Update: Temperature compensation starting temperature doesn't update upon new auto focus


Is anyone having issues with the new temperature compensation change? I have been successfully been using temperature compensation on previous revisions. However, using, I’ve noticed that at the end of an image which immediately follows a triggered auto focus, the normal temperature compensation starts, but it appears to ignore the temperature of the auto focus just completed. It recalculates the temperature compensation starting temperature from the beginning of the sequence, moving it off focus. For example, according to my log, an auto focus runs, perfectly adjusts the focus, then after the next image, Temperature Compensation runs, recalculates the focus from the evenings starting temperature using the temperature coefficient and applies a huge amount. This can immediately move it out of focus by nearly 100 steps on the very next image following the auto focus. E.g., Log 03:01:45 auto focus and log 03:07:47.

I’d appreciate any comments/help. Perhaps it’s operator error (as usual). Here is the link to the log.

Starlight Instruments Focuser Boss II
Windows 10


Bugging temperature compensation by only taking sequence start temperature into account

Hi Phil,

due to bad weather I had no chance to test the revised temperature compensation task before last night. The result is:

  1. The reason for the bug report Temperature Compensation Implementation was, that SGP did not correct properly for many small succeeding temperature changes. The good news is: in this respect SGP’s temperature compensation is working properly now.

  2. Then, according to your post, I tested the interaction of temperature compensation and auto focus runs. I set “Auto focus every 0.5 degree change”. When this condition was met, the corresponding auto focus run was executed properly, but its result was not taken into account at all whith temperature compensation enabled. Temperature compensation continued to refer to ‘start temperature’ and ‘focus position’ of the initially approved auto focus run. (In this respect it is important to note that both ‘start temperature’ and ‘focus position’ have to be updated for the temperature compensation task when an auto focus run has been successfully executed and is approved.)

I hope that the developers will note this flaw and rapidly put things right.




Thank you for taking the time to confirm the issue. SGP overall is working great for me, it’s an automation masterpiece. I hope they can fix this small issue soon. For now, I’ll disable TC in SGP and enable continuous TC in FocusLynx and use it along with SGP autofocus every degree change.



I can confirm problems using AF with I’m finding the same thing happened with my run the other night and also have the same AF system as Phil.



I just had the first clear night since my post to try using the FocusLynx TC with SGP TC off and AutoFocus on - set for every 1 degree. It worked fine, but I’n not sure I trust having the focuser moving during exposures. I hope the SGP TC issue gets addressed in the next update.


Update: I ran release last night and it appeared to run perfectly!! This morning I checked the log files and can confirm SGP’s TC routine is now updating with the AF temp. My AF was approx every 2 hours and the focus position delta between compensated temp and new AF position was very close, averaged < 4 steps. Thank you!

Phil Montgomery