A3. SN 1990N As they did for SN 1998aq, Rie99b transformed eight unfiltered
additional SN 1990N points to the V band. Of the 0.13 mag error they assigned to
those points, 0.05 mag was treated in the AQUAA fit as a point-to-point error.
Again, as for SN 1998aq, the transformed unfiltered points overlap well with two
filtered V measurements, so their zero point was left as a free parameter in the
AQUAA fit. Again, it is in excellent agreement with the Rie99b value. Gaps in
observation of ~8, ~7, and ~6 days occur between t_Bmax_-7 and _Bmax_ + 22 days.
The AQUAA fit became more robust when the stretch-corrected B and V spline knot
phases were fixed to the values fitted for SN 2001el. The quoted uncertainties
include an allowance for the effect of applying this extra constraint.
Images in F218W, F300W, F439W, and F547M of NGC 4639 are available.
Unfortunately, the deeper and more numerous Sandage et al. Cepheid
project images of this galaxy (Saha et al. 1997) do not contain the SN
site, because of the site's proximity to a very bright foreground star.
However, from the images we obtained, using the absolute SN position
from the Sternberg SN catalog, we find that the SN occurred near the
edge of the galaxy along an outer spiral arm. The images in each band
are not deep enough to resolve any individual bright stars or clusters
within the 1.5" radius error circle nor for us to measure the colors of