Hi Folks,
I recently purchased a SharpSky Pro motorised focusing kit, and am quite impressed with its operation. Manual focus operation is still very simple using the setup, and autofocus works a treat from TheSkyX using @Focus2 or @Focus3.
But going through calibration for automated temperature compensation, something has me a bit stumped.
As my scope (Esprit 120 triplet) cools, the focuser need to move INWARDS slightly to maintain focus ... by approx 50 steps per degree of temperature drop.
I expected the focuser would need to move OUTWARDS to maintain focus as the OTA cooled/contracted.
Has anybody else had a similar experience?
Could this be normal for a triplet ... with focal length maybe decreasing slightly as the temp drops due to changed spacing of the elements?
Of course, I may have made a stupid mistake somewhere.
The laws of physics seem to be conspiring against me.
Explanation sought .... so I can sleep.
