vs. 14] VIMARDARDHAS 67 A rule for finding the sparse- and moksa- vimardardhas: 14. The square root of the difference between the squares of the Moon's latitude and half the difference between (the diameters of) the eclipsed and eclipsing bodies leads, as before, to the determination of the (nearest approximation in) riadis of the (spar'sa-vimardardha as also of themoksa~) vimardardha. 1 The term vimardardha means "half the duration of totality (of an eclipse)"* and denotes, in the case of a lunar eclipse, the interval between the times of immersion (of the Moon into the shadow) and opposition (of the Sun and Moon), or between the times of opposition (of the Sun and Moon) and emersion (of the Moon out of the shadow). The interval between the times of immersion and opposition is called the spar'sa-vimardardha; and the interval between the times of opposition and emersion is called the moksa-vimardardha. The method for finding the sparsa- and moksa- vimardardhas, given above, is similar to that for rinding the sparsa- and moksa- sthityardhas, stated in stanzas 10-12 above. The difference is that in place of the sum of the semi-diameters of the Moon and the shadow use is made in the present case of their differ- ence. The remainder of this chapter deals with the graphical representation of an eclipse. This requires the knowledge of valana, i.e., the deflection of the ecliptic from the prime vertical on the horizon of the eclipsed body (i.e., on the great circle having the eclipsed body at either of its poles). For the con- venience of calculation, this valana is broken up into two components called' the aksa-valana and the ayana-valana. The former is the deflection of the equa- tor from the prime vertical on the horizon of the eclipsed body, whereas the latter is the deflection of the ecliptic from the equator on the horizon of the eclipsed body. Thus if A, B, G be the points where the prime vertical, the equator, and the ecliptic intersect the horizon of the eclipsed body towards the east of the eclipsed body, then the arc AB denotes the aksa-valana, the arc BG denotes the ayana-valana, and the arc AC denotes the valana. « Cf. MBh, v. 76(H).
