iOptron Go To ZERO position

minor request but useful for iOptron mount owners.
Is it possibile to develop the “Go To ZERO” action for CEM mounts?
It’s very similar concept as “Home” position for Paramounts.

The iOptron mounts are ASCOM driven.

Thanks in advance.

1 Like

Voyager interface to mount have a method dedicated to home … now is implementend only for TheSkyX Mount. ASCOM doesnt have this method but if you can understand which is the commandstring to send to mount i can add to ASCOM adding a flag in setup for IOptron.

Let me know when you found this command, i think the best is to found ioptron docs or ask directly to their developer.

All the best

I have an iOptron CEM60 mount so I looked this up. The command is:

Command: “:MH#”
Response: “1”
This command will slew to the zero position (home position) immediately

And the command document is here:


Thanks a lot. I have a CEM 120 EC.

Nice mount! I have a CEM60 and a MyT, Voyager runs them both very nicely.

What rig do you have on the CEM120? Always wondered how much imaging weight it can handle reliably.


I also using a Paramount MX with a ASA Newtonian, the Home command works perfectly thought TSX. The only one thing I hate of this mount is, I can not use SYNC command from Voyager… because TSX is using the pointing model and when I sync, i loose it for the single session. Do you have any workaround for that?

Haha, yes you got the answer on the other post.
Actually I have a 35 Kg load (77 pounds). There are no problems to handle it, you just need a very accurate load balancing. It took about 3-4 hours, moving the single USB cable from left to right and back to find the perfect DEC balance. The losmandy dovetail with graduate scale helped a lot…

Best and thanks to Leo for the great job!

Command: “:MSH#”Response: “1”This command will auto search the real zero position (home position) immediately. This command ignores any current zero position, and designed to be a safe operation in any cases. Currently, only CEM60 and CEM60-EC support this feature.

What about this command ? (only cem60) they have a zero sensor ?

Have you removed the sync from Mount tab in Voyager ? or you remove the model.
10micron have a flag to add sync like point to model … Paramount not yet implemented ?

Yes, I checked "Not Sync … " option in the Mount config.
I will check if Paramount implemented it recently.

CEM60 have a Zero sensor
CEM60 EC have the AR encoder and Zero sensor of course.
CEM120 - CEM120EC - CEM120EC2 have Zero sensor and encorders (ec, ec2).

Based on CEM120EC Documentation, the command line is the same:

Command: “:MH#”
Response: “1”
This command will slew to the zero position/home position immediately.

Command: “:MSH#”
Response: “1”
This command will automatically search the mechanical zero position/home position immediately
by detecting homing sensors. Current zero position/home position will be overwritten by this
operation if the operation succeeds.

Note: This command only available in CEM120 series and CEM60 series mount.
This operation is designed to be a safe operation in any cases.

Let me know if it helps.

You can set your own “zero position” with the CEM60 (and probably the 120, I don’t know for sure).

So you can either search for the hardware’s built-in zero position (:MSH#) or goto your own defined zero position (:MH#).

Maybe in Voyager’s mount setup for iOptron the user can select whether the home command does the “search for hardware zero position” or “goto user-defined zero position.”


ok thank Kristijan and Rowland … i’ll procede in the next daily build.