SGP and Pryxis rotator


I just added the rotator to my setup. I was a bit disapointed with SGP interface with it. (limited) Is it possible (and I don’/t know it?) or could it be added where the rotator is displayed over a photo and a plate solve would set the rotator direction?

I shoot a test image and then I want to compose but it’s a bit of a guess without some sort of graphic over lay?



Use the Framing and Mosaic Wizard to pick your rotator angle.



oh let me go look thanks!


Looking at it. I can rotate the image behind the frame.

I get that this will likely work. But it asked me to draw the frame (size).

I’m sure I’m not drawing my actual FOV ? Is there a way to restrict the frame scale

to what I’m using?


I think? I loaded a image taken with the setup (image scale) I see blue area.

I’m now restricted to that size when I draw the red box? Do I then set my rotation and crop for the red box? (is blue just for reference)?


thanks for the heads up - I think I got it. Very cool.


Blue = Reference Image that you provided
Red = FOV of your setup (based on your CCD dimensions and arcseconds/pixel that you provided SGP)

There are some good videos on youtube that explain using the Framing And Mosaic Wizard. Also one on our support page as well.

Couple things to comment on about rotators while you’re here. The angle in SGP is the Sky Angle. When you solve and sync with a rotator connected, SGP will compute an offset for the angle the rotator is stating and convert this to Sky Angle (as this is what actually matters for imaging). The angle that the rotator outputs is generally not useful for imaging purposes, but (sadly) there is no way for SGP to calibrate this like there is to sync a Telescope or set the position of a focuser. So we keep the offset internally, and it requires a sync to make this happen. However if you’re using auto center then this just happens and you don’t need to care. Just know that if your focuser has an angle readout that the angle the focuser reports and what you see in SGP will likely not be the same thing because of the info above.



thanks - I don’t know why I never looked at that before. How cool. I called up 2 dozen targets I want to get to and picks my framing and scope required. I sent a few 4 up mosaics as well. I did M80 and 81 as a “pair” of frames. It’s really slick. I set my 152mm at .64 scale and my 80mm as 2.02 image scale and seemed to work well.

I love being able to load in a wide field and pic the frame/target areas (details) I find most interesting.

Yes I suspect it slews then centers with the same rotation night after night to align frames over several nights and filters. Before I knew this I was shooting a 10 min sub of the target just to center and rotate. This is a great time saver. (10 min !? was required to see any nebulousity of the elephant trunk with 3nm ha. Really working exposure with my setup (F8) nb 3mn - is about 15 min at least per sub.

OH - I thought I had asked - after a pier flip ? SGP will automatically flip the sub? or is there an option I have to set? I suspect if it see’s a rotator it will use it to keep subs in line. That will be awesome.

(before flip it plate solves) so after a flip it centers/solves again… I suspect this will flip the rotator?

OH while you’re here - I have a REQUEST should be easy. Could you add a “SLAVE” dome toggle on the observatory dock? I do have it slave at seq start. But I often want it slaved before I start. Every time I do I have to call up control panel, click other and click Slave. It would be great to see it there in front of me in the dock all the time. As well this would allow me to see when it unslaves… (sometimes I’ll abort, restart and when I abort it thinks seq is done and will unslave. It would be nice to see status all the time on the dock.


That depends on your target settings for the rotator. Personally I use the ±180 option so my rotator doesn’t move during a flip and is taking an “upside down” image compared with the other side of the pier. If you want to attempt to use the same guide star then you should use the “Always” option.

Sure, I’m honestly not sure why it wasn’t like that in the first place. Will be out in the next 3.0 release.



Still test driving the rotator. Last night I had some confusion. The rotator didn’t seem to repond to SGP. Or SGP wasn’t sending the command.
When does the rotator get sent it’s “rot angle?” during slew to or center?
the reason I ask is I can slew to “test” during day, where center will need stars and
plate solving. (I’d like to test any ideas how to do that during the day?)
ODDLY last night - I loaded a previous frame from previous night.
I plate solved my image. (it should pull Ra Dec and angle yes?)
I said “yes use this as target reference”.
I shot a sub and it was not even close to proper/same rotation?

any ideas? so I’m trying to test it today.


I’m trying again tonight. Rotator acts weird. Or SGP not sure what. I was finding the rotator wasn’t going where it should. (in SGP) At one point I noticed the rotator graphic/driver and SGP said they were at different locations.
I parked it at 0 and did a manual sync in SGP of the rotator to 0.
BOTH were aligned. I told it to slew and then center… and (it is shooting subs) but the rotation looks off from previous subs and SGP current position says 89.60 while the Pyxis commander now says 174.9.
Not even close. (which is correct?) IT’s currently shooting subs - but looking at the target settings for this target is says “checked” rotate camera to 168.4 ± 180

So target = 168. (pyxis commander shows 174.9 and SGP sahos position at 89.60
Guiding sometimes goes wild, I then need to re calibrate after rotating. (do you know where PHD2 pulls it’s angle from?) like will it be using SGP’s or the Pyxis commander heading?

Even with both reading differently - guiding is fine right now. But the subs aren’t how I roated them in framing wizard. ???

It’s new to me, could I be doing something wrong?

Actually It appeared rotated, I clicked the image rotation icon and now the alignment seems about right. But get this. My subs are shooting horizontally and the matching framing wizard image is vertically framed?
scratching my head over this one.


Just wondering. When I first started using the Pyxis rotator with SGP and trying to center and rotate on my target, the rotator would never end up in the currect position. It was like it was going in the opposite directions and if it did finally stop in the requested position it was just by luck. What I found is that in the Pyxis rotator ASCOM driver, the default setting is set for “reverse direction” once I unchecked that the rotator worked perfectly with SGP.

I’m just wondering if that might be what is happening with your setup?



Jeff at Optec just replied to me. Said for me not to use the Pysis commander and sgp. Said to use SGP only. Something to do with ASCOM not updating two connections. I run the commander (as well) because I like seeing graphically where it’s pointing). I’ll try tonight with SGP only.
I’ll verify reverse option. (it seems to rotate correctly) But I have a refractor and I can see where this may be a problem with scopes that have multiple relfections. (mirrors).
thanks for the response!


Exactly what I was warning you about here:

Neither are wrong. SGP is sky angle. Rotator is something else that it uses internally.

If I were to make a wild guess I’d say that your Height and Width of your camera are swapped in the SGP camera settings.