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CCD telemetry out of range

If the temperature is out of range (CCD warming up), fill immediately. SITe2 has an off-centre filler tube which means that at very high and very low ZD's, then liquid Nitrogen can syphon out, rapidly reducing the hold-time. The danger is under-filling the cryostat: continue to fill until liquid Nitrogen is seen escaping from the filler tube or side vent. If the 5v digital line goes out of range, ignore it, but log it in the database.