Prism and Celestron GGX-L mount

Questions and answers about the best way to get started with Prism including: est hardware to use, software settings, etc..
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jelake@harbornet.com
Posts: 4
Joined: Wed Jan 15, 2020 4:33 pm

Wed Jan 15, 2020 7:05 pm

I have a new Celestron CGX-L mount that I want to get working with Prism. I have attempted to make Prism talk to the the mount by connecting it to the USB mini connection on the hand controller. When I plug in the USB cable to my Win10 (64bit) laptop, the dialog tells me it can't see the serial port. What pops up upon connection is the USB-serial controller which claims there is no driver installed. I directed Windows to the ASCOM driver that I downloaded, but Windows doesn't recognize that as a valid driver. I tried the old Celestron Nex software, but it will not install in a 64 bit system.
Does this mean that Prism does not work with Celestron mounts? Has anyone else encountered this issue? It seems to me that this is a serial to USB issue. The hand controller must output a serial data stream that needs a serial to USB converter or a serial to USB driver. Win10 apparently does not ship with a serial to USB driver. Does anyone have any idea what driver might work?
John Monroe
Posts: 39
Joined: Thu Dec 06, 2018 7:17 pm

Wed Jan 15, 2020 10:14 pm

Hi Jelake, I might be able to help you. I have the same mount I bought last June. I have no problem running it with Prism so yes it does work. When you go into settings, hardware setup do you see this screen?
Choose ASCOM compliant then choose telescope mount.
Screenshot (3).png
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Screenshot (4).png
John Monroe
Posts: 39
Joined: Thu Dec 06, 2018 7:17 pm

Wed Jan 15, 2020 10:22 pm

Also, here is the driver that I have...
https://ascom-standards.org/Downloads/ScopeDrivers.htm

Celestron Unified (6.1.70594, May 2019) Telescope & Focuser
Download

Installs a driver for all computerized Celestron telescopes, now including the new Celestron Focuser. NOTE: With this version, Focuser moves are prevented if the focuser is not calibrated. Calibrate before anything else! This driver has passed the Conformance Checker tests. See the help file and release notes(!), installed as part of the driver, for a full description.
jelake@harbornet.com
Posts: 4
Joined: Wed Jan 15, 2020 4:33 pm

Thu Jan 16, 2020 10:53 am

John ,
How nice of you to reply. I am very happy to hear that someone else has made the CHX-L work with Prism. This problem must be related to my procedure or equipment. I downloaded the very same driver and I attempted to install it in the same way. Without success.

What sort of computer are you using? Is it windows 10 (64 bit)?

Are you using NexRemote software?

Is your mount connected thru the mini USB port on the bottom of the hand controller, or the USB-B port on the side of the mount?

When you plug in your mount to a USB port on your computer, does it automatically select a COM port? Which one? Does that port selection show up in the little dialog within Prism (the screen capture you posted?) Does Prism read data from the ASCOM platform and fill in the blanks?

Does the Windows Device Manager show that ASCOM driver as being assigned to that COM port?

If your mount works, then mine will work, I just have to find out what is amiss in my system.
jelake@harbornet.com
Posts: 4
Joined: Wed Jan 15, 2020 4:33 pm

Thu Jan 16, 2020 12:53 pm

I did manage to make a connection to the telescope. I think that there may be a bad connection somewhere. I any event, the connection was on COM6 and looking at that port in the Device Manager I note that it is using a driver called ser2pl64.sys. It does not show the ASCOM driver, which I believe is called ASCOM.Celestron.exe which is stored by default in Program Files(x86)>Common files>ASCOM>Celestron.

Is that the correct driver? Is it in the right location? I tried to switch drivers to the ASCOM driver and Windows would not let me do that. The ser2pl64.sys driver does seem to work. I can point the telescope with it using Prism.

Any additional info on these drivers would be very much appreciated.
John Monroe
Posts: 39
Joined: Thu Dec 06, 2018 7:17 pm

Fri Jan 17, 2020 6:56 pm

I am not terribly knowledgeable about things like drivers and where they are stored. I have struggled myself on some things but have managed to get up and running. I will help you as much as I can. It sounds like you are up and running with your mount or are you still having issues?
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