Re: Moravian Instruments C1x/C3-61000 and 26000
Posted: Fri Oct 16, 2026 4:18 pm
Ah! I talked to Moravian guys today and totally forgot to mention that they have this wrong in camera manual, I knew there was one more thing 
It is correct in Driver and Software manual though (of course I only found it after I went through all that hassle with checking which files are being read).
https://www.gxccd.com/download/Drivers% ... ftware.pdf
Changing subject: I noticed that SharpCap uses wrong GPS timestamp with Moravian cameras (well, I only checked with C1x26000 really). Moravian cameras timestamp the exposure start, and what is saved in FITS header differs from reality by a single exposure length, which I guess is because you assume that received timestamp indicates the end of exposure, like it's with QHY cameras.
Also, we verified that there's about 0.2s time offset on top of what i mentioned above, which suggests that what is saved as GPSST (or similar name, I don't remember exactly, but it's supposed to be GPS timestamp of exposure start) seems to actually be current GPS time (so not time when exposure actually started, but when image got to PC more or less I think). It seems to me that you're extracting time from cameraGetGPSData or cameraGetGPSData2 call instead of using cameraGetImageTimeStamp - but that's just from observing the behaviour and reading SDK documentation.
It is correct in Driver and Software manual though (of course I only found it after I went through all that hassle with checking which files are being read).https://www.gxccd.com/download/Drivers% ... ftware.pdf
Changing subject: I noticed that SharpCap uses wrong GPS timestamp with Moravian cameras (well, I only checked with C1x26000 really). Moravian cameras timestamp the exposure start, and what is saved in FITS header differs from reality by a single exposure length, which I guess is because you assume that received timestamp indicates the end of exposure, like it's with QHY cameras.
Also, we verified that there's about 0.2s time offset on top of what i mentioned above, which suggests that what is saved as GPSST (or similar name, I don't remember exactly, but it's supposed to be GPS timestamp of exposure start) seems to actually be current GPS time (so not time when exposure actually started, but when image got to PC more or less I think). It seems to me that you're extracting time from cameraGetGPSData or cameraGetGPSData2 call instead of using cameraGetImageTimeStamp - but that's just from observing the behaviour and reading SDK documentation.