|
Hi Steve,
I have had similar issues. There are two Basic models of the QHY8, one from a mob in the USA is a sealed system, but the normal run of the mill QHY8 is not a sealed system. So air can get in through the joints and plug holes. If it is moist air then that spells trouble.
Most users tend to store the camera in a plastic ziplock bag with dessicant packs when it is not in use. This makes sure the air in the camera is dry. Simply take the camera out of the bag when you are ready to use it and then put it back in at the end of the evening. This also removes any moitsture that may have accumulated in there and prolongs the life of the camera.
Rule number one with that camera is never ever take the filter (or front glass) off when you are out in the field. This lets damp air in and will ruin the evening instantly if the camera is cold.
The coolers on these things are amazingly good and thats part of the problem. There is setup in there called a cold finger that gets cold first and is supposed to hold the ice that may form before it can get to the CCD or the filter. The problem is, that it gets so cold in there so quick everything can ice up before it can collect on the finger.
If you store the camera in a sealed bag with dessicant packs this reduces the problem alot (there is also a small rubber plug on the side that you can remove while its in the bag to let the crystals do their magic more efficiently). Just remember to fit it back in before you take the camera out of the bag :-) .
Also I use a different controller for mine. The standard controller is the DC-101. I bought a DC-102 separately (about 100 bux au). Its for their thermostatically controlled QHY9, but is pin compatible with the QHY8. As the QHY8 does not have a thermostat it still cant thermostatically control the camera, but it does let you manually control the current to the cooling system. When I setup for the night, I set it to barely cooling at all initially for the first 10 mins or so while focussing and setting up, etc. Then increase the cooling power to 50% or so if required depending on the temp outside. Since doing this I have not had iceing issues and still have beautiful clean darks and no background noise.
I hope this helps
Regards
Bill D
|