Hindu calendarThe Hindu calendar, (also called Panchanga) (पञ्चाङ्ग) or Panjika is one of various lunisolar calendars that are traditionally used in the Indian subcontinent and Southeast Asia, with further regional variations for social and Hindu religious purposes. They adopt a similar underlying concept for timekeeping based on sidereal year for solar cycle and adjustment of lunar cycles in every three years, but differ in their relative emphasis to moon cycle or the sun cycle and the names of months and when they consider the New Year to start.
Irrational numberIn mathematics, the irrational numbers (from in- prefix assimilated to ir- (negative prefix, privative) + rational) are all the real numbers that are not rational numbers. That is, irrational numbers cannot be expressed as the ratio of two integers. When the ratio of lengths of two line segments is an irrational number, the line segments are also described as being incommensurable, meaning that they share no "measure" in common, that is, there is no length ("the measure"), no matter how short, that could be used to express the lengths of both of the two given segments as integer multiples of itself.
Sine and cosineIn mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is opposite that angle to the length of the longest side of the triangle (the hypotenuse), and the cosine is the ratio of the length of the adjacent leg to that of the hypotenuse. For an angle , the sine and cosine functions are denoted simply as and .
HeliocentrismHeliocentrism (also known as the Heliocentric model) is the astronomical model in which the Earth and planets revolve around the Sun at the center of the universe. Historically, heliocentrism was opposed to geocentrism, which placed the Earth at the center. The notion that the Earth revolves around the Sun had been proposed as early as the third century BC by Aristarchus of Samos, who had been influenced by a concept presented by Philolaus of Croton (c. 470 – 385 BC).
Vedic periodThe Vedic period, or the Vedic age (1500-500 BCE), is the period in the late Bronze Age and early Iron Age of the history of India when the Vedic literature, including the Vedas (1500–900 BCE), was composed in the northern Indian subcontinent, between the end of the urban Indus Valley Civilisation and a second urbanisation, which began in the central Indo-Gangetic Plain 600 BCE. The Vedas are liturgical texts which formed the basis of the influential Brahmanical ideology, which developed in the Kuru Kingdom, a tribal union of several Indo-Aryan tribes.
Earth's rotationEarth's rotation or Earth's spin is the rotation of planet Earth around its own axis, as well as changes in the orientation of the rotation axis in space. Earth rotates eastward, in prograde motion. As viewed from the northern polar star Polaris, Earth turns counterclockwise. The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is the point in the Northern Hemisphere where Earth's axis of rotation meets its surface. This point is distinct from Earth's North Magnetic Pole.
BiharBihar (bᵻˈhɑːr; bɪˈɦaːr) is a state in eastern India. It is the third largest state by population, the 12th largest by area, and the 14th largest by GDP in 2021. Bihar borders Uttar Pradesh to its west, Nepal to the north, the northern part of West Bengal to the east, and with Jharkhand to the south. The Bihar plain is split by the river Ganges, which flows from west to east. On 15 November 2000, southern Bihar was ceded to form the new state of Jharkhand. Only 20% of the population of Bihar lives in urban areas as of 2021.
ZijA zij (zīj) is an Islamic astronomical book that tabulates parameters used for astronomical calculations of the positions of the sun, moon, stars, and planets. The name zij is derived from the Middle Persian term zih or zīg ("cord"). The term is believed to refer to the arrangement of threads in weaving, which was transferred to the arrangement of rows and columns in tabulated data. Some such books were referred to as qānūn, derived from the equivalent Greek word, .
VarāhamihiraVarāhamihira (6th century CE, possibly 505 – 587), also called Varāha or Mihira, was an astrologer-astronomer who lived in Ujjain in present-day Madhya Pradesh, India. Unlike other prominent ancient Indian astronomers, Varāhamihira does not mention his date. However, based on hints in his works, modern scholars date him to the 6th century CE; possibly, he also lived during the last years of the 5th century. In his Pancha-siddhantika, Varāhamihira refers to the year 427 of the Shaka-kala (also Shakendra-kala or Shaka-bhupa-kala).
Āryabhaṭa's sine tableĀryabhata's sine table is a set of twenty-four numbers given in the astronomical treatise Āryabhatiya composed by the fifth century Indian mathematician and astronomer Āryabhata (476–550 CE), for the computation of the half-chords of a certain set of arcs of a circle. The set of numbers appears in verse 12 in Chapter 1 Dasagitika of Aryabhatiya. It is not a table in the modern sense of a mathematical table; that is, it is not a set of numbers arranged into rows and columns.
