Last modified: 12 December 2023

Why do I get an error message that the size of the PSF image or Exposure map does not match the infile?

# wrecon (CIAO): ERROR: psf image size (3874, 3988) does not match input image size (8192, 8192) 

This happens when users supply wavdetect the event file as input, rather than binning the event file into an image first.

unix% pset wavdetect infile=acis_evt.fits

wavdetect opens the infile as an image. When users supply an event file, the CXC datamodel bins the event file on the X,Y columns into an image: binned by 1 and covering the entire ranges of the columns (ACIS is 8192x8192 pixels). All events are included (ie all energies).

Users should supply wavdetect an image, filtered on the desired energy band and binned to match the exposure map and and PSF map. The fluximage script is used to automate the image and exposure map creation; for purposes of source detection, users will likely want to set the parameter binsize=1 (or maybe =2 for HRC).