Newbie: Gemini 2 and SGP


I am working with a Titan running Gemini2 and SGP. I have been working on the tutorials with the virtual scope adn etc, am wondering about interactions between the two. Specific actions below.

I assume that I should pick a park position using Gemini2. Here is what I would do, following Gemini2 protocols.

  1. Start the Titan in CPD position.
  2. Slew and Synch on a star without entering it into a Gemini2 model.
  3. Set the park position to 0-180 (tube horizontal and pointing south.
    4, Place the mount in park position.

Now, the interaction questions.

  1. When I open SGP and then open within SGP, will SGP “know” my park position?
  2. If so, do I unpark it in Gemini2 or in SGP using the sequence window?
  3. Once unparked can I then command SGP center on, say, Vega and assume that I am plate-solved and ready?
  4. Or do I simply center on my first target?

Thanks for helping a newbie,


SGP doesn’t “know” anything :slight_smile: It simply issues commands to the ASCOM
driver ( in your case). When SGP completes the sequence
it simply issues a park command to Gemini2. So wherever the park position
is set in is where the mount will park.

As far as start up goes, here’s what I do:

  1. Connect the mount and if necessary unpark from the ascom driver
  2. Slew somewhere in the sky away from the pole (either with a planetarium
    program or with the on screen control)
  3. “Solve and Sync” the mount.

At that point you should be good to go.


Many thanks, Joel, that sound pretty simple.



Joel: Are you working remotely? One of my goals is remote operation. If I do it your way I need to figure a protocol to “unwind” the scope after park. I was hoping that I could issue a slew commend after unparking, but I suspect that since there is no model in the gemini system I doubt it knows where it is.



If you park the mount and power down, then power up and unpark the mount
Gemini will know where it is. At least it will be close. A model isn’t as
necessary as it once was with the advent of plate solving. Even if you’re
initial slew is off a little, plate solve and sync will get it dead on.

I’m not technically working remotely (home observatory) but except for
physically turning the power switch on I could do everything remotely. I
used a G11 Gemini-2 for several years before recently moving to a
Mach1GTO. But the basic functions are all the same. I park the mount at
the end of a sequence and turn the power off. Next night I simply turn the
power back on, connect to the mount, slew to a star, and solve and sync
from SGP. I could do all that from inside my home or from 1000 miles away.


Excellent, many thanks Joel. This is a great help.


Hey Ed,

I just shut down my first observatory and I’m setting up my second as we speak. I run a Gemini-2 powered Mi-250 (similar to a Titan) so I think I can speak your lingo.

First off, lets assume you’re already polar aligned and you have chosen an appropriate park position. The ASCOM driver allows you to create park positions in a variety of methods. My previous setup required me to have my scope side ways in order to close/open the roof. So, lets assume you have that defined already as the home position (LMK if you don’t and I can talk you through that too). You won’t need a model since you’re using plate solving so don’t worry about that part. When I turn on my Gemini-2, I would select ‘warm restart’ if I was in my ‘home’ position. If I was messing with the scope and had it in the CWD (Counterweight Down) position, I would choose either Cold start (dump the model, CWD), or Warm start (dump the model, keep most of my settings). Again, you don’t need a model if you’re polar aligned.

OK, from there, I started SGP and told it to do it’s thing. Often the first plate solve takes awhile because it might be off a bit, but beyond that it’s just good to go. I always used ‘slew’ and ‘center’ for my targets. That way, SGP knows to issue a ‘slew’ command and the target is always roughly in the area. Otherwise, if for instance you’re at CWD, SGP tries to plate solve and it can get some wonky results near the pole that can really mess things off. So, I always ‘slew’ and ‘center’ for all targets.

You do not need to unpark your mount. SGP will issue an ‘unpark’ when it starts the sequence. If you are doing things manually, you will need to do an unpark (I always used the ASCOM hand controller) and then issue the slew or nothing will happen.

I ran remote for 3 of the 5 years I had my ROR. I did it from around the world and have quite a bit of lessons learned. Gemini-2 is very survivable and works really well. I sometimes see that the model will get corrupted; you just need to park it CWD and then do a cold restart and it will come back without any issues. The corruption is usually due to a bad plate solve.

Good luck,


Many thanks, Chris, this is exactly the kind of information I need.

BTW: I have had success in setting the scope to the home position, which for me is OTA horizontal and pointing S on the East side to the pier (0 Alt, 180 AZ), so I can do that. I am assuming that the warm restart uses the last successful plate solve to determine where the scope is at park when its restarted. Is this correct?



Yup. It basically saves the last position of the scope and will start it back up from that location.