Aharmana is the duration of a day in Hindu astrology. The duration of a day is the difference of time between sunrise and sunset. Ratrimana is the duration of night in 24 hours minus dinamana. Dinamana given in panchangas (almanacs) relates to the true sunrise and sunset and apparent sunrise and sunset. True sunrise means the sun touching the horizon and apparent sunrise or sunset means the visibility of the Sun due to refraction so that the sunrise appears earlier and sunset appears slightly later. The celestial longitude of the Sun, as given in ephemeris, pertains to the center of the sun’s disc while the sunrise and sunset are taken from the upper limb of the Sun. Thus, the true and apparent dinamana differs by four or five minutes at the Tropic of Cancer of nearby. Thus, sunrise and sunset decide dinamana, and as sunrise and sunset depend on geographical latitude of the place and the sun’s declination on the date of observation. The sun’s declination is zero on March