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Two Questions
1. When I split a mosaic file, all the headers for the split images have the sane original R.A/Dec from the original mosaic. Is there a way to split mosaic files and have the new individual images have the proper coordinates in the new headers?
2. Is there a way to rotate mosaic and to "flip" the mirror image?
Thanks,
David

Hello David,1a) The model for mosaic WCS is that all pieces from an exposure share a common tangent point. Technically that means CRVALn keywords though in practice this also means any generic RA/DEC keywords. There is no special feature in the software (both acquisition or processing) for using separate RA/DEC for each piece
1b) The split task is intended to be very simple so it doesn't do much to the headers except put something in to allow a simple reverse of split.
1c) You can easily evaluate the WCS to find what you want. Suppose you split foo into foo1, foo2, etc. Then[code:1:86c1c2ff63]
cl> wcsctran STDIN STDOUT foo1 logical world formats="%.2H %.1h"
1024 1024
4:02:23.1 43:24:15.1
[EOF]
[/code:1:86c1c2ff63]You would put in the middle pixel coordinate to get the RA/DEC at the middle.2) There are several ways to alter the orientation. First if you just want it flipped in a display then the display tool (ds9, ximtool) may provide what you want. If you are resampling to a single image using the WCS with mscimage you can set whatever final orientation you want. If you really just want to rotate the pixels then you can use image sections or the rotate task.For the latter there is no mosaic MEF specific tool. You would need to do each extension separately. You can changes the individual pieces but I'm not sure what it would mean to flip the whole exposure. Again it depends on if the final goal is just to display. For display the DETSEC keywords define the tiling in many cases. I think this question is not well defined. Normally you should not need to do this for any processing or analysis reason. It would just be for display and for the final resampled image orientation which I've addressed above.Yours,
Frank Valdes