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#1 ValeryD

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Posted 15 July 2013 - 01:25 PM

Hi Bob,

I have a question to you. You writes at your profile "cooled PGR Chameleon".

Which one do you have, what is the cooling system, what is the working temperature for the chip? What the real benefit in image noise decreasing this cooling provide?

Thanks.

Valery.

#2 BYoesle

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Posted 16 July 2013 - 07:01 PM

Hi Valery,

I have the standard Chameleon in a plastic case. As noted by Luca it can run a bit warm, especially on hot summer days: web page The cooling system is home-made using a surplus CPU cooler & TEC, it reduces the chip temp by about 20+ degrees C. It seemed to have a significant effect in my test dark frames. You can go to this link for the thread describing the modification: CN link

NOTE: I have since abandoned focal reducers in favor of mosaics for full disk images.

I also considered replacing the Chameleon's plastic housing with a metal one, which I believe would further improve the TECs cooling ability, but I haven't got around to this -- yet...

#3 ValeryD

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Posted 17 July 2013 - 01:48 PM

Hi Valery,

I have the standard Chameleon in a plastic case. As noted by Luca it can run a bit warm, especially on hot summer days: web page The cooling system is home-made using a surplus CPU cooler & TEC, it reduces the chip temp by about 20+ degrees C. It seemed to have a significant effect in my test dark frames. You can go to this link for the thread describing the modification: CN link

NOTE: I have since abandoned focal reducers in favor of mosaics for full disk images.

I also considered replacing the Chameleon's plastic housing with a metal one, which I believe would further improve the TECs cooling ability, but I haven't got around to this -- yet...


Thanks, Bob! After you sent me the the link via PM, I have read that thread with a great interest.
The main question still not answered directly - how much improvement this cooling provides vs uncooled version.
It is difficult to believe, that at 2 - 20ms exposures will be any significant improvement in image quality. But this can be more pronounced when imaging the sun at longer exposures with 0.5A and especially for fainter prominences with such narrow band pass.

I still wait for surprise from one or two manufacturers, who will introduce very sensitive, high speed and at the same time larger format and VERY LOW read noise.

The EM CCD cost too high now.

#4 Footbag

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Posted 17 July 2013 - 02:32 PM

Interesting! I've noticed as recently as yesterday that the Chameleon doesn't like it when it gets to hot out.

According to Firecapture, it was 137F and only giving me 5 FPS. I keep saying to myself, this thing need cooling.






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