The celestial equator is currently inclined by about 23.44° to the ecliptic plane. The image shows the relations between Earth's axial tilt (or obliquity), rotation axis, and orbital plane.
An observer standing on Earth's equator visualizes the celestial equator as a semicircle passing through the zenith, the point directly overhead. As the observer moves north (or south), the celestial equator tilts towards the opposite horizon. The celestial equator is defined to be infinitely distant (since it is on the celestial sphere); thus, the ends of the semicircle always intersect the horizon due east and due west, regardless of the observer's position on Earth. At the poles, the celestial equator coincides with the astronomical horizon. At all latitudes, the celestial equator is a uniform arc or circle because the observer is only finitely far from the plane of the celestial equator, but infinitely far from the celestial equator itself.[3]
Astronomical objects near the celestial equator appear above the horizon from most places on earth, but they culminate (reach the meridian) highest near the equator. The celestial equator currently passes through these constellations:[4]
These are the most globally visible constellations.
Over thousands of years, the orientation of Earth's equator and thus the constellations the celestial equator passes through will change due to axial precession.
Celestial bodies other than Earth also have similarly defined celestial equators.[5][6]
^ Berger, A.L. (1976). "Obliquity and Precession for the Last 5000000 Years". Astronomy and Astrophysics. 51 (1): 127–135. Bibcode:1976A&A....51..127B.
^Ford, Dominic. "Map of the Constellations". in-the-sky.org. Retrieved 1 Feb 2021.
^Tarasashvili MV, Sabashvili ShA, Tsereteli SL, Aleksidze NG (26 Mar 2013). "New model of Mars surface irradiation for the climate simulation chamber 'Artificial Mars'". International Journal of Astrobiology. 12 (2): 161–170. Bibcode:2013IJAsB..12..161T. doi:10.1017/S1473550413000062.
^"Equal length of day and night on Saturn: the start of spring in the northern hemisphere". German Aerospace Center. Retrieved 1 Feb 2021.
celestial, equator, celestial, equator, great, circle, imaginary, celestial, sphere, same, plane, equator, earth, this, plane, reference, bases, equatorial, coordinate, system, other, words, celestial, equator, abstract, projection, terrestrial, equator, into,. The celestial equator is the great circle of the imaginary celestial sphere on the same plane as the equator of Earth This plane of reference bases the equatorial coordinate system In other words the celestial equator is an abstract projection of the terrestrial equator into outer space 1 Due to Earth s axial tilt the celestial equator is currently inclined by about 23 44 with respect to the ecliptic the plane of Earth s orbit but has varied from about 22 0 to 24 5 over the past 5 million years 2 due to perturbation from other planets The celestial equator is currently inclined by about 23 44 to the ecliptic plane The image shows the relations between Earth s axial tilt or obliquity rotation axis and orbital plane An observer standing on Earth s equator visualizes the celestial equator as a semicircle passing through the zenith the point directly overhead As the observer moves north or south the celestial equator tilts towards the opposite horizon The celestial equator is defined to be infinitely distant since it is on the celestial sphere thus the ends of the semicircle always intersect the horizon due east and due west regardless of the observer s position on Earth At the poles the celestial equator coincides with the astronomical horizon At all latitudes the celestial equator is a uniform arc or circle because the observer is only finitely far from the plane of the celestial equator but infinitely far from the celestial equator itself 3 Astronomical objects near the celestial equator appear above the horizon from most places on earth but they culminate reach the meridian highest near the equator The celestial equator currently passes through these constellations 4 Pisces contains the first point of Aries above its southern border Cetus Taurus Eridanus Orion near Orion s belt Monoceros Canis Minor Hydra Sextans Leo Virgo contains the first point of Libra Serpens caput Ophiuchus Serpens cauda Aquila AquariusThese are the most globally visible constellations Over thousands of years the orientation of Earth s equator and thus the constellations the celestial equator passes through will change due to axial precession Celestial bodies other than Earth also have similarly defined celestial equators 5 6 See also EditCelestial pole Declination Rotation around a fixed axis pole References Edit Celestial Equator Retrieved 5 August 2011 Berger A L 1976 Obliquity and Precession for the Last 5000000 Years Astronomy and Astrophysics 51 1 127 135 Bibcode 1976A amp A 51 127B Millar William 2006 The Amateur Astronomer s Introduction to the Celestial Sphere Cambridge University Press ISBN 978 0 521 67123 1 Ford Dominic Map of the Constellations in the sky org Retrieved 1 Feb 2021 Tarasashvili MV Sabashvili ShA Tsereteli SL Aleksidze NG 26 Mar 2013 New model of Mars surface irradiation for the climate simulation chamber Artificial Mars International Journal of Astrobiology 12 2 161 170 Bibcode 2013IJAsB 12 161T doi 10 1017 S1473550413000062 Equal length of day and night on Saturn the start of spring in the northern hemisphere German Aerospace Center Retrieved 1 Feb 2021 Portals Astronomy Stars Spaceflight Outer space Solar System Retrieved from https en wikipedia org w index php title Celestial equator amp oldid 1129994169, wikipedia, wiki, book, books, library,
