I thought you might like to see this image from Herschel, which I got from the ESA website. The Spitzer/MIPS and the Herschel/PACS images of M51 at 160 µm are shown above. The advantage of the larger size of the Herschel telescope is clearly reflected in the much higher resolution of the image: Herschel reveals structures that cannot be discerned in the Spitzer image.
By golly, it seems to work!
In the Dark 