vss. 19-20 ] Cara correction 21 for the local equatorial place) provided the Sun is in the northern hemisphere (i.e., to the north of the equator) and added if the Sun is in the southern (hemisphere). In the case of sunset, (the law of correction is) the reverse. In the case of midday or midnight, this (correction) should not be performed. 1 The asu is a unit of sidereal time equivalent to 1/21600 of a Sidereal day. The Sun's ascensional difference measured in asus denotes the time-interval, in asus, between the Sun's rising or setting at the local and local equatorial places. The above correction for the Sun's ascensional difference, therefore, makes allowance for the difference between the times of Sun's rising or setting at the local and local equatorial places. The general formula for the above correction is; Correction for the Sun's ascensional difference {cara correction) _ Sun's asc. diff. in asu sX planet's true daily motion 21600 minutes of arc. When the Sun is in the northern hemisphere, sunrise at the local place occurs earlier than at the local equatorial place, and sunset at the local place occurs later than at the local equatorial place. When the Sun is in the southern hemisphere, it is just the contrary. Hence the law of addition and subtraction of the correction. Since midday or midnight occurs simultaneously at the local and local equatorial places, therefore there is no need of such a correction at that time. When the above correction has been applied to the Sun's true longitude for true sunrise at the local equatorial place, we get the Sun's true longitude for true sunrise at the local place. This is called the Sun's true longitude. We thus see that, in the case of the Sun, to obtain the true longitude for true sunrise at the local place we have to apply to the mean longitude for mean sunrise at Lanka the following four corrections in their respective order: (1) the longitude correction, (2) the bhujaphala correction (i.e., the equation of the centre), (3) the bhujantara correction (i.e., the correction for the equation of ^^^^ time due to the Sun's equation of the centre), 1 Gf. MBh, iv. 26-27(i).
