Useful english dictionary. 2012.
Lunar calendar — A lunar calendar is a calendar that is based on cycles of the lunar phase. A common purely lunar calendar is the Islamic calendar or Hijri calendar. A feature of the Islamic calendar is that a year is always 12 months, so the months are not… … Wikipedia
Lunar distance (navigation) — For the history of the lunar distance method, see History of longitude. Finding Greenwich time while at sea using a lunar distance. The Lunar Distance is the angle between the Moon and a star (or the Sun). The altitudes of the two bodies are used … Wikipedia
Equation of time — Time Time, n.; pl. {Times}. [OE. time, AS. t[=i]ma, akin to t[=i]d time, and to Icel. t[=i]mi, Dan. time an hour, Sw. timme. [root]58. See {Tide}, n.] 1. Duration, considered independently of any system of measurement or any employment of terms… … The Collaborative International Dictionary of English
Equation of the center — The equation of the center, in astronomy and elliptical motion, is equal to the true anomaly minus the mean anomaly, i.e. the difference between the actual angular position in the elliptical orbit and the position the orbiting body would have if… … Wikipedia
solar equation — noun : the correction of the epacts by 1 required in each century of the Gregorian calendar that begins with a common year instead of a leap year compare lunar equation … Useful english dictionary
Orbit equation — In astrodynamics an orbit equation defines the path of orbiting body around central body relative to , without specifying position as a function of time. Under standard assumptions, a body moving under the influence of a force, directed to a… … Wikipedia
Epact — • The surplus days of the solar over the lunar year; hence, more freely, the number of days in the age of the moon on 1 January of any given year. The whole system of epacts is based on the Metonic Lunar Cycle, and serves to indicate the days of… … Catholic encyclopedia
Aloisius Lilius — Aloisius Lilius † Catholic Encyclopedia ► Aloisius Lilius Aloisius Lilius, principal author of the Gregorian Calendar, was a native of Cirò or Zirò in Calabria. His name was originally Aloigi Giglio, from which the Latinized form now… … Catholic encyclopedia
Computus — (Latin for computation ) is the calculation of the date of Easter in the Christian calendar. The name has been used for this procedure since the early Middle Ages, as it was one of the most important computations of the age. In principle, the… … Wikipedia
Epact — The epact (from Greek: epaktai hèmerai = added days) is a quantification of the difference between the solar and lunar calendars. It was defined by the second canon of the Gregorian calendar reform as the number of days by which the common solar… … Wikipedia
