पृष्ठम्:महाभास्करीयम्.djvu/२५८

173 PROJECTION OF ECLIPSES The next twenty stanzas ralate to the projection (i.e., graphical representation) of an eclipse. A method for ascertaining the centre of the eclipsing body for the times of the first and last contacts (called the sparsa-bindu and the mokşa-bindu respectively): 48-53. By means of a pair of compasses, whose smooth and large body is graduated with angulas and subdivisions there- of and which is embellished by the pointed end of a smoothened chalk-stick placed into its mouth, construct on the ground a circle with half the measure, in angulas, of the eclipsed body as radius, and another (concentric circle) with half the sum of the diameters of the eclipsed and eclipsing bodies as radius. (Through the common centre) then draw the east-west line and, with the help of a fish-figure, the north-south line. From the centre then lay off the valana (for the first or last contact) to- wards the north or south (according to its direction); draw a fish-figure there; and (through its head and tail) carefully¹ draw a line to meet the outer circle. At the meeting point of the outer circle and that line set a point. (This is the centre of the eclipsing body for the time of the first or last contact). From that point stretch out a line to reach the centre. Where this line is seen to intersect the circumference of the eclipsed body, lies the point of contact or separation of the Sun's disc. One minute of arc should be taken as equivalent to one half of an angula or as it appears in the sky. A method for determining the centre of the eclipsing body for the middle of the (solar) eclipse (called the madhya- bindu): 54-57. The valana for the middle of the eclipse is taken ¹ The word "carefully" indicates that when the valana corresponds to the first contact, the line should be drawn towards the west or east according as the eclipse is solar or lunar; but when the valana corresponds to the last contact, the line should be drawn in the contrary direction.