Camera Maintenance
The G3 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 G3 camera 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 attached to the insulated
cooled CCD chamber itself.
Warning:
High level of moisture in the CCD chip chamber can cause camera malfunction
or even damage to the CCD chip. 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. 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
temperature between 120 and 140 °C.
The silica-gel used in G3 cameras changes its color according to amount of
water absorbed – it is bright yellow or orange when it is dry and turns to
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