I think we should make sure, that time zones, other time references are used correctly.
We can have time stamps given as UTC, really related to a time zone, local time (without DST), mean solar time, true solar time, ...? This is an everyday problem from my experience, so we should be able to handle all of these formats at least in the future.
For now it could be ok to define, that all times should be given as UTC and leave all time conversion issue to the user.

As pandas has support for Julian dates since 0.14 (this is the pull request). I was thinking about creating a pull request to implement to_solar_time in pandas. However this is not easy to implement and I am not sure, if they accept it. But this way all time conversion would be in pandas an we could implement thinks based on pandas.