Matches in DBpedia 2016-04 for { <http://dbpedia.org/resource/Sidereal_time> ?p ?o }
- Sidereal_time abstract "Sidereal time /saɪˈdɪəriəl/ is a time-keeping system astronomers use to keep track of the direction to point their telescopes to view a given star in the night sky. Briefly, sidereal time is a \"time scale that is based on the Earth's rate of rotation measured relative to the fixed stars\" rather than the Sun.From a given observation point, a star found at one location in the sky will be found at nearly the same location on another night at the same sidereal time. This is similar to how the time kept by a sundial can be used to find the location of the Sun. Just as the Sun and Moon appear to rise in the east and set in the west due to the rotation of the Earth, so do the stars. Both solar time and sidereal time make use of the regularity of the Earth's rotation about its polar axis, solar time following the Sun while sidereal time roughly follows the stars. More exactly, sidereal time is the angle, measured from the observer's meridian, along the celestial equator, to the great circle that passes through the March equinox and both poles, and is usually expressed in hours, minutes, and seconds. Common time on a typical clock measures a slightly longer cycle, accounting not only for the Earth's axial rotation but also for the Earth's annual revolution around the Sun of slightly less than 1 degree per day (in fact to the nearest arc-second, it takes 365.2422 daysto revolve therefore 360 degrees/365.2422 days = 0.9856 degrees or 59 arc-minutes, 8 arc-seconds per day, i.e., slightly less than 1 degree per day).A mean sidereal day is 23 hours, 56 minutes, 4.0916 seconds (23.9344699 hours or 0.99726958 mean solar days), the time it takes the Earth to make one rotation relative to the vernal equinox. (Due to nutation, an actual sidereal day is not quite so constant.) The vernal equinox itself precesses slowly westward relative to the fixed stars, completing one revolution in about 26,000 years, so the misnamed sidereal day (\"sidereal\" is derived from the Latin sidus meaning \"star\") is some 0.0084 seconds shorter than the Earth's period of rotation relative to the fixed stars.The longer \"true\" sidereal period is called a stellar day by the International Earth Rotation and Reference Systems Service (IERS). It is also referred to as the sidereal period of rotation, or simply as the period of rotation or the rotational period.Maps of the stars in the night sky use declination and right ascension as coordinates. These correspond to latitude and longitude respectively. While declination is measured in degrees, right ascension is measured in units of time, because it was most natural to name locations in the sky in connection with the time when they crossed the meridian.In the sky, the meridian is the imaginary north to south line that goes through the point directly overhead (the zenith). The right ascension of any object crossing the meridian is equal to the current local (apparent) sidereal time, ignoring for present purposes that part of the circumpolar region north of the north celestial pole (for an observer in the northern hemisphere) or south of the south celestial pole (for an observer in the southern hemisphere) that is crossing the meridian the other way.Because the Earth orbits the Sun once a year, the sidereal time at any given place and time will gain about four minutes against local civil time, every 24 hours, until, after a year has passed, one additional sidereal \"day\" has elapsed compared to the number of solar days that have gone by.".
- Sidereal_time thumbnail ConantClock.png?width=300.
- Sidereal_time wikiPageExternalLink sidereal.html.
- Sidereal_time wikiPageExternalLink sideral.htm.
- Sidereal_time wikiPageExternalLink ai-sidereal.html.
- Sidereal_time wikiPageExternalLink id626626736.
- Sidereal_time wikiPageID "48837".
- Sidereal_time wikiPageLength "18160".
- Sidereal_time wikiPageOutDegree "82".
- Sidereal_time wikiPageRevisionID "702359230".
- Sidereal_time wikiPageWikiLink Anti-sidereal_time.
- Sidereal_time wikiPageWikiLink Astronomer.
- Sidereal_time wikiPageWikiLink Axial_precession.
- Sidereal_time wikiPageWikiLink Category:Horology.
- Sidereal_time wikiPageWikiLink Category:Time_in_astronomy.
- Sidereal_time wikiPageWikiLink Category:Time_scales.
- Sidereal_time wikiPageWikiLink Category:Units_of_time.
- Sidereal_time wikiPageWikiLink Civil_time.
- Sidereal_time wikiPageWikiLink Coordinated_Universal_Time.
- Sidereal_time wikiPageWikiLink Declination.
- Sidereal_time wikiPageWikiLink Diurnal_motion.
- Sidereal_time wikiPageWikiLink Earth.
- Sidereal_time wikiPageWikiLink Earths_rotation.
- Sidereal_time wikiPageWikiLink Ecliptic.
- Sidereal_time wikiPageWikiLink Epoch_(astronomy).
- Sidereal_time wikiPageWikiLink Equinox.
- Sidereal_time wikiPageWikiLink Equinox_(celestial_coordinates).
- Sidereal_time wikiPageWikiLink Extinction_(astronomy).
- Sidereal_time wikiPageWikiLink File:Sidereal_Time_en.PNG.
- Sidereal_time wikiPageWikiLink Fixed_stars.
- Sidereal_time wikiPageWikiLink Geodesy.
- Sidereal_time wikiPageWikiLink Great_circle.
- Sidereal_time wikiPageWikiLink Hour_angle.
- Sidereal_time wikiPageWikiLink International_Earth_Rotation_and_Reference_Systems_Service.
- Sidereal_time wikiPageWikiLink Latitude.
- Sidereal_time wikiPageWikiLink Longitude.
- Sidereal_time wikiPageWikiLink Lunar_month.
- Sidereal_time wikiPageWikiLink March_equinox.
- Sidereal_time wikiPageWikiLink Mean.
- Sidereal_time wikiPageWikiLink Mercury_(planet).
- Sidereal_time wikiPageWikiLink Meridian_(astronomy).
- Sidereal_time wikiPageWikiLink Millisecond.
- Sidereal_time wikiPageWikiLink Moon.
- Sidereal_time wikiPageWikiLink Night_sky.
- Sidereal_time wikiPageWikiLink Nocturnal_(instrument).
- Sidereal_time wikiPageWikiLink Nutation.
- Sidereal_time wikiPageWikiLink Orthogonality.
- Sidereal_time wikiPageWikiLink Overlook.
- Sidereal_time wikiPageWikiLink Parallax.
- Sidereal_time wikiPageWikiLink Planet.
- Sidereal_time wikiPageWikiLink Precession.
- Sidereal_time wikiPageWikiLink Prime_meridian.
- Sidereal_time wikiPageWikiLink Retrograde_and_prograde_motion.
- Sidereal_time wikiPageWikiLink Right_ascension.
- Sidereal_time wikiPageWikiLink Rotation_period.
- Sidereal_time wikiPageWikiLink Sidereal_year.
- Sidereal_time wikiPageWikiLink Solar_time.
- Sidereal_time wikiPageWikiLink Star.
- Sidereal_time wikiPageWikiLink Sun.
- Sidereal_time wikiPageWikiLink Sundial.
- Sidereal_time wikiPageWikiLink Synodic_day.
- Sidereal_time wikiPageWikiLink Telescope.
- Sidereal_time wikiPageWikiLink Tidal_acceleration.
- Sidereal_time wikiPageWikiLink Transit_instrument.
- Sidereal_time wikiPageWikiLink Tropical_year.
- Sidereal_time wikiPageWikiLink United_States_Naval_Observatory.
- Sidereal_time wikiPageWikiLink Universal_Time.
- Sidereal_time wikiPageWikiLink Uranus.
- Sidereal_time wikiPageWikiLink Venus.
- Sidereal_time wikiPageWikiLink Zenith.
- Sidereal_time wikiPageWikiLink File:ConantClock.png.
- Sidereal_time wikiPageWikiLinkText "23h 56m 4.0916s".
- Sidereal_time wikiPageWikiLinkText "Greenwich sidereal time".
- Sidereal_time wikiPageWikiLinkText "Sidereal Time".
- Sidereal_time wikiPageWikiLinkText "Sidereal hour angle".
- Sidereal_time wikiPageWikiLinkText "Sidereal hours".
- Sidereal_time wikiPageWikiLinkText "Sidereal time".
- Sidereal_time wikiPageWikiLinkText "Sidereal".
- Sidereal_time wikiPageWikiLinkText "gradual precession".
- Sidereal_time wikiPageWikiLinkText "local sidereal time".
- Sidereal_time wikiPageWikiLinkText "lunar".
- Sidereal_time wikiPageWikiLinkText "sidereal clock".
- Sidereal_time wikiPageWikiLinkText "sidereal day".
- Sidereal_time wikiPageWikiLinkText "sidereal hour".
- Sidereal_time wikiPageWikiLinkText "sidereal hours".
- Sidereal_time wikiPageWikiLinkText "sidereal period".
- Sidereal_time wikiPageWikiLinkText "sidereal solar calendars".
- Sidereal_time wikiPageWikiLinkText "sidereal time".
- Sidereal_time wikiPageWikiLinkText "sidereal".
- Sidereal_time wikiPageUsesTemplate Template:!.
- Sidereal_time wikiPageUsesTemplate Template:For.
- Sidereal_time wikiPageUsesTemplate Template:Fraction.
- Sidereal_time wikiPageUsesTemplate Template:IPAc-en.
- Sidereal_time wikiPageUsesTemplate Template:Reflist.
- Sidereal_time wikiPageUsesTemplate Template:Time_Topics.
- Sidereal_time wikiPageUsesTemplate Template:Time_measurement_and_standards.
- Sidereal_time wikiPageUsesTemplate Template:Wiktionary.
- Sidereal_time subject Category:Horology.
- Sidereal_time subject Category:Time_in_astronomy.
- Sidereal_time subject Category:Time_scales.