Weird behavior of my AP400 mounts

Pawel Lancucki


I am just back from a small star party under extremely clear skies in
southern Poland. The sky was crystal clear but large temperature drops in
relatively humid air caused heavy dew. At the end of each night, all
equipment was literally dipping with water. However, it was dried
thoroughly the subsequent day.

The setup was working fine for the first two nights - as expected from AP
;-) The third night, my AP400 mount behaved in a really weird way. When
commanded a GOTO from PC, the mount would move in RA only - no movement in
DEC. Movement in RA was as usual - on spot. Position was reported properly
in TheSky, no error messages were shown. I have approached the mount and
tried to move it using handpad or to command GOTO from there. Results were
the same - no movement in DEC, no yellow light on the GTO panel. All
cables were seated properly.

After checking and re-seating the cables and recycling the power, the
mount started to operate normally.

Can this behavior be attributed to the dew / moisture or should I check /
clean cable connections? Or maybe someone would have other recommendations
or suggestions?

My initial thinking was that the light should turn yellow in case GTO
controller would not get motion feedback from DEC encoder (and would
assume the axis has stalled). Off course the axis nor motor was in reality
not stalled.

As this is my transportable setup. which I usually use in remote
locations, it is better to check for any possible failures at home instead
of wasting a clear night in the field ;-)

Best Regards

Pawel Lancucki

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