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I have a question about using imshift. I found that imshift cuts off the
images shifted out of the original boundary.e.g. original image is 1000x1000 pixels
when imshift it by [200,300], the output image is still 1000x1000, with the
pixel positions shifted, but only the original 800x700 image pixels are saved in the
output. The rest is lost because they are outside the 1000x1000 boundary.
Is there a way to save the full image when doing the imshift? So in this
example the output should be 1200x1300 in size.Thank you!

Ping,In the simple example you gave I'd just use ARTDATA.MKPATTERN to create a blank larger image of the desired size and then IMCOPY the image into the appropriate image section of the output image. Note this only works for integer shifts, most mosaicing applications will require fractional shifts and I'm not sure why you'd need the blank area, but also have a look at the various combine tasks (e.g. IMCOMBINE, MSCCOMBINE, etc). Hope this helps.Cheers,
-Mike

Hi Mike,Thanks for your help. Integer shift should be good enough.
The reason I want to make the imshift is that I want to make the same star have the same pixel position in different Mosaic images. So I can do the photometry using one star list for all the images. Can you treat problem like this without making the imshift?Thank you!Ping

Since you already know the shift you're after, the LINTRAN task can apply that to a list of positions for you to correct for each image.Another solution: Since the ra/dec will be the same, look at WCSCTRAN to convert that 'world' position to a 'logical' one for the image, i.e. compute the (x,y) for the star given the (ra,dec) using the image wcs.-Mike

Hi Mike,I found that GEOTRAN does the thing I want. Just set xmax and ymax equal to the
original size plus shift.Cheers,Ping