IMAGE CONSTRUCTION FROM THE IRAS SURVEY

IRAS survery data can be used successfully to produce images of extended objects. The major difficulties, viz. non-uniform sampling, different response functions for each detector, and varying signal-to-noise levels for each detector for each scan, have been resolved. The results of three different image construction techniques are compared: co-addition, constrained least-squares, and maximum entropy. The maximum entropy result is superior. We present an image of the galaxy M51 with an average spatial resolution of 45 arc seconds, using 60-mu-m survey data. This exceeds the telescope diffraction limit of about 1 minute of arc at this wavelength.