पञ्चसिद्धान्तिका (आचार्य वराहमिहिर - सूर्य, रोमक, पौलिश, वासिष्ठ एवं पितामह सिद्धान्त)

XVIII.40 XVIII. VĀSIṢṬHA-PAULIŚA – RISING AND SETTING 343 These verses actually give the true longitudes at the time of rising corresponding to mean lon- gitudes. The mean longitude is obtained as per the previous verse. TS and NP think that, in verses 38b-40, the true motion of Mercury is given, for certain days cer- tain degrees, and so on. They have made some emendments of their own and both of them get the total degrees moved as 360 but as for the number of days TS get 389 while NP get 388. The 389 of TS is the same as the divisor of the previous verse and so they think that corresponding to the remaining days which will be upto 389 these verses give the true śīghra-sphuṭa. But their idea is vague and they are not able to expand it properly. NP think that what is given is an eightfold division of the ecliptic but they are not able to explain anything further. They comment, "The text calls n1 'days' which, in any case, is meaningless". In fact there seems to be no reference to days at all in these verses. अनयोर्विश्लेषांशान् दिवसेभ्यः शोधयेत् स्फुटाभ्यधिके । अधिके.तु (मध्यमेऽंशान्) दद्याच्चारः स्फुटबुधाच्च ॥ ४१ ॥ 41. Deduct from the days the degrees of difference of these two, (i.e., of the mean and true places of Mercury), in case the true place is in excess of the mean place, and add if the mean is in excess of the true. Then the course of true Mercury is as follows. TS and NP have not been able to appreciate the rationale for this operation. TS have not given any rationale. NP think that the correction applied to the days is a mistake and it should be applied to the longitude; and the correction to the days should be applied by dividing the correction (in degrees) by the synodic motion per day. This however is not the correct position. Since this relates to the rising position of Mercury on the true date the Sun will be 12 degrees less than the true Mercury. So the Sun also will have to be corrected by the difference between the true and mean positions of Mercury. Since the motion of the Sun can be taken as one degree per day for small durations, to that extent of the difference the rising date will shift. If the true Sun is in excess, the date will get advanced, and, consequently, the remaining days will get reduced, and vice versa. Obviously the number of days will be equal to the number of degrees. Note on Verses 42-53 These verses give the gati-s of Mercury relating to the twelve signs, Aries to Pisces. In each verse, the first quarter gives the degrees (days) of motion from the rising of the planet to the commence- ment of retrogression, the second quarter for the period of retrogression, the third for the period from the end of retrogression to the setting of the planet and the fourth from setting to its rising. In order to check the accuracy of the figures, they have been calculated by modern methods. The variants, as: चतुरधिके पञ्चशतेन तिरूनं and 41a. A.B. ॰पांशा धिशातिरवं. b. A. शोधये स्फु. C. धिके च. c. A.B. मध्यमे स्या c. A.B. repeat after b, verse 40, with a few d. A.B. दद्याच्चार (B1.2. चारः)