NigelHt

It isn't set to connect on app launch, so I launch it and then click "connect" - which is when I get the failure message. The COM port is stored correctly, though, and I recall looking in "device manager" and seeing it there before attempting to connect.

I believe it's FTDI; there's no issue with the port number (and it is indeed the same every time) because EQMOD and the App are both set to use the same one, and indeed I have checked that it is present in device manager even when the connection fails.

I'm seeing a strange issue when trying to connect to my HEQ5 mount using the Synscan Pro App running under Windows 11 and an EQDIR cable direct to the mount. All drivers etc are installed. (The reason I want to use the app is because it provides better tracking of the ISS using Skytrack that is possible with EQMOD.) If I power everything on, run the app and then hit "connect" I get a failure message, and this is repeatable. However, if I connect to the mount first using EQMOD from, say, CdC (which never fails) and then disconnect, the app will always connect. I'm not sure that it's always been like this, so it may be something to do with the sequence of powering on, connecting, etc, but if so I haven't managed to discover what. The only other thing to mention is that the USB connection goes via a USB hub (I don't have enough USB ports to avoid this), but as I said, it works first time every time with EQMOD. Obviously the workround I've mentioned is pretty simple to do, but it's a nuisance to have to do it every time. Has anyone else experienced this and found a solution, please?

I could do that, but the problem isn't with PHD2; if I manually drive the mount north, stop, south I see exactly the same "wrong way" movement. Nigel

I believe there is an option for this, but I've not used it as this is what PHD2 advises. Nigel

I've recently started astrophotography, and after beginning with a DSLR and rotator haveprogressed to an EQM-35 GoTo mount and Zenithstar 73 telescope, with Ascom control and guiding with PHD2. While I've got some decent results, I've consistently had problems with guiding, even though I've tried adjusting the mount as described in online videos to remove backlash, and unbalancing the telescope. Initially there was obvious backlash that I could feel; I've now eliminated that, although I notice that the stiffness varies with declination (something I've seen reported by others), and it's almost impossible to avoid backlash at some declination angles without making the mount far too stiff at others. While I'm aware that this type of mount is always prone to backlash issues, what I'm seeing is still different to what I'd expect. If I drive the mount, say, North (either manually or as part of calibration or guiding), stop so that everything comes completely to rest, and then drive the mount South, what I see is that it continues to move North for a while before beginning to move South as expected; the behaviour is exactly the same if I start moving South then switch to moving North. The attached image is part of a typical calibration from PHD2 Log Viewer to show what I mean. As you can imagine, this completely messes up guiding unless I offset the polar alignment and guide in one direction only, or align very accurately and switch off declination guiding altogether. If this was simply backlash, I'd expect the mount not to move at all initially after switching direction rather than to move the wrong way, and I can't think of a mechanism to cause this behaviour. I'd be grateful if anyone can explain this, please, and give me some advice on how to cure it.