the measurement of a stellar image
91Timeline of astronomy — Timeline of astronomy2500 BCMany ancient sites are thought to have astronomical significance, such as the Ancient Egyptian pyramids, Harappan shell instruments, British megaliths, and buildings in China and Latin America.In Lothal, the ancient… …
92Nobel Prizes — ▪ 2009 Introduction Prize for Peace The 2008 Nobel Prize for Peace was awarded to Martti Ahtisaari, former president (1994–2000) of Finland, for his work over more than 30 years in settling international disputes, many involving ethnic,… …
93science, history of — Introduction the history of science from its beginnings in prehistoric times to the 20th century. On the simplest level, science is knowledge of the world of nature. There are many regularities in nature that mankind has had to… …
94Betelgeuse — Starbox begin name =Betelgeuse, Alpha OriStarbox image caption = Betelgeuse is the upper left star (pink arrow) in the rectangle of bright stars in Orion.Starbox observe epoch = J2000.0 constell = Orion ra = RA|05|55|10.3053cite web… …
95New Horizons — For other uses, see New Horizons (disambiguation). New Horizons Operator NASA Major contractors Applied Physics Laboratory (APL) Southwest Research Institute (SwRI) …
96Exoplanetology — is the Art and Science of Exoplanets and the search for Life on other Worlds. It is formally defined as the study of the characteristics, formation and fate of planets outside our solar system. The discovery of extrasolar planets or exoplanets in …
97Very Long Baseline Interferometry — (VLBI) is a type of astronomical interferometry used in radio astronomy. It allows observations of an object that are made simultaneously by many telescopes to be combined, emulating a telescope with a size equal to the maximum separation between …
98Sea ice — is largely formed from seawater that freezes. Because the oceans consist of saltwater, this occurs below the freezing point of pure water, at about 1.8 °C (28.8 °F). Sea ice may be contrasted with icebergs, which are chunks of ice shelves or… …
99Megamaser — A megamaser is a type of astrophysical maser, which is a naturally occurring source of stimulated spectral line emission. Megamasers are distinguished from astrophysical masers by their large isotropic luminosity. Megamasers produce roughly 103… …
100F-number — In optics, the f number (sometimes called focal ratio, f ratio, or relative aperture [Smith, Warren Modern Lens Design 2005 McGraw Hill] ) of an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; …
