Do I need the Ascom Hub for SGP?

Hi, I am about to buy SGP pro and I have a question about connecting my devices.

I will be using Plate Solving, autoguiding, planetarium functions in SGP.
All modules will send commands to my mount. Can they be combined by SGP and send the combined signals to the mount driver? Or am i going to need the POTH hub from Ascom to have the signals combined?



That really depends on your mount’s ASCOM driver. However almost all mounts don’t require the use of a hub. I can’t think of one that actually requires it to be honest, but it did used to be a problem.

If you haven’t started a trial yet, grab the release from our downloads page and give it a shot.


Thanks Jared,

you are right ofcourse with your advice to try it out myself. But at the moment I am repairing/rebuilding my power supply and my Astro laptop for a new start of my astrophotography hobby, So I have no working setup at the moment. Buying SGP is part of this new start. In the mean time I am trying to gather information.

My mount is an Vixen GP with MTS-3 controller. I have a working Ascom driver for this controller. When I was using this with Cartes-du-Ciel planetarium and Elbrus plate solver I had to use the Ascom POTH hub to be able to use both software in parallel.
I am wondering if SGP can fullfill the role of the Hub?


If the ASCOM driver for your controller can accept multiple connections, you should be able to use CdC to slew and SGP to slew/center too. SGP is not a hub itself. You may need to ensure that all applications accessing the mount have the same privilege. I set all mine to Administrator and I have no issues.

No, this is entirely up to your mount driver. SGP does not expose an ASCOM driver so you wouldn’t be able to connect other applications to your mount through SGP. If your mount driver is well written then you should be able to connect multiple applications to it.

Needing a hub, or not, is completely up to how your mounts ASCOM driver was written and not up to the connecting applications.


Thanks buzz and Jared for your answers. I now realise that i didnt communicatie clearly enough. Let’s clear it up:

From previous test (e.g. with PHD + Cartes-du-Ciel) I know that the Ascom driver of my mount (MTS-3 driver for Vixen GP) cannot accept simultaneous connections from more than one application.
Using the Ascom POTH Hub was sort of a solution but it was critical with the order in which to connect the various components. So I prefer not to use the POTH hub.

Now with SGP i am hopefull that all components that need to talk to the mount driver (PHD, Goto-command from SGP, maybe a handcontroller) do that through SGP, not directly. That way, I wouldn’t need the POTH. What do you think?
I called that a hub functionality because SGP would need to combine the signals from PHD and its own Goto command, but that is not a proper term I guess.
So I don’t want to connect CDC + SGP to my Ascom driver, just SGP.


I guess that depends on how you’re guiding. But since you had PHD connected to your mount before I’m guessing you’ll still need PHD connected. So PHD + SGP will need to be connected to your mount, thus you’ll need POTH since your mount cannot handle multiple connections.

The exception to this would be if you didn’t need PHD connected to the ASCOM driver and you used ST4 guiding (ie “On camera”) rather than pulse guiding.

So it seems you’ll probably still need POTH as PHD does not send guiding commands through SGP. They are sent directly to the mount.


Thanks. Clear.