Short answers, pulled from the story.
The Surya Siddhanta is a Sanskrit treatise on Indian astronomy that became the most influential astronomical text in Indian history. Scholars date the surviving version of this work to somewhere between the end of the 4th century and the 9th century, with a significant revision likely occurring around 800 CE.
The Surya Siddhanta calculates the Earth's axial tilt to be 23.975 degrees, or 23 degrees 58 minutes 30.65 seconds, which is approximated to 24 degrees. This calculation uses a radius of 3438 and a sine of 1397 for the greatest declination without relying on the modern concept of decimal fractions.
The Surya Siddhanta calculates the Sun's diameter as 6,500 Yojana and the Moon's diameter as 480 Yojana. These measurements use a unit of measurement called the Yojana, which is estimated to be between 8 and 15 kilometers.
The Surya Siddhanta was translated into Arabic during the later half of the 8th century under the reign of Abbasid caliph Al-Mansur. This translation served as one of the two Sanskrit books translated into Arabic and had a considerable influence on Islamic scholarship.
Commentaries on the Surya Siddhanta include the Surya-siddhanta-tika by Mallikarjuna Suri in 1178 and the Surya-siddhanta-bhashya by Chandeshvara in 1185. Another commentary, the Vasanarnava, was written by Maharajadhiraja Madana-pala of the Taka family around 1375 to 1400.