Re: [ccd-newastro] CCD TEC cooling info please
- hanks for the info people....It is a great help and I better builld that daRK LIBRARY...Clear skies...dave
Sent: Friday, November 30, 2012 6:06 PM
Subject: Re: [ccd-newastro] CCD TEC cooling info please
For amateur CCD cameras, cooling is _always_ relative to current ambient temperature. Since lower temps are always to be preferred, you will generally want to cool to (ambient - max the camera can manage).
So if it is 15C absolute (ambient), and your camera can cool -20C relative to ambient, you will be able to cool to -5C absolute. If it is -15C absolute, then you can cool the camera another -20C to -35C absolute.
The TEC cannot warm the camera; it's strictly a one-way device (cooling). And since you want the lowest possible noise in your exposures (so as not to waste your time!), you will generally use rainy and cloudy nights to build dark libraries for multiple temperatures, and use different temperature ranges in different seasons. You don't need to cover every possible temperature; you can make libraries for each 5 or 10 degrees in the range for the current season.
On Nov 30, 2012, at 9:24 AM, Dave <mailto:terrarouge%40pei.sympatico.ca> wrote:
> Hello all.I have a QHY8 Pro with TEC cooling.Now I understand that when in warmer weather I choose a TEC temperature less ambient temp...Say outside it's 15 degrees Celsius and I set TEC temp to -20 Celsius which is what I usually set it at, but what do I set temperature too when it's really cold outside say -25 Celsius.Would the TEC temperature ,if set to -20 Celsius, warm the CCD camera and cause noise,dew or be harmful in anyway,should I always set TEC cooling to lower setting than ambient temperature....OR should I just leave the TEC cooling off?Please let me know as I have really never used this camera in really cold temps and I just need to know how to set Tec temperatures for cooling in cold ambient temperatures...Clear skies...Dave
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