Emexes,
It doesen't have to be very accurate. Latitude change can be avoided and as you rightly pointed out, applicable to lower and mid latitutes only, due inaccurate dlat and dlong measuring capabilities. Thanks.
Erel
As UI has only one date entry,ie date of departure, then it can so happen that End time goes into next day. Therefore, I prefer using ticks for times and in such a case, use dateutils.addperiod to add one day to End time.
I actually found working out day and night time calculations a little complicated for me, so asking here..
Rgds..