Śaṅkaranārāyaṇa

Observatory

• The vivarana mentions a royal observatory at Mahodayapura.
• There are references to an instrument called "Rashi Chakra" marked by a "Yanthra Valaya" in the vivarana. This instrument might be the same as the Gola Yanthra/Chakra Yanthra mentioned by famous polymath Aryabhata. The Chakra Yanthra was developed further and called Phalaka Yanthra by Bhaskara I.
• At the directions of Sankara Narayana, in every 'katikai', bells were sounded at different important centres of Mahodayapura to announce correct time.

  Mathematical contributions

• Laghu Bhaskariya Vivarana covers the standard mathematical methods of Aryabhata I such as the solution of the indeterminate equation by = ax ± c in integers which is then applied to astronomical problems. The Indian method involves using the Euclidean algorithm. It is called kuttakara.
• The most unusual feature of the Laghubhāskarīyavivaraṇa is the use of katapayadi system of numeration as well as the place-value Sanskrit numerals which Laghubhāskarīyavivaraṇa frequently uses.

  Identification of king Ravi Kulasekhara with Sthanu

• The opening verse of Laghu Bhaskariya Vyakha gives an indirect invocation to the lord called "Sthanu".

• Sankara Narayana also mentions that the full name of his king as "Ravi Varma Kulasekhara".
• Laghu Bhaskariya Vivarana was composed in the 25th regnal year of king Kulasekhara.

  Date of ''Laghu Bhaskariya Vivarana''

• "Angartvambara nanda devamanubhir yate dinanam gane"
• * Anga = 6, Rtu = 6, Ambara = 0, Nanda = 9, Veda = 4, and Manu = 14
• * Order - 6609414
• * Reverse Order - 1449066
• Kali Date - 3967 years and 86 days = 25 Mithuna, Kollam Era 41 = 870 AD
• "Evam Sakabdah punariha candra randhramuni sankhyaya asambhiravagatah"
• * Candra = 1, Randhra = 9, and Muni = 7
• * Order - 197
• * Reverse Order - 791 = 870 AD

• Meeting of Guru and Sauri in Capa = 25th regnal year of the king = 870 AD