so if your home is 24C then you’ll only be able to get to at most -5C. Again, it’s best not to run your cooler at 100% power for a very long time.
With the Sony sensor in the camera deep cooling isn’t as necessary as other Kodak based cameras. You probably won’t see too much of a difference at 0C vs. -10C.
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