  We present sub-millimetre images of the spiral galaxy NGC 6946 at 450 and 850
um. The observations have been carried out using the scan/map imaging mode of
the Sub-millimetre Common User Bolometer Array (SCUBA) at the James Clark
Maxwell Telescope (JCMT). The comparison with a 12CO(2-1) line emission map
from IRAM and with an U-band image, clearly shows that the 850 um emission is
associated with molecular gas and bright star-forming regions, tracing the
spiral arms. We place an upper limit of 0.7 for the V-band optical depth of
dust associated with a diffuse atomic component.
