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

II.13 II. VĀSIṢṬHA-SIDDHĀNTA 39
The previous (a), is: lagna = Sun + 36/(12 + shadow − noon-shadow). Therefore, lagna − Sun = 36/
(12 + shadow − noon-shadow). Therefore 36/(lagna − Sun) = 12 + shadow − noon-shadow. There-
fore, shadow = 36/(lagna − Sun) + noon-shadow − 12, where it is to be noted that (lagna − Sun)
is in rāśis. If it is to be expressed in minutes, we have, shadow = 36/(lagna − Sun) × 1800 ÷ 1800

• noon-shadow − 12 = 36 × 1800/(lagna − Sun) in minutes + noon-shadow − 12 = 64800/(lagna
  − Sun) in minutes + noon − shadow − 12, which is (a) here.
  The previous (b) is: lagna = Sun + 6 − 36/(shadow + 12 − noon-shadow). Therefore 36/(shadow
• 12 − noon-shadow) = Sun + 6 − lagna = 6 − (lagna − Sun). Therefore 36/{6 − (lagna − Sun)}
  = shadow + 12 − noon-shadow. Therefore shadow = 36/{6 − (lagna − Sun)} + noon-shadow − 12,
  where (lagna − Sun) is in rāśis. If it is to be expressed in minutes, we have, shadow = 36/6 − { 6 − (lagna
  − Sun) × 1800 ÷ 1800} + noon-shadow − 12 = 36 × 1800/{6 × 1800 − (lagna − Sun) in minutes}
• noon-shadow − 12 = 64,800/{10,800 − (lagna − Sun) in minutes} + noon-shadow − 12, which
  is (b) here.
  The concluding words, Vāsiṣṭha-samāsa-siddhānte, though forming a part of the sentence giving
  the rules of verses 12-13, may be detached from it and taken to refer to the whole chapter II and
  mean ‘All this is given as in the succinct Vāsiṣṭha Siddhānta’.
  The word, nakṣatrādicchedaḥ is found at the conclusion in the manuscripts. Perhaps it is, nakṣatrā-
  dhicchedaḥ, meaning ‘Naksatra section’ and the title is appropriate because this is the chief thing
  given here and other things depend on it.
  Thus in this chapter the true Sun and Moon are given according to the Vāsiṣṭha and also other
  matters depending on them like the nakṣatra, the tithi, day-time shadow and lagna. (The star planets
  i.e. the regular planets, of this Siddhānta will be given in XVIII.)
  TS have professedly not understood verses 1, 5 and 6 and gone wrong in verses 3 (and 8), which
  means they have practically not understood the Siddhānta at all. Thibaut even thinks that verse 1
  may be dealing with the Moon. But this professed ignorance did not prevent him from making the
  unwarranted remark in the Introduction (vide p. XXXVIII)..... “the methods are so crude and so
  completely omit to distinguish between mean and true astronomical quantities, that the Vasistha
  Siddhanta can hardly be included within Scientific Hindu Astronomy.”
  [इति पञ्चसिद्धान्तिकायां वराहमिहिरविरचितायां
  वासिष्ठसिद्धान्ते ग्रहादिगणितं नाम द्वितीयोऽध्यायः ॥]
  A.B. have as Colophon, नक्षत्रादि छेदः; C.D. नक्षत्रादिच्छेदः |
  Thus ends Chapter Two entitled ‘Vāsiṣṭha-Siddhānta: Planetary
  Computations etc.’ in the Pañcasiddhāntikā composed by
  Varāhamihira