Is there a difference between behaviour of ephem.date(. . .) and ephem.Date(. . .) in PyEphem? As far as I can see, both have the same effect.
The nice thing about python is that you can usually read the source code.
I found my pyephem installed in /usr/lib64/python2.7/site-packages/ephem/
and in there was the comment:
# For backwards compatibility, provide lower-case names for our Date
# and Angle classes, and also allow "Lon" to be spelled "Long".
date = Date
angle = Angle
LongLatCoordinate = LonLatCoordinate
so you are right ephem.date() and ephem.Date() are the same, but Date is preferred.