QHYCCD QHY8L - Manual (Page 5)

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Infrared cut-off glass window moisture
If the cooling temperature is too low in a high humidity environment, the infrared cut-
off glass window may collect dew. This is due to the temperature of the window being
too low. Please use the following method if you encounter this problem.
• Install M42 to M42 heater which produced by the QHYCCD. The heater can raise
the glass window's temperature to avoid dew forming.
• Reduce the cooling power, the best temperature range for the QHY8L is from -
5°C to -15°C. Please adjust the cooling temperature according to the ambient
temperature.
• Do not put the glass window upside down, as the cold air may collect on
the glass window
Note: You should shut off all power after you finish using your camera. If the camera
is still on, any ice crystals around CCD chip will melt which can corrupt or short-circuit
the PCB board.
9. Notes about Long term use camera and Remote Observatory
If you have to keep the camera working for a long time or the camera is working in a
remote observatory, please follow the following procedures, and we recommend that
you consult your area dealer for more details.
• Before using the camera, always check that the CCD chamber is sealed and dry.
If there are many ice crystals around the chip-this indicates high relative
humidity in the CCD chamber. You must dry the CCD chamber.
• Check the air tightness of CCD sealed chamber. You can check this by
increasing the internal pressure of the CCD sealed chamber with a hand pump
(do not exceed 1. 01MP). Then watch if the pressure drops. If the pressure
drops quickly, this indicates a lack of air tightness. You need to check if the
front cover is screwed on well.
• Put effective desiccant in the dry tube and connect continually with CCD for a
long term drying.
• Don’t supply power to the CCD for several days or even weeks if possible. Use a
power controller to control 12V input or AC input.
10. Protection of Cooler
The double cooler of the QHY8L can reach to 33-35 C difference in environmental
temperature. So it is necessary to avoid thermal shock to the cooler. Thermal shock
means internal stress of cooler changes due to expansion or contraction caused by the
rapid changes in the temperature of the cooler. Strong thermal shock will shorten the
life of the cooler or even cause irreparable cooler damage.
This is the method of avoiding thermal shock: to avoid reaching maximum cooler power
when booting camera, take care to gradually increase power of cooler. When stopping