  We determine the expected signal in various observational bands of Supernovae
Ia progenitors just before the explosion by assuming the rotating Double
Degenerate scenario. Our results are valid also for all the evolutionary
scenarios invoking rotation as the driving mechanism of the accretion process
as well as the evolution up to the explosion. We find that the observational
properties depend mainly on the mass of the exploding object, even if the
angular momentum evolution after the end of the mass accretion phase and before
the onset of C-burning plays a non-negligible role. Just before the explosion
the magnitude M_V ranges between 9 and 11 mag, while the colour (F225W-F555W)
is about -1.64 mag. The photometric properties remain constant for a few
decades before the explosion. During the last few months the luminosity
decreases very rapidly. The corresponding decline in the optical bands varies
from few hundredths up to one magnitude, the exact value depending on both the
WD total mass and the braking efficiency at the end of the mass transfer. This
feature is related to the exponentially increasing energy production which
drives the formation of a convective core rapidly extending over a large part
of the exploding object. Also a drop in the angular velocity occurs. We find
that observations in the soft X band (0.5 -2 keV) may be used to check if the
SNe Ia progenitors evolution up to explosion is driven by rotation and, hence,
to discriminate among different progenitor scenarios.
