Definitions for sidereal time
side·re·al time

Princeton's WordNetRate this definition:0.0 / 0 votes

1. sidereal timenoun

   measured by the diurnal motion of stars

WiktionaryRate this definition:0.0 / 0 votes

1. sidereal timenoun

   Time measured by the apparent diurnal motion of the vernal equinox; approximated by that based on the rotation of the Earth relative to the stars

WikipediaRate this definition:0.0 / 0 votes

1. Sidereal time

   Sidereal time (as a unit also sidereal day or sidereal rotation period) (sidereal sy-DEER-ee-əl, sə-) is a timekeeping system that astronomers use to locate celestial objects. Using sidereal time, it is possible to easily point a telescope to the proper coordinates in the night sky. Sidereal time is a "time scale that is based on Earth's rate of rotation measured relative to the fixed stars", or more correctly, relative to the March equinox. Viewed from the same location, a star seen at one position in the sky will be seen at the same position on another night at the same sidereal time. This is similar to how the time kept by a sundial (Solar time) 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 Earth, so do the stars. Both Solar time and sidereal time make use of the regularity of Earth's rotation about its polar axis: solar time follows the Sun while, roughly speaking, sidereal time follows the distant fixed stars on the celestial sphere. More exactly, sidereal time is the angle, measured along the celestial equator, from the observer's meridian to the great circle that passes through the March equinox and both celestial poles, and is usually expressed in hours, minutes, and seconds. Common time on a typical clock (mean Solar time) measures a slightly longer cycle, accounting not only for Earth's axial rotation but also for Earth's orbit around the Sun. A sidereal day on Earth is approximately 86164.0905 seconds (23 h 56 min 4.0905 s or 23.9344696 h). (Seconds here follow the SI definition and are not to be confused with ephemeris second.) The March equinox itself precesses slowly westward relative to the fixed stars, completing one revolution in about 25,800 years, so the misnamed sidereal day ("sidereal" is derived from the Latin sidus meaning "star") is 0.0084 second shorter than the stellar day, Earth's period of rotation relative to the fixed stars. The slightly longer "true" sidereal period is measured as the Earth Rotation Angle (ERA), formerly the stellar angle. An increase of 360° in the ERA is a full rotation of the Earth. Because 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.

ChatGPTRate this definition:0.0 / 0 votes

1. sidereal time

   Sidereal time is a time-keeping system used by astronomers to track the position of celestial objects in the sky. It is measured by the rotation of the Earth relative to the stars, rather than relative to the Sun. A sidereal day, therefore, is the time it takes for a given star to return to the same position in the sky, approximately 23 hours 56 minutes and 4.1 seconds.

WikidataRate this definition:0.0 / 0 votes

1. Sidereal time

   Sidereal time 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, a sidereal day is a "time scale that is based on the Earth's rate of rotation measured relative to the fixed stars." 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 follows the vernal equinox, which is not quite fixed among the stars; precession and nutation shift the equinox slightly from one day to the next, so sidereal time is not an exact measure of the rotation of the Earth relative to inertial space. 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.

Dictionary of Nautical TermsRate this definition:0.0 / 0 votes

1. sidereal time

   The time shown by a clock regulated by the fixed stars, and compensated to accelerate upon mean time by the daily amount of 3 minutes 56·56 seconds.

Matched Categories

1. • Cosmic Time

How to pronounce sidereal time?

1. Alex

   US English

   David

   US English

   Mark

   US English

   Daniel

   British

   Libby

   British

   Mia

   British

   Karen

   Australian

   Hayley

   Australian

   Natasha

   Australian

   Veena

   Indian

   Priya

   Indian

   Neerja

   Indian

   Zira

   US English

   Oliver

   British

   Wendy

   British

   Fred

   US English

   Tessa

   South African

How to say sidereal time in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of sidereal time in Chaldean Numerology is: 2

2. Pythagorean Numerology

   The numerical value of sidereal time in Pythagorean Numerology is: 3

References

1. ^ Princeton's WordNet
   http://wordnetweb.princeton.edu/perl/webwn?s=sidereal time
2. ^ Wiktionary
   https://en.wiktionary.org/wiki/Sidereal_Time
3. ^ Wikipedia
   https://en.wikipedia.org/wiki/Sidereal_Time
4. ^ ChatGPT
   https://chat.openai.com
5. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=sidereal time
6. ^ Dictionary of Nautical Terms
   https://www.gutenberg.org/cache/epub/26000/pg26000-images.html#:~:text=sidereal time