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Re: CCD TEC cooling info please

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  • mark_manner_spot_obsrv
    What I usually do is two different standard temperatures, one for summer and one for winter. I pick a temp that is lower than ambient is likely to be, and just
    Message 1 of 4 , Nov 30, 2012
      What I usually do is two different standard temperatures, one for summer and one for winter. I pick a temp that is lower than ambient is likely to be, and just stick with it. For me with my STL cameras, I use -10C in Summer and -20C in Winter. If I were in a different climate, I would pick appropriate temps. I like to build new dark/bias master frames at least twice a year so this doesn't cause any issues.
      I hope this helps, although I know it doesn't answer the 'can the TEC warm the chip' question. I probably wouldn't use it to warm it, even if it could, but that isn't based on any testing on my part.
      Mark

      --- In ccd-newastro@yahoogroups.com, "Dave" <terrarouge@...> 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
      >
    • yahoo@wodaski.com
      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
      Message 2 of 4 , Nov 30, 2012
        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.

        Ron Wodaski



        On Nov 30, 2012, at 9:24 AM, Dave <terrarouge@...> 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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      • Dave Cunningham
        hanks for the info people....It is a great help and I better builld that daRK LIBRARY...Clear skies...dave From: yahoo@wodaski.com Sent: Friday, November 30,
        Message 3 of 4 , Nov 30, 2012
          hanks for the info people....It is a great help and I better builld that daRK LIBRARY...Clear skies...dave

          From: yahoo@...
          Sent: Friday, November 30, 2012 6:06 PM
          To: ccd-newastro@yahoogroups.com
          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.

          Ron Wodaski

          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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