Astrel Instruments AST183-X
Using the vacuum pump
The camera adopts a low vacuum approach to avoid frosting on the CCD glass, filters and
optical window. Using the included vacuum pump, you can remove the air from inside the
camera, so that there's no more water vapor to freeze on the CCD glass and filters. Moreover,
reducing the air inside the camera minimizes the heat exchanges due to convection, so the
optical window never get too cold due to the low CCD and cold finger temperature. The included
pump is typically able to reach about
25-26 inHg
vacuum in less than a minute of operation, but
anything above 24 inHg is enough. The vacuum pump gauges have a tolerance of about +/- 1
inHg, refer to the “Important Notice” sheet provided with the camera to get the proper vacuum
level to be set before cooling the camera. The camera is tested to maintain a vacuum better
than 24 inHg for at least two days and it's not unusual for cameras to last for weeks, so there's
no need to operate the pump during a photo session.
Always keep the vacuum valve closed even when the camera is not working. When the camera
is not used for long periods, it is advisable to put it into an air tight envelop.
WARNING: never get the camera below the freezing temperature without evacuating it to an
acceptable vacuum level: you will run the risk of frost creation on the CCD glass and even
produce a permanent damage to the camera.
Getting Started 11/19 rev A
