Search results
Results from the WOW.Com Content Network
The equation of time describes the discrepancy between two kinds of solar time. The word equation is used in the medieval sense of "reconciliation of a difference". The two times that differ are the apparent solar time , which directly tracks the diurnal motion of the Sun , and mean solar time , which tracks a theoretical mean Sun with uniform ...
Right ascension is the celestial equivalent of terrestrial longitude. Both right ascension and longitude measure an angle from a primary direction (a zero point) on an equator. Right ascension is measured from the Sun at the March equinox i.e. the First Point of Aries, which is the place on the celestial sphere where the Sun crosses the ...
Date of Easter. A calendar of the dates of Easter, for the 95 years 532–626, marble, in the Museum of Ravenna Cathedral, Italy. Five 19-year cycles are represented as concentric circles. Dates are given using the system of the Roman calendar, as well as the day of the lunar month. As a moveable feast, [1][2] the date of Easter is determined ...
Animation showing the difference between a sidereal day and a solar day. Sidereal time ("sidereal" pronounced / saɪˈdɪəriəl, sə -/ sy-DEER-ee-əl, sə-) is a system of timekeeping used especially by astronomers. Using sidereal time and the celestial coordinate system, it is easy to locate the positions of celestial objects in the night sky.
Sunrise equation. A contour plot of the hours of daylight as a function of latitude and day of the year, using the most accurate models described in this article. It can be seen that the area of constant day and constant night reach up to the polar circles (here labeled "Anta. c." and "Arct. c."), which is a consequence of the earth's inclination.
Time is the continued sequence of existence and events that occurs in an apparently irreversible succession from the past, through the present, and into the future. [1] [2] [3] It is a component quantity of various measurements used to sequence events, to compare the duration of events or the intervals between them, and to quantify rates of change of quantities in material reality or in the ...
A calendrical calculation is a calculation concerning calendar dates. Calendrical calculations can be considered an area of applied mathematics. Some examples of calendrical calculations: Converting a Julian or Gregorian calendar date to its Julian day number and vice versa (see § Julian day number calculation within that article for details ...
Minute is a unit of time defined as equal to 60 seconds. [1] One hour contains 60 minutes. [2] Although not a unit in the International System of Units (SI), the minute is accepted for use in the SI. [1] The SI symbol for minutes is min (without a dot). The prime symbol ′ is also sometimes used informally to denote minutes. [3]