ASCOM Celestron CGEM Mount Issue

The ASCOM Celestron CGEM mount driver will sometimes disconnect for an unknown reason, this happens to me at least once per session. This driver failure will cause SGP to report that it has lost connection to the CGEM mount as well as an error in PHD2 since the mount is no longer available. I recover by pushing the ‘connect’ button on the equipment menu and then reconnect the mount within PHD as well - this is a problem when I leave the session unattended because I am not there to perform this reconnect manually. Has anyone else seen this issue or know of another solution to this particular problem ?


I don’t have a Celestron mount, but seeing that nobody else has responded yet I’ll throw out some ideas.

Connection dropping issues are sometimes caused by faulty cables or connections. It may be a good idea to try swapping cables, using different USB ports on your PC and/or USB hub, and trying eliminating USB hubs or USB extender cables.

If none of that works, you’ll need to contact the ASCOM driver maintainer. Be sure to provide the ASCOM driver logs when you do.

You could also post your SGP log and PHD2 debug log and we could see if there is any information in there about the dropped connection. I’m not very optimistic that we would find anything useful there since the problem is happening “below” SGP and PHD2, but it is worth a look.


My guess would be a bad USB to serial cable and/or driver. They’re pretty finicky. I used to have a CGEM and used it with SGP… it worked fine back then.

You can go into the ASCOM driver and turn on more advanced log files… they might help you track down what’s going on too.

I’m using a Celestron CGEM-DX mount, it uses the same ASCOM driver, and while the mount is driving me to distraction, disconnects in SGP and PHD2 are not an issue I’ve seen, so I feel compelled to agree with everyone else that the issue is likely mechanical/electrical and not with the software at all.

The fact that it reconnects with just a button push suggests something that’s only slightly bad… a broken wire inside the USB cable or a loose USB hub connector, perhaps.

Also, depending on the weather where you are, cold temperatures can make most USB hubs intermittently unreliable. (I’ve taken to keeping mine warm with a reptile aquarium heater.)


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