APT Tool and CCD Warming... ?

[Nikolas74]

I always have this problem when i want to warm up my CCD (ATIK 383L+) and previously with other Atik cameras, although the outside temp is at 30°C the warm up can't reach that temp... for example today it stopped at 17°C and didn't want to go to 28°C that i had set it.....

Anyone knows why ? and is it safe not to warm up the CCD at correct temp ?

Nikolas. 

[barkis]

The warm up is actually a cooling down is it not ? 
The sensor is more sensitive to faint light when cold. That set point you decide for yourself.
Usually around -20c -30c. 

Someone with more experience will come in here and be more specific.
Ron.

[tooth_dr]

14 minutes ago, Nikolas74 said:

I always have this problem when i want to warm up my CCD (ATIK 383L+) and previously with other Atik cameras, although the outside temp is at 30°C the warm up can't reach that temp... for example today it stopped at 17°C and didn't want to go to 28°C that i had set it.....

Anyone knows why ? and is it safe not to warm up the CCD at correct temp ?

Nikolas. 

I have this same Atik camera, and also use APT.  I always use warm up, but I do not use it to go to ambient temp.  I set mine to got to 5deg C so that is above freezing point and then shut it down.  I dont know why yours isnt going to 28oC.  I have never seen 28degC at my location lol.  I wouldnt be concerned, 17degC is fine.

[tooth_dr]

7 minutes ago, barkis said:

The warm up is actually a cooling down is it not ?

There is a warm up function that warms up the sensor when you are finished image to prevent dew on the sensor.

A cool down function cools it to the working temperature eg -15 or -20 degC

[Nikolas74]

Thank you for your answers, 

In my understanding the warm up procedure should reach the ambient temperature.....i am correct ??

Because this is what i can't reach......

[davew]

On the CCD cameras I've used there was no chip heater. Some cameras have a cover glass heater to prevent misting. The temperature rise on warm up was due to the Peltier voltage being ramped down in a slow and controlled way. I used Maxim and if you had nothing better to do at the end of the night, you could watch the cooler close down in the power output box

Dave.

 

 

[Robny]

14 hours ago, davew said:

On the CCD cameras I've used there was no chip heater. Some cameras have a cover glass heater to prevent misting. The temperature rise on warm up was due to the Peltier voltage being ramped down in a slow and controlled way. I used Maxim and if you had nothing better to do at the end of the night, you could watch the cooler close down in the power output box

Dave.

 

 

As Dave said above.

Its my understanding that APT will just slowly reduce power to the cooler, until the cooler is basically off.  At which point, unless your camera has an heater, you're at the mercy of the ambient temperature to continue warming the camera...you may be waiting a while.

I normally warm mine after an imaging run, once it gets well into positive figures then I just shut it down and pack up, at which point the risk of thermal shock is no longer apparent (I hope)

Rob

[Datalord]

I do the same. As long as you get to positive temperatures, you should be good. Your aim is to prevent the glass from cracking by going from -30 to +10 too fast. As long as the temperature difference is not too big, you should be fine.

[fwm891]

As long as you take the camera to a few degrees above 0°C the camera it's self will then slowly warm to ambient temp. I set mine at +5°C and allow the camera to continue warming to ambient in it's own time.

[Nikolas74]

Thank you all for your answers !!!