Hmm. If I recall correctly, in the Philosophers of Nature the planetary day begins with sundown of the day before. Also, in the LPN, you would have 24 hours, but the hours would be determined by looking at the actual length of time between Sunrise and Sunset, divided by twelve, for the length of the hours of the day, and from sunset to sunrise, to determine the hours of the night. Still 24 hours, but the lengths of the day and the lengths of the hours would vary.