Hello, I have been using SGP for just a few months, looked up and down the manual and videos, but cant solve a problem I encounter with the Mosaic/Framing wizard
In SGP:
I point the telescope to a target
I take a quick frame
I plate solve it using the right mouse click function, and obtain the camera angle (Using the PlateSolve 2.29)
I get a solution, and an angle
Save it as Mono FIT using the right mouse function
Import the FIT in the Framing/Mosaic wizard
Fetch the portion of the sky
…The blue rectangle representing my picture is wrongly rotated
Am I doing something wrong?
What I find is that the angle of rotation inside the FIT Header is ALWAYS 0deg
I assumed that by plate solving, it would be corrected for the one identified in the plating
How to take a frame and pass it to the mosaic for extension/framing with the correct angle?
Seems like you are going backwards. If you use the framing wizard from the start and make the target through that it will put the angle in your target and should save to the image. What camera are you using?
If you just want to make a new sequence with an already existing image, just plate solve as you did but click the checkbox “Use these results as the refrence image for target xyz” this will populate the SGP Target with the exact coordinates and angle needed to match that same image.
To get to that target right click on it and say “center here” (or slew first then center here)
Thanks, I understand that, but I want to do something different
Actually I dont want to rotate the camera (by the way a QHY247C) since I dont have a rotator, and manually rotating the camera is a complication I would like to avoid; I just want to frame my target properly
When I slew to a target, often I dont really see how exactly I am positioned vs such target by taking a few sec frames. Sometime you can determine by looking at bright stars, but is not always possible
The intent is to plate solve the frame and use the framing wizard to see how exactly I am positioned on the target and evaluate the surrounding area based on the frame acquired
I eventually want to shift my position to better frame the target (maybe capturing some bright star immediately near but out of frame)
For instance in the above example, I took the frame, SGP tells me that based on my plate solution and angle of rotation M95 is IN frame… but it isnt
Unfortunately, the blue box that should represent my frame, is incorrectly positioned… like I showed is 90deg rotated, and M95 is outside
If it was giving me the proper framing given my camera rotation (the green box I manually superimposed), I would have shifted the target in order to capture also M95
I believe the reason is the lack of proper angle in the FIT header, since I use an image created by SGP for the framing (tipically a focus/frame image)
The FIT header shows always 0deg, even if the angle is different from zero
Yes, I can do things differently to manually compensate the issue… point is that the FIT header has the wrong rotation angle, which seems a bug to me
All you need to do is determine what your ‘current’ rotation angle is. To do that take an image with how your camera is currently inserted. After you plate solve that image by right clicking it and saying “plate solve” you get that angle.
From then on, use that Angle in your framing wizard for future targets.
As long as you don’t rotate your camera from how it was then you will be fine.
yes, It is a way of going around the issue
However still the FIT header has the wrong angle. Would be good if the header has the proper angle after having plate solved the image
Or otherwise adding a “send to mosaic wizard” to the right-click menu of the image and sending directly coordinate+angle from the image without passing by the save and FIT header
SGP doesn’t actually plate solve your captured images, it saves the angle which is set in your settings and as i can see when you make your target framing & mosaic wizard is set to 0 degrees, this is the reason the fits file has the wrong angle.
When you load a Fits file into framing & mosaic wizard it uses the values saved in the fits file, not the plate solved values.
If you add the correct angle to the settings it will be input automatically later too
Ok… so plate solving and then saving the FIT doesn’t actually save on the FIT header the actually plate solved info
Camera angle is static and defined in settings
Got it. How is phrased in the manual (and I saw on a tutorial video) mislead me in believing that the FIT header is corrected by the plate solving
The manual says “you can use an existing FITS taken with SGP… a blue rectangle will be drawn…”
In this case would be a suggestion for improvement
Instead of a static angle coming from setting… a dynamic angle derived from the plate solving passed to the wizard. Or a field for the initial camera angle available in the wizard that can be populated with the plate solved result vs the static value in the configuration
Anyway, many thanks for the clarification and explanation
I’m not really sure if it saves the info if you plate solve an image, maybe check header for the fits file after it’s saved?
If you do “center on” instead of just “slew to” a target the angle should be saved correct in the fits file, angle in settings seem to also be automatically changed at this time so it should be correct if you do things correctly.
I just did a test by removing most info in the FITS header and then solve it with SGP, SGP does not correct/add info to the FITS header after a plate solve.
