Is Lagna dependent on Day duration and Night Duration of the country ? For example, if the day duration in Summers is say 16 hrs and night duration is 8 hrs. Similarly in winters the day and night duration gets reversed. If the day or night duration is short, then the lagna duration is also short and vice versa.
In Telugu panchanga, the Lagna tables assume sun rise at 06:00 AM and Sun Set at 06:00: PM. Accordingly, day wise lagna duration for the year are given.