FITS Header Not Showing Correct Focuser Position


I have been examining the FITS headers of some of my images collected by SGP. During this examination, I noticed that the FITS item “FOCPOS” is always showing the same value; which is different from the value determined by the Auto Focus routines. I am using a Moonlight focuser which is working fine with SGP.

Is this a problem with the Moonlight ASCOM driver or am I overlooking something in my configuration which could be causing this problem. I am running version




Based on the description, it’s difficult to know… We would be able to help you more with the logs from that evening and at least one FITS image taken within that log.


Hi Ken,

Thanks for the response. I apologize for neglecting to attach links to the SGP log and a couple of images. Here are links to the log and two images.

I’ll point out that I was examining the FITS header using PixInsight rather than SGP, if this could make a difference.




Sorry, I think the files you included might not be demonstrative of the issue you are describing (or I am confused).

Right before m27_180sec_-14.8C_frame5, AF arrives here:

[10/23/2016 8:55:05 PM] [DEBUG] [Camera Thread] Auto focus is complete (weighted avg method: 4455; HFR 1.61)…

In the FITS header:

Right before, AF arrives here:

[10/23/2016 9:12:24 PM] [DEBUG] [Camera Thread] Auto focus is complete (best fit method: 4461; HFR 1.72)…

In the FITS header:



I will check these same two files with PixInsight. Perhaps PixInsight is not reporting the correct FOCPOS with its FISTS header examination tool. This could be a PixInsight issue. I’ll report back soon.