SundialA sundial is a horological device that tells the time of day (referred to as civil time in modern usage) when direct sunlight shines by the apparent position of the Sun in the sky. In the narrowest sense of the word, it consists of a flat plate (the dial) and a gnomon, which casts a shadow onto the dial. As the Sun appears to move through the sky, the shadow aligns with different hour-lines, which are marked on the dial to indicate the time of day. The style is the time-telling edge of the gnomon, though a single point or nodus may be used.
AstrolabeAn astrolabe (ἀστρολάβος astrolábos; ٱلأَسْطُرلاب al-Asṭurlāb; ستارهیاب Setāreyāb) is an astronomical instrument dating back to ancient times. It serves as a star chart and physical model of visible heavenly bodies. Its various functions also make it an elaborate inclinometer and an analog calculation device capable of working out several kinds of problems in astronomy. In its simplest form it is a metal disc with a pattern of wires, cutouts, and perforations that allows a user to calculate astronomical positions precisely.
Hellenistic periodIn classical antiquity, the Hellenistic period covers the time in Mediterranean history after Classical Greece, between the death of Alexander the Great in 323 BC to the death of Cleopatra VII (30 BC) followed by the emergence of the Roman Empire, as signified by the Battle of Actium in 31 BC and the conquest of Ptolemaic Egypt the following year. The Ancient Greek word Hellas (Ἑλλάς, Hellás) was gradually recognized as the name for Greece, from which the word Hellenistic was derived.
Muslim worldThe terms Muslim world and Islamic world commonly refer to the Islamic community, which is also known as the Ummah. This consists of all those who adhere to the religious beliefs and laws of Islam or to societies in which Islam is practiced. In a modern geopolitical sense, these terms refer to countries in which Islam is widespread, although there are no agreed criteria for inclusion. The term Muslim-majority countries is an alternative often used for the latter sense.
Chinese astronomyAstronomy in China has a long history stretching from the Shang dynasty, being refined over a period of more than 3,000 years. The ancient Chinese people have identified stars from 1300 BCE, as Chinese star names later categorized in the twenty-eight mansions have been found on oracle bones unearthed at Anyang, dating back to the mid-Shang dynasty. The core of the "mansion" (宿 xiù) system also took shape around this period, by the time of King Wu Ding (1250–1192 BCE).
Indian astronomyIndian astronomy refers to astronomy practiced in Indian subcontinent. It has a long history stretching from pre-historic to modern times. Some of the earliest roots of Indian astronomy can be dated to the period of Indus Valley civilisation or earlier. Astronomy later developed as a discipline of Vedanga, or one of the "auxiliary disciplines" associated with the study of the Vedas dating 1500 BCE or older. The oldest known text is the Vedanga Jyotisha, dated to 1400–1200 BCE (with the extant form possibly from 700 to 600 BCE).
Nicolaus CopernicusNicolaus Copernicus (19 February 1473 – 24 May 1543) was a Renaissance polymath, active as a mathematician, astronomer, and Catholic canon, who formulated a model of the universe that placed the Sun rather than Earth at its center. In all likelihood, Copernicus developed his model independently of Aristarchus of Samos, an ancient Greek astronomer who had formulated such a model some eighteen centuries earlier.
Clock towerClock towers are a specific type of structure which house a turret clock and have one or more clock faces on the upper exterior walls. Many clock towers are freestanding structures but they can also adjoin or be located on top of another building. Some other buildings also have clock faces on their exterior but these structures serve other main functions. Clock towers are a common sight in many parts of the world with some being iconic buildings.
