Specifications

Camera Maintenance
The G3 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 G3 and G4 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 small cylindrical chamber, 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 bake the wet silica-gel in the oven (not the microvawe one!) to
dry it again. Dry the silica-gel for one hour at 150 to 160 °C. Exceeding the
170 °C can damage the silica-gel and its ability to absorb moisture will be
limited.
The silica-gel used in G3 and G4 cameras changes its color according to
amount of water absorbed – it is bright orange when it is dry and turns to
transparent without any color hue when it becomes wet.
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