Get a timezone aware datetime with the system timezone in Python

How can I get a datetime object that is timezone aware and is in system's timezone?

What I'm trying to do i开发者_开发知识库s to get unix time of the 23:59 of the current day.

For example, if I do

int(time.mktime(
  datetime.datetime.now(pytz.timezone("Europe/Moscow"))
    .replace(hour=23, minute=59, second=59)
    .timetuple()
))

I get 1314305999; but when I do $ date -d '@1314305999' in console, I get Fri Aug 26 00:59:59 MSD 2011, which is 1 hour off (DST, perhaps), even though I have Europe/Moscow in /etc/timezone (and the same problem arises if I use such timestamp in PostgreSQL).

And specifying a precise timezone is not really preferable.