[g__day (Matthew)]

I have only seen this happen once before (and there is a thread about this on the ZWO forums - the attempted resolution seems to be update the firmware.

The issue is when the temperature is between 23 - 26 Ceclius (like right now) the ZWO focuser (EAF) temperature probe can shift like a pendulum over a 1 - 2 minute cycle reading between 16.2 and 22.4 degrees.

I see the temperature readings fall to 16.2C - at around 0.1C every 1-2 seconds - then when they hit 16.2C they rise at the same rate until they get to 23C - then they fall and the process continues over and over and over!

My software has a trigger saying if temperature varies by 0.5 C trip and autofocus and otherwise adjust focus every 0.1 C automatically by 4 steps.

So I noticed too many autofoucsers then I looked at the temperature on my focusers. The Moonlight focuser on the scope clled by SGP is reporting a rock steady 24 degrees - the ZWO controlled by APT is seeing the ZWO change temperature by 0.1 degrees every 1-2 seconds!

So I turned both temperature compensation and refocus on 0.5 degree temperature changes off in APT.

Have other folks witnessed this and did the firmware update 1) succeed and 2) solve the problem.

The ZWO thread has a user measure the 100K resistor they use and point out the exact problem there - dating back over a year!

Many thanks,

Matthew

PS

Switching to Autofocus on filter change - where I am running Luminance 3 x 5mins, Red 3 x 5 mins, Green 3 x 5 mins and Blue 3 x 5 mins - so rather than autofocus (which takes 2-3 mins) every 30 minutes - I am trialling doing it every 15 mins now to see what that does to my image quality - using ASTAP to compare!