बृहत्संहिता (आचार्य वराहमिहिर - स्थापत्य, खगोल, मौसम व जल विज्ञान)

10 बृहत्संहितायाम् [Adh. II. 11-13 ११. प्रत्येकग्रहभ्रमणयोजनकक्षाप्रमाणप्रतिविषययोजनपरि- च्छेदकुशलः । 11. He should in the case of every planet be able to calculate its distance (in Yojana) from the Earth, the length of its orbit, etc. १२. भूभगणभ्रमणसंस्थानाद्यक्षावलम्बकाहर्व्यासचरदलकाल- राश्युदयच्छायानाडीकरणप्रभृतिषु क्षेत्रकालकरणेष्वभिज्ञः । 12. He should be familiar with the Earth's rotation (in its own axis) round the Sun and also with its revolution in the stellar firmament, its shape (संस्थान) and the like, the latitude (of a place) and its complement, the difference in the lengths of the day and night, the Chara Khandas of a place, the rising periods of the several signs at any place, the methods of conversion from shadow to time and time to shadow, to find the exact period—elapsed ghatikas since Sun-rise or Sun-set—at any required time from the position of the Sun or from the Lagna as the case may be. For Charakhandas, see Sripatipaddhati PP-157-160. १३. नानाचोद्यप्रश्नभेदोपलब्धिजनितवाक्सारो निकषसन्तापा- भिनिवेशैः कनकस्येवाधिकतरममलीकृतस्य शास्त्रस्य वक्ता तन्त्रज्ञो भवति । 13. He is a true astrologer who is able to under- stand the objections and points of differences and meet them in clear and convincing language thus proving the truth of the science in its pristine purity in the same way as separating pure gold by bringing it under the touch-stone, fire, hammer, etc., and enabling it to retain its pure value.