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Paul Abel

Joined: 15/07/2022
Messages: 4
Location: GA, USA
I just purchased an Argo Navis which is now on its way to me. The reason for this purchase is to allow me to control my Dobsonian, which already has a ServoCAT version 3, by a PC using an ASCOM driver. My goal is to do to EAA with this scope and find targets using a PC planetarium program and then the Platesolve (Sync Mount and Re-centre target) function of Sharpcap.

Reading the AN manual, I understand that I can connect one of the AN serial ports to an LX-200 ASCOM driver on my PC by using the “meade” startup command in the AN’s SETUP SERIAL function. While I can then fill in the AN’s “FROM PLANETARIUM” catalog entry from a pc planetarium program, in an earlier post on this forum, Gary says that in order to then initiate a GOTO to those coordinates I would have to “press the GoTo button on the ServoCAT handpad.” https://www.wildcard-innovations.com.au/forum/posts/list/61.page Since I can get a wireless handpad for the ServoCAT. I can live with that.

The ASCOM drivers I have seen often come with a “virtual handpad” that will allow you to move the scope directly from the PC. Does anyone know whether I will have such functionality if I am using an LX-200 ASCOM driver connected to the AN? Or will I again have to the use the movement buttons on the ServoCAT handpad?

And if, after I do the GOTO, I then use Sharpcap’s Platesolve function and want Sharpcap to send an ASCOM Sync command to the AN/SC based on the plate solving results and then perform a re-GOTO to the original co-ordinates, will this work? If all I would have to do is press the GoTo button on the SC handpad after the platesolve, I could live with that.

If the Sharpcap Platesolve function will not work with the LX-200 ASCOM driver, then I know I can connect the USB port on my ServoCAT to a USB port on my PC and then use one of the two available ServoCAT ASCOM drivers. But I would like to use a wireless connection between the scope and the PC, and I am wondering if and how I can use the AN to make the connection with the ServoCAT ASCOM driver on the PC (by attaching a serial to Bluetooth adapter to the end of the AN serial cable).

So, my last question is whether any of the startup commands in the AN’s SETUP SERIAL function (in particular, “servocat” or “navis”) would allow me to use the AN as a “conduit” between the ServoCAT ASCOM driver and the ServoCAT?

Thanks in advance for any assistance!



Joined: 17/10/2019
Messages: 122
Location: Mount Kuring-Gai NSW Australia
Hi Paul,

Thanks for the post and welcome to the forum.

When using the ServoCAT with Argo Navis the recommended wiring topology is :-

PC <-> ServoCAT <-> Argo Navis

By way of background Wildcard Innovations collaborated with StellarCAT in the development of the ServoCAT communications protocol.

In the topology above, the PC interacts with the ServoCAT via the ServoCAT's PC port. Command that need to go to the Argo Navis are then relayed to and from it.
For example, when the PC planetarium sends a command to fill the FROM PLANETARIUM catalog entry, it is relayed by the ServoCAT to the Argo Navis.

Meanwhile, the continual communication flow between ServoCAT and Argo Navis is also happening.

The communication that occurs between the Argo Navis and the ServoCAT is a subset of the ServoCAT protocol. Additional commands are available between the PC
and the ServoCAT.

I do not know how the Sync command on the ServoCAT ASCOM driver(s) have been implemented.

What I would do is after the plate solve, you know the astrometrically determined RA/Dec of where you are pointing.
One could transmit those coordinates to the Argo Navis FROM PLANETARIUM object and then one could go into MODE ALIGN and align on them.

If you connect the planetarium program directly to the Argo Navis and use the ServoCAT protocol, driving the ServoCAT will not work in that way.
The ServoCAT and the ServoCAT protocol are designed to relay data via the path PC <-> ServoCAT <-> Argo Navis and not PC <-? Argo Navis <-ServoCAT>,

One can also use the second Argo Navis serial port to connect to the PC and have it configured to run the "meade" protocol and that also allows for filling of the FROM PLANETARIUM
entry and fetching of the RA/Dec position but it won't control the ServoCAT in that way.

The Meade protocol includes the "CM# cakibrate command. If Argo Navis happens to be in MODE ALIGN STAR or MODE ALIGN or MODE FIX ALT REF when it is issued, it will be perform
the equivalent of hitting he Enter button on the Argo Navis.

I am sure I have not answered all your questions so feel free to ask more, but I hope the insight into PC <-> ServoCAT <-> Argo Navis being the recommended topology when
using the ServoCAT protocol is helping point you in the right direction.

I see you are also on the ServoCAT GroupsIO group which is a good resource as well.

Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place
Mount Kuring-Gai NSW 2080
Phone +61-2-9457-9049
[Email] [WWW]
Paul Abel

Joined: 15/07/2022
Messages: 4
Location: GA, USA
Thanks Gary. A lot of good information here. Let me experiment with my system once the AN arrives and then I may very well be back here with more questions.



Joined: 07/10/2022
Messages: 1
Location: NYC USA
interesting information
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