In this unit, we will review some words related to astronomy, the science and study of stars, planets and space. Altitude is the angular position of a celestial body in relation to the observer's horizon, which is measured in degrees. Apogi is a point in the orbit of a moon or any such satellite that is farthest from the center of a planet. Perigee is a point in the orbit of the moon or any such satellite that is nearest to the center of the planet. Ascension is an astronomical term used to measure the angular distance of a celestial object with reference to a point on the celestial equator and the Earth equator. Asteroids are large rocks, the size of minor planets that orbit the Sun. Millions of asteroids orbit in the asteroid belt located between the orbits of Mars and Jupiter. Astronomer is an expert to observe celestial objects and other celestial phenomena. Astronomical is an adjective that refers to anything related to the field of astronomy. Asimuth is the angular distance of a celestial body from the north or south point of the observer's horizon. Comet is a small icy object that orbits the Sun and has a long tail of gas and dust. Conjunction happens when two planets or celestial objects appear to be in the same position in the sky. Constellation is a group of stars that form a recognizable pattern in the sky. The Orion or the Hunter constellation is shown here. Cosmogenic is an isotope of a material produced by the action of cosmic rays. Cosmogony is a study of the origin of the universe. Cosmography is a branch of science that deals with the physical features of the universe. Cosmology is a branch of astronomy dealing with the origin of the universe. Deckling Nation is the angular distance of a celestial object in relation to the Earth. Epoch is a phase in the development of the universe after the Big Bang. Equinox refers to the two days in the year when the nights and days are of equal length. This happens at the time the Sun crosses the celestial equator. Soul stress refers to either of the two days in a year when the Sun is farthest from the celestial equator. Galaxi consists of billions of stars and planets held together by gravitational force. Our home galaxy, the Milky Way, contains in the range of 100 to 400 billion stars. Horizon is the boundary where the sky appears to meet the land. Latitude is any parallel circle located on either of the hemisphere of the Earth that runs east to west and is parallel to the equator. Load star is a star that acts as a guide in the sky during navigation. Luminosity is actual brightness of energy radiated by a star per unit time. Meteor is a rock that enters the Earth's atmosphere and appears to be shining due to the heat produced by friction. Meteoroid is a former stage of a meteor before it enters the Earth's atmosphere. Nadir is a point on the celestial sphere that is located directly below the observer. Zenith is a point on the celestial sphere located directly above the observer. Navigation refers to celestial navigation or astronavigation which involves determining the position of celestial bodies by using the Sun, Moon and stars as reference points. Nephila is a massive cloud of dust and gases in outer space that is the birthplace of new stars. Observatory is a building that houses huge scientific telescopes from which observations are made to study astronomical and meteorological phenomena. Partsack is an astronomical unit to measure distance which equals 3.26 light years. Planetarium is a domed building in which informative videos and presentations about astronomical phenomena are displayed. Quadrant is an instrument used to measure angular distance between celestial objects. Quadrant is the ancestor of the more contemporary sextant which is still used today by some nautical navigators. Satellite is a celestial body that orbits around the planet, also refers to an artificial device that is positioned to orbit around the Earth to collect and relay information. Sidee real is an adjective that means off or relating to the stars or constellations. Star is a celestial body that emits light that is generated by nuclear reactions in its center. Sisegi happens when three celestial bodies like the Sun, Moon and Earth are in a straight line configuration. Tropic refers to any of the two parallel in the celestial sphere that correspond to the northern and southern passages of the Sun. We have the tropic of cancer and the tropic of Capricorn. If you enjoyed this video, please like share and subscribe for more details visit our website neximagine.com