Eq3 and PHD

[Simon B]

Hi

I am just starting out on guiding and am planning to use a 50mm guidescope on my Skywatcher 150p with a webcam (initially). I have dual axis motors on my Eq3-2 which I plan to connect directly to the pc (not to the guide camera) using PHD.

I am just playing around with it at the moment and can see that in PHD I need to select the webcam and mount. I assume I am selecting the windows webcam from the drop-down, but the mount appears more difficult. I assume I need to install ASCOM to get PHD to talk to the motors, but the EQMOD appears to be for Eq3 goto only. 

Does anyone have any ideas about which ASCOM drivers would be usual for an Eq3 with just dual axis motors?

Many thanks

Simon

[Cornelius Varley]

Do you have the enhanced dual axis handset ?

[Simon B]

Hi Peter - yes I do, so as far as I can see it does not require modification.

[Cornelius Varley]

The handset cannot be connected directly to the computer so you will need an autoguider interface . 

[Simon B]

Yes thank you, much appreciated, I do have something of that sort from China. The issue I have is the ASCOM drivers for the EQ3 - do you know what would be applicable?

[lenscap]

There is no Ascom driver for the EQ3-2 enhanced dual-axis kit because it has a "dumb" controller which has no communications facility.

If you are into DIY you could build an Onstep or AstroEQ controller, with new stepper motors,which would give your mount a full GoTo capability for about a third of the cost of the EQ3-2 GoTo upgrade kit.

https://groups.io/g/onstep/wiki/home

https://www.astroeq.co.uk/tutorials.php

(While it is possible to use the existing motors the maximum slewing speed would be painfully slow.)

[Cornelius Varley]

1 hour ago, Simon B said:

Yes thank you, much appreciated, I do have something of that sort from China. The issue I have is the ASCOM drivers for the EQ3 - do you know what would be applicable?

The autoguider should have a suitable ascom driver. The mount doesn't need one in this instance because PHD is controlling the USB-ST4 device.

[Simon B]

Hi - this is somewhat confusing as there seems to be two opposite bits of advice! I have seen various posts where people are using EQ3's to guide with so I don't really understand if that is not possible! Thank you

 

[lenscap]

You can of course guide your EQ3-2 through the ST-4 port on the Enhanced Dual-Axis Drive Kit with a suitable interface as explained by Cornelius Varley, but you cannot control the mount directly through ASCOM.

[Cornelius Varley]

19 minutes ago, Simon B said:

Hi - this is somewhat confusing as there seems to be two opposite bits of advice! I have seen various posts where people are using EQ3's to guide with so I don't really understand if that is not possible! Thank you

 

I don't think either me or Lenscap suggested that guiding an EQ3 was not possible. If your handset is like this one in the photo below then you need a USB-ST4 autoguider interface to connect between the computer and handset

The ST4 cable connects between the autoguider port on the handset and a USB cable between the USB-ST4  and pc.  To use it you will need the ascom platform and the ascom driver for the USB-ST4 interface.

[Simon B]

Thank you. Does that mean that the USB-ST4 interface has a specific driver on the ASCOM platform? If so, do you know its name so I can make sure I get the right driver. Thank you.

[Cornelius Varley]

3 minutes ago, Simon B said:

Thank you. Does that mean that the USB-ST4 interface has a specific driver on the ASCOM platform? If so, do you know its name so I can make sure I get the right driver. Thank you.

The manufacturer of the USB-ST4 interface should have that. Do you have a link to the device and are you sure the item you got from China is suitable ? Autoguider interfaces provide electrical isolation between the pc and mount, they are not just an adapter between two types of plug.

[Simon B]

Makes sense. I haven't received it yet so I guess I will find out. Thanks for your help.

[Simon B]

This is the connector:

 

 

[Cornelius Varley]

It might use either an ascom driver from the manufacturer or a windows usb hid (humam interface device) driver.

[Simon B]

Thanks for that, much appreciated.

[Cornelius Varley]

You might find that the ZWO USB-ST4 ascom driver will work https://astronomy-imaging-camera.com/software-drivers. In PHD2 select windows wmd webcam and then ZWO USB-ST4 for mount type.