How do you use plate solve to center your object?


Hey guys,

I have been using SGPro for a while and LOVE it. I was wondering how others use Plate solve and centering to get the perfect framing. I have framed my image in CDC and StarryNights and found the perfect angle I want and position. NOW how do I set up SGP to mimic my screen. I every thing can be done via SGP Rotator, focus and filterwheel. I will give an example of what happen.

I was imaging NGC891 (and BTW i am missing all the little galaxies i was hoping to get) during the first half of the night. At 1:30 i had the scope change objects and do Horsehead. Well Horsehead is perfectly centered however Flame is so close to the edge that it will look so bad once I process it because of dithering and cropping.

Do you use Coords of an object that is to be centered? how do you force the rotator to be at a specific angle ? I have tried to set “On target start, rotate to:” but this seems to mess up when the rotator tries to go past or goto 0 Deg. I use Moonlite focuser.

Any suggestions would be great. I am wasting a great dark window (only two days due to weather) because of this issue.

If some one could explain the how the rotator and solve feature work together that would be awesome. Thanks?


Whenever I plan to image certain DSO, I go to and find the best framed image I look for, then I copy the URL address, paste it in SGP, do a solve of that link and it returns the coordinates of the center of the image.



Awesome thanks I will give it a go.


I will typically (in fact I just did this for tonite’s object) find an image of the object on the web. I try to find one that is a bit wider FOV than I plan to use.

Then I bring up TheSkyX (or similar of your choice). I look at the web image in Photoshop and also the area in TheSky with my instrument’s FOV displayed in the latter. Then I crop the image in PS to match my desired FOV, position, and angle. Finally, I put a crosshairs on the image (using guides in PS) and that tells me exactly where to put the cursor in TheSky for the center of the image. I then copy those coordinates into SGP.

This works especially well for nebulae where you might want specific framing to include some surrounding dark nebula structure and such. Seeing another image that shows this stuff and using that to get ideal framing works well. The image you get from the web does not have to be great, just OK so that it shows the nebulosity. After all, you plan to do better anyway, no? :wink:


In my opinion the best thing you can do is get the Framing and Mosaic Wizard add-on for SGP. It’s so easy to use, you get the exact visual framing you want, the exact angle you want and the wizard fills in the plate solve coordinates for you. This will address your questions about framing an object.

Unfortunately I do not have a rotator so I can’t help there. But if you have “on target start, rotate to:” enabled then the software should move the rotator to whatever angle you tell it to. So if you’re having an issue with your rotator I’m guessing that this is a problem, and not just a misunderstanding of the software.

Please see this post on how to ask for help: