Example of a “mixed” source. SPIRE 500 μm (left) and PACS 160 (right) images of Pox186 and a contaminating background source. The sources are 20′′ apart, and are well separated at 160 μm, but are completely blended at SPIRE 500 μm resolution. Pox 186 corresponds to the bottom cross, whereas the contaminating background source is the X. The SPIRE 500 μm (FWHM = 36.3′′) and the PACS 160 μm (FWHM = 11.3′′) beams are indicated as white circles on the bottom right of the images.