ब्राह्मस्फुटसिद्धान्त (ब्रह्मगुप्त - शून्य, कुट्टक, बीजगणित एवं सम्पूर्ण २१ अध्याय सान्वय सटीक)

CONCORDANCE OF WORKING RULES 307
Also MBh. III 24; ŚiDVṛ. I. iii. 27; SiŚe IV. 37
18. Rule for finding the Sun's altitude when the Sun's
ascensional difference is greater than the given time : BrSpSi.
III. 33 :
Also MBh. III 25, LBh. III. 11; ŚiDVṛ. I. iii. 29 SiŚe. IV. 41.
19. Rule for finding the Sun's altitude in the night :
BrSpSi. III. 63.
Also MBh. III. 26; LBh. III. 11; SiŚe. IV. 89.
The Sun's altitude for the night has been called Pātāla
Śaṅku by Brahmagupta (BrSpSi. XV.9)
20. Rule for finding the longitude of the rising point of
the ecliptic with the help of (i) the instantaneous sāyana longi-
tude of the Sun and (ii) the civil time measured since sunrise,
or with the help of (i) the Sun's sāyana longitude at sunrise
and (ii) the sidereal time elapsed since sunrise : BrSpSi III. 18-20.
Also MBh. III. 30-32: LBh. III. 17-19; SūSi. III. 46-48;
ŚiDVṛ. I. iii. 11-12: SiŚe IV. 18-19 (i) : SiŚi I. iii. 2-4.
21. Rule for obtaining the civil time measured since
sunrise with the help of (i) the Sun's instantaneous sāyana longi-
tude and (ii) the sāyana longitude of the rising point of the
ecliptic, or the sidereal time elapsed since sunrise with the help
of (i) the Sun's sāyana longitude at sunrise and (ii) the sāyana
longitude of the rising point of the ecliptic: BrSpSi III. 21-23.
Also SūSi. III.50-51; MBh. III. 34-36; LBh. III. 20;
ŚiDVṛ. I. iii. 13; SiŚe IV. 19 (ii)—22 (i); SiŚi I. iii. 5–7. (i).
22. Rule for determining the R Sines of the Sun's prime
vertical altitude : BrSpSi III. 52.
Also Ārya. IV; MBh. III.37-38; LBh. III. 52.
(An error created by Āryabhaṭa has been criticised by
Brahmagupta.)
23. Construction of the locus of the end of the shadow
of a gnomon : BrSpSi. III. 2-3.
Also MBh. III 52; ŚiDVṛ. I. iii. 3; SiŚe, IV. 5;
24. Rule for finding the Sun's mean anomaly: BrSpSi,
II. 12 (i).