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To Resample Calibration Images

The ROSAT PSPC exposure and background maps are 128$\times$128 images (60 $^{\prime\prime}$ pixels) linearly replicated to yield 512$\times$512 arrays (15 $^{\prime\prime}$ pixels). [NB: The HRI background map is also $512\times 512$, but with 8 $^{\prime\prime}$ pixels.] The user can re-sample these maps using IRAF tasks as follows:

  cl> images
  im> magnify rp110590_mex rp110590_mex_demag dx=4 dy=4 inter=linear     # yields a 
                                      # 128*128 exposure map, i.e., true resolution 

  im> magnify rp110590_mex_demag rp110590_mex_15 4 4 inter=spline3       # yields a 
                                                                 # 512*512 map with 
                                                    # 15'' pixels generated using a 
                                                   # 3rd order spline interpolation

The user can apply different interpolation functions to obtain the optimum result. Please note that the size of the final image may not be exactly 512*512 due to edge effects of the binning (type help magnify for more information). skypix can be used to check the sky coordinates against the original image.