M51 Herschel image at 160, 100 and 70 microns

Far-infrared image of M 51, the ‘whirlpool galaxy’ at three different wavelengths (160, 100 and 70 microns) , taken by the Herschel Photoconductor Array Camera and Spectrometer, PACS.

These images clearly demonstrate that the shorter the wavelength, the sharper the image — this is a very important message about the quality of Herschel’s optics, since PACS observes at Herschel’s shortest wavelengths.