For the MIPS SED mode, the SIRTF manual gives a point source sensitivity level of 15 to 20 mJy over the wavelength range 55 to 96 microns. This figure translates this estimate to surface brightness sensitivity.

The expected SED over this wavelength range along the NGC 6946 radial cut is given here, and the corresponding signal-to-noise ratio profiles are given in this figure.

The field of view for the MIPS SED mode is 3.8x0.32 (arcminutes).