Camera Maintenance
The G2 CCD camera is a precision optical and mechanical instrument, so it
should be handled with care. Camera should be protected from moisture and
dust. Always cover the telescope adapter when the camera is removed from the
telescope or put the whole camera into protective plastic bag.
Desiccant exchange
The G2 CCD cooling is designed to be resistant to humidity inside the CCD
chamber. When the temperature decreases, the copper cold finger crosses
freezing point earlier than the CCD chip itself, so the water vapor inside the
CCD chamber freezes on the cold finger surface first. Although this mechanism
works very reliably in majority of cases, it has some limitations, especially
when the humidity level inside the CCD chamber is high or the chip is cooled
to very low temperatures.
This is why a cylindrical container, filled with silica-gel desiccant, is placed
inside the camera head. This cylindrical chamber is connected with the
insulated cooled CCD chamber itself.
Warning:
High level of moisture inside the CCD cold chamber can cause camera
malfunction or even damage to the CCD sensor. Even if the frost does not
create on the detector when the CCD is cooled below freezing point, the
moisture can be still present. It is necessary to keep the CCD chamber interior
dry by the regular exchange of the silica-gel desiccant. The frequency of
necessary silica-gel exchanges depends on the camera usage. If the camera is
used regularly, it is necessary to dry the CCD chamber every few months.
It is possible dry the wet silica-gel by baking it in the oven (not the microwave
one!) to dry it again. Dry the silica-gel for at last one or two hours at 120 °C.
Exceeding the 120 °C limit can damage the silica-gel and limit its ability to
absorb moisture.
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