Autofocus stopped working


I currently run SGP with a Celestron focus motor for autofocusing. I had a bit of trouble getting it setup initially but eventually sorted out driver issues and it was working well for about a month. After a bit of a break due to weather, I finally got a clear night. When I started my sequence the Autofocus would just startup and then hang. The focuser was working fine when I told it to move manually but I was unable to get the autofocus to work. I paste an example of the issue from the log below. It appears there is an error about AF darks… “AF Darks exception: The path is not of a legal form.” Any help is appreciated.

Link to Logs

[01/24/21 22:25:24.673][DEBUG][Camera Thread][NONE] SGM_FOCUSER_AUTO_FOCUS message received…
[01/24/21 22:25:24.678][DEBUG][Camera Thread][AF;] Checking for auto focus…
[01/24/21 22:25:24.678][DEBUG][Camera Thread][AF;] Auto focus required (forced)…
[01/24/21 22:25:24.679][DEBUG][Camera Thread][AF;] Auto focus required (time trigger)…
[01/24/21 22:25:24.691][DEBUG][Camera Thread][AF;] Auto focus: setting filter None
[01/24/21 22:25:24.706][DEBUG][Camera Thread][AF;] Auto focus running…
[01/24/21 22:25:24.729][INFO][Camera Thread][AF;] Performing Sequence Generator auto focus using Half Flux Radius. AFID: 1
[01/24/21 22:25:24.750][DEBUG][AfChartThread][AF;] Showing AF chart dialog…
[01/24/21 22:25:24.751][INFO][Camera Thread][AF;] Auto focus data
[01/24/21 22:25:24.751][INFO][Camera Thread][AF;] - Data Points: 9
[01/24/21 22:25:24.751][INFO][Camera Thread][AF;] - Step Size: 100
[01/24/21 22:25:24.751][INFO][Camera Thread][AF;] - Current Position: 4912
[01/24/21 22:25:24.751][INFO][Camera Thread][AF;] - Initial Move Position: 5312
[01/24/21 22:25:24.751][INFO][Camera Thread][AF;] - Panic Move Position: 4912
[01/24/21 22:25:24.950][ERROR][Camera Thread][AF;] AF Darks exception: The path is not of a legal form.
[01/24/21 22:25:24.952][INFO][Camera Thread][AF;] Moving focuser to next position (5312)…
[01/24/21 22:25:24.953][DEBUG][Camera Thread][AF;] MoveFocuserAbs: Start, move to 5312…
[01/24/21 22:25:24.953][DEBUG][Camera Thread][AF;] ASCOM Focuser: MoveSync - start…
[01/24/21 22:25:24.956][DEBUG][Camera Thread][AF;] Focuser moving to 5312
[01/24/21 22:25:24.959][DEBUG][Camera Thread][AF;] Focuser move call complete
[01/24/21 22:25:24.960][DEBUG][Move Monitor Thread][AF;] ASCOM Focuser: Move monitor thread is started…
[01/24/21 22:25:27.962][DEBUG][Move Monitor Thread][AF;] ASCOM Focuser: Move monitor thread -> movement complete
[01/24/21 22:25:59.340][DEBUG][Camera Thread][AF;] ASCOM Focuser: MoveSync abort detected!
[01/24/21 22:25:59.351][DEBUG][Camera Thread][AF;] MoveFocuserAbs: End, move complete, at 5368…
[01/24/21 22:25:59.352][INFO][Camera Thread][AF;] AF abort requested
[01/24/21 22:25:59.355][DEBUG][Focuser Thread][AF;] SGM_FOCUSER_MOVE_ABS message received…
[01/24/21 22:25:59.355][DEBUG][Focuser Thread][AF;] Focuser moving to 4912
[01/24/21 22:25:59.361][DEBUG][Focuser Thread][AF;] Focuser move call complete

Useful Info

OS: Windows 10 Home
Ver: SGP

it is possible the path has some characters that don’t work well with apps… what if you take your AF darks and put them in a folder structure without special characters?

Do you really need AF darks… I do not think I have ever used them.

I am actually not even using AF darks. I checked the setup to verify that was the case - so I really dont understand the error.

I had the exact same issue. I could never resolve it. I changed to a different focuser and never had an issue since. From what I could tell the Celestron Focus Motor would not send the signal that it reached the desired position. It would always stop signaling a few steps before. To me it looked like an ASCOM driver issue so maybe in the future it will be resolved.

I’m note sure if this is the same problem I had, but I experienced intermittent hangups with the Celestron focus motor and it seemed to be either linked with the USB port. If for any reason, my CGEM mount was reset, I had to reboot the Mini PC to get the focus motor to work. The other problem was with the USB cable and after replacing it, that got rid of the hangup problem too.

Hope someone is able to find a solution for you!

Clear Skies

USB hubs, cables and initialization are the biggest culprits of unexpected failures. With mini PCs, running on 12 Volts - be careful about turning a mount off and on too - the current surge is sometimes sufficient to drop the voltage and hang up electronics. The NUC pcs for instance have a min 12V requirement and I can stop mine when I turn on the Paramount.