FastRotation error

[Corries]

Can anyone please help?

Recently, when I used the FastRotation tool I came up with the following error:

The image contains an astrometric solution that will be deleted by the geometric transformation.

This side effect could be irreversible.  Proceed?

Can anyone explain what this error means and what are the potential consequences?

Many thanks, Terry.

[chris.bailey]

Terry

This suggests the image has at some point in the process been plate solved so contains WCS information in the fits header. Photometric Colour Calibration?

Carrying out any sort of geometric operations on the image (crop, rotate) makes the WCS information invalid so it is deleted.

It is harmless but if you need to have the WCS information back again you will need to run the ImageSolver script on the cropped/rotated image to put it back again.

Chris

[Corries]

Hi Chris,

Thanks for the reply.  However, I have never used a plate solving process.  It must be one of life's great mysteries. 

I carried on with my processing and it didn't affect anything so I'll pretend it didn't happen and hope it never occurs again.

Terry.

[pfile]

if it was a single frame, it's possible that your capture software had inserted an astrometric solution into the fits header either by copying the mount coordinates to the image, or by platesolving it at the time of capture.

rob

[Corries]

Hi Rob,

Thanks for the reply.  I use Sequence Generator Pro for my camera control and data acquisition.  Is it possible that this software is inserting this type of information into the file header?

Many thanks, Terry.

[pfile]

i think it's likely that SGP will write this info to the fits header. it most definitely does if you are using PS2 or Astrometry.net to center your targets. since it is connected to the mount, even in the absence of plate solving it could still be writing the reported mount coordinates to the fits header, but since i always use plate solving i'm not sure if it does this.

rob

[Corries]

Thanks, Rob, your explanations have been a great help.

Terry.