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

Chapter IV
Brahmagupta’s Originality
in the Khaṇḍakhādyaka
Sengupta in his Indroduction to the Commentary of the
Khaṇḍakhādyaka has discussed this point. We shall reproduce
here some of the points mentioned by him.
Brahmagupta’s Khaṇḍakhādyaka
(i) Brahmagupta does not accept the system of Āryabhaṭa
but has simplified it in the Khaṇḍakhādyaka proper ; and here
he has given the system which he thinks to be correct.
Uttar Khaṇḍa Khādyaka
(ii) In the Uttara-Khaṇḍakhādyaka, he has further correc-
ted some of his results, given earlier in the Khaṇḍakhādyaka
proper. In the proper Khaṇḍakhādyaka, Brahmagupta assignes
to the longitude of the Sun's apogee the value 80º, whereas in
the Uttara text he corrects it to 77º (UKK. 4) :
As the process of finding the apparent places of planets
as given by Āryabhaṭa does not make them agree with
observation, I shall, therefore, speak of this process.
Of the Sun the apogee is at two signs and seventeen
degrees (2 signs 17º=60 plus 17 degrees=77º).¹
Compare this with the value given in the Khaṇḍakhādyaka
proper (I.13)² :
The longitude of the Sun's apogee is 80º [KK.I,13] (The
Sun's apogee is 80º or two signs plus 20 degrees) inocco means

1. न स्फुटमार्य्यभटोक्तं स्पष्टीकरणं यतस्ततो वक्ष्ये ।
   भानुमतो मन्दोच्चं राशिद्वयमंशकाश्च सप्तदश ॥ UKK. IX 4
2. भागाशीतिरितिनोच्चं शशिनः पादोनकृत शरकृतोनाद् ।
   भगणादि द्विस्त्रिर्दैर्वसुशुनव यम नव गुणैः सकलम् ॥ KK. I, 13