  A 180 micron map and strip maps at 120 and 180 microns were obtained for the
edge-on starburst galaxy NGC 253 with ISOPHOT, the photometer on board the
Infrared Space Observatory. We compare these observations with those obtained
by IRAS at 60 micron and 100 micron and derive the far--infrared spectral
energy distribution at different locations in the galaxy. There is evidence for
the presence of cold dust (T < 20 K) both in the nucleus and in the disk.
Extended emission dominated by cold dust is detected up to 15 arcmin (~ 10 kpc)
along the major and minor axis; its spatial distribution is similar to that
seen in the IRAS and ROSAT PSPC images. The emission along the minor axis is
probably related to large-scale outflows of gas (superwinds) which originate in
the nuclear starburst and maybe to star formation in the halo. The radial
dependence of the dust temperature along the major axis is found using a
radiative transfer code: we show that the dust scale length in the disk is ~
40% larger than that of stars.
