Confusion in the infrared: Spitzer and beyond
  We use the source counts measured with the Multiband Imaging Photometer for Spitzer (MIPS) at 24, 70, and 160 microns to determine the 5-sigma confusion limits due to extragalactic sources: 56 micro-Jy, 3.2 and 40 mJy at 24, 70 and 160 microns, respectively. We also make predictions for confusion limits for a number of proposed far infrared missions of larger aperture (3.5 to 10m diameter). 
H. Dole, G. H. Rieke, G. Lagache, J-L. Puget, A. Alonso-Herrero, L.   Bai, M. Blaylock, E. Egami, C. W. Engelbracht, K. D. G...