ASCOM and ST4

[Goschencat (Rex)]

A newbie question.
If your EQ6 mount is setup and connected via USB shoestring cable to ASCOM, and you use PHD for guiding with a seperate guide scope and camera, do you need the ST4 port on the guide camera connected to the guide port on the mount at all ?

It's just that I'm a little confused as to how the guide commands get to the mount. Are they via the ASCOM cable connection or via the ST4 port on the camera ?

Thanks for any advice here.

[kens (Ken)]

Either can work.
I'm assuming the USB shoestring cable is the EQDIR.
The ST4 option allows PHD to send the guide commands to the guide camera through its USB port by setting the Mount to "On-camera" and the camera then passes them onto the mount through its ST4 port. If you also connect your mount it wont get guide commands through the EQDIR cable but it can tell PHD where its pointing if it is connected as an Aux Mount.

Alternatively, you can connect PHD directly to the mount through the EQDIR cable with Mount EQMOD ASCOM HEQ5/6 and send the guide commands through that cable. The camera then acts just as a camera so you don't need the ST4 cable.

[Goschencat (Rex)]

Thanks Ken,
Is one method any better than the other for some reason ?
Other than if you didn't use the ST4 method that would mean one less cable to risk getting caught up perhaps.

[kens (Ken)]

One less cable is one less thing to go wrong. So once you go down the path of connecting computer to mount I think it makes sense to drop the ST4 cable.
Connecting the computer to the mount opens up new possibilities aside from guiding. In my case I use Stellarium to slew the mount to the target then use AstroTortilla to plate solve and make the necessary adjustment to centre the target.
It also lets you use a guide camera that doesn't have an ST4 port.

[jenchris (Jennifer)]

I'm sure I posted on this thread but it has gone.
However the posts here seem to cover it.
If my post was deleted, I would be interested in the reason.