Chapter 6: Projection of eclipses

6.1 · descriptive (nothing to compute)

why a projection is needed

1. na chedyakam ṛte yasmād bhedā grahaṇayoh sphuṭāh/
jñāyante tat pravakṣyāmi chedyakajñānam uttamam//

6.2-11 · computed

the circles; contact and separation by deflection and latitude; the middle; the eclipsing body there

2. susādhitāyām avanau binduṃ kṛtvā tato likhet/
saptavargāṅgulenādau maṇḍalaṃ valanāśritam//

3. grāhyagrāhakayogārdhasammitena dvitīyakam/
maṇḍalaṃ tat samāsākhyaṃ grāhyārdhena tṛtīyakam//

4. yāmyottarāprācyaparāsādhanaṃ pūrvavad diśām/
prāg indor grahaṇaṃ paścān mokṣo +arkasya viparyayāt//

5. yathādiśaṃ prāgrahaṇaṃ valanaṃ himadīdhiteh/
maukṣikaṃ tu viparyastaṃ viparītam idaṃ raveh//

6. valanāgrān nayen madhyaṃ sūtraṃ yady atra saṃspṛśet/
tatsamāse tato deyau vikṣepau grāsamaukṣikau//

7. vikṣepāgrāt punah sūtraṃ madhyabinduṃ praveśayet/
tadgrāhyabindusaṃsparśād grāsamokṣau vinirdiśet//

8. nityaśo +arkasya vikṣepāh parilekhe yathādiśam/
viparītāh śaśāṅkasya tadvaśād atha madhyamam//

9. valanaṃ prāṅmukhaṃ deyaṃ tadvikṣepaikatā yadi/
bhede paścān mukhaṃ deyam indor bhānor viparyayāt//

10. valanāgrāt punah sūtraṃ madhyabinduṃ praveśayet/
madhyasūtreṇa vikṣepaṃ valanābhimukhaṃ nayet//

11. vikṣepāgrāl likhed vṛttaṃ grāhakārdhena tena yat/
grāhyavṛttaṃ samākrāntaṃ tadgrastaṃ tamasā bhavet//

Computed by: projectEclipse

6.12 · descriptive (nothing to compute)

directions reversed on the ground between the hemispheres (a convention of drawing)

12. chedyakaṃ likhatā bhūmau phalake vā vipaścitā/
viparyayo diśāṃ kāryah pūrvāparakapālayoh//

6.13 · computed

how much of the Moon or the Sun eclipsed is visible

13. svacchatvād dvādaśāṃśo +api grastaś candrasya dṛśyate/
liptātrayam api grastaṃ tīkṣṇatvān na vivasvatah//

Computed by: eclipseVisible

6.14-22 · computed

the path of the eclipsing body; obscuration at any time; immersion and emergence

14. svasaṃjñitās trayah kāryā vikṣepāgreṣu bindavah/
tatra prāṅmadhyayor madhye tathā maukṣikamadhyayoh//

15. likhen matsyau tayor madhyān mukhapucchavinihsṛtam/
prasārya sūtradvitayaṃ tayor yatra yutir bhavet//

16. tatra sūtreṇa vilikhec cāpaṃ bindutrayaspṛśā/
sa panthā grāhakasyoktā yenāsau samprayāsyati//

17. grāhyagrāhakayogārdhāt projjhyeṣṭagrāsam āgatam/
avaśiṣṭāṅgulasamāṃ śalākāṃ madhyabindutah//

18. tayor mārgonmukhīṃ dadyād grāsatah prāggrahāśritām/
vimuñcato mokṣadiśi grāhakādhvānam eva sā//

19. spṛśed yatra tato vṛttaṃ grāhakārdhena saṃlikhet/
tena grāhyaṃ yadākrāntaṃ tat tamograstam ādiśet//

20. mānāntarārdhena mitāṃ śalākāṃ grāsadiṅmukhīm/
nimīlanākhyāṃ dadyāt sā tanmārge yatra saṃspṛśet//

21. tato grāhakakhaṇḍena prāgvan maṇḍalam ālikhet/
tadgrāhyamaṇḍalayutir yatra tatra nimīlanam//

22. evam unmīlane mokṣadiṅmukhīṃ samprasārayet/
vilikhen maṇḍalaṃ prāgvad unmīlanam athoktavat//

Computed by: projectEclipseshadowPathCircle

6.23 · computed

the colour of the obscured part

23. ardhād ūne sadhūṃraṃ syāt kṛṣṇam ardhādhikaṃ bhavet/
vimuñcatah kṛṣṇatāṃraṃ kapilaṃ sakalagrahe//

Computed by: eclipseColour

6.24 · descriptive (nothing to compute)

this teaching is given to a tried pupil

24. rahasyam etad devānāṃ na deyaṃ yasya kasyacit/
suparīkṣitaśiṣyāya deyaṃ vatsaravāsine// [grahayuti]