Short answers, pulled from the story.
The Surya Siddhanta is a Sanskrit treatise on Indian astronomy attributed to Lāṭadeva, a student of Aryabhatta I. It comprises fourteen chapters and is dated to somewhere between the end of the 4th and the 9th centuries CE, with a probable major revision around 800 CE.
The Surya Siddhanta's sidereal period for Mercury is 87 days 23 hours 16 minutes 22.3 seconds, compared to the modern figure of 87 days 23 hours 15 minutes 43.9 seconds. For Venus and Mars the errors are similarly small, within a few minutes. Whitney noted the Moon's revolution is accurate within a second, though the Hindu year runs nearly three and a half minutes long.
During the reign of Abbasid caliph Al-Mansur, the Surya Siddhanta was one of two Sanskrit texts translated into Arabic in the later half of the eighth century. According to Muzaffar Iqbal, this translation and that of Aryabhata were of considerable influence on Islamic geography, astronomy, and related scholarship.
The solar component of the luni-solar Hindu calendar is based on the Surya Siddhanta. According to J. Gordon Melton, both Hindu and Buddhist calendars currently in use across South and Southeast Asia are rooted in this text, though regional adaptations have modified them over centuries.
The text used symbolic substitution to encode numbers within Sanskrit verse. Because numbers lack rhyming synonyms, the authors used words with double meanings; the word for moon, for example, represented the numeral one because there is one moon. This cipher allowed the entire sine table, orbital calculations, and eclipse prediction methods to be expressed in poetic form.
The Surya Siddhanta has attracted at least 26 named commentaries plus 8 anonymous ones, the largest number of commentaries of any Indian astronomical text. The earliest named Sanskrit commentary, the Surya-siddhanta-tika by Mallikarjuna Suri, was written in 1178, and commentaries continued to be produced through at least the late 17th century.