Wikipedia

Orbital pole: Difference between revisions

Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
Better to say 'focus' here
m convert special characters found by Wikipedia:Typo Team/moss (via WP:JWB)
(9 intermediate revisions by 7 users not shown)
Line 3:
[[File:Snapshot of the planetary orbital poles.png|right|300px|thumb|The north orbital poles of the [[Solar System]] planets all lie within [[Draco (constellation)|Draco]]. The central yellow dot represents the [[Sun]]'s north pole. [[Jupiter]]'s north orbital pole is colored orange, [[Mercury (planet)|Mercury]]'s pale blue, [[Venus]]'s green, [[Earth]]'s blue, [[Mars]]'s red, [[Saturn]]'s magenta, [[Uranus]]'s grey, and [[Neptune]]'s lavender. That of the [[dwarf planet]] [[Pluto]] is shown as the dotless cross off in [[Cepheus (constellation)|Cepheus]].]]
 
An '''orbital pole''' is either point at the ends of the '''orbital normal''', an imaginary [[line segment]] that runs through a [[Focus (geometry)|focus]] of an [[orbit]] (of a revolving body like a [[planet]], [[Natural satellite|moon]] or [[satellite]]) and is [[perpendicular]] to the(or [[orbitalNormal plane(geometry)|normal]]. This imaginary line is referred) to as the ''orbital [[Normalorbital (geometry)|normalplane]]''. Projected onto the [[celestial sphere]], orbital poles are similar in concept to [[celestial pole]]s, but are based on the body's orbit instead of its [[celestial equator|equator]].
 
The [[north]] orbital pole of a revolving body is defined by the [[right-hand rule]]. If the fingers of the right hand are curved along the [[retrograde and prograde motion|direction of orbital motion]], with the thumb extended and oriented to be parallel to the orbital [[axis of rotation|axis]], then the direction the thumb points is defined to be the orbital north.
 
The poles of [[Earth's orbit]] are referred to as the ''[[ecliptic]] poles''. For the remaining planets, the orbital pole in [[ecliptic coordinates]] is given by the [[longitude of the ascending node]] ({{math|☊}}) and [[inclination]] (''{{mvar|i''}}): {{nobr|{{math|''lℓ'' {{=}} ☊ -− 90° }},}} {{nobr|{{math|''b'' {{=}} 90° -− ''i''}} .}} In the following table, the planetary orbit poles are given in both celestial coordinates and the ecliptic coordinates for the Earth.
 
{|class=wikitable
|-
! Object !! [[longitude of the ascending node|{{math|☊}}]]{{refn|name="jpl horizons web"}} !! ''[[inclination|{{mvar|i''}}]]{{refn|name="jpl horizons web"}} !! [[ecliptic longitude|''Ecl.Lon.'']] !! [[ecliptic latitude|''Ecl.Lat.'']] !! [[Right ascension|RA ({{mvar|α}})]] !! [[Declination|Dec ({{mvar|δ}})]]
|- align="right"
| align="left" | [[Mercury (planet)|Mercury]] || 48.331° || 7.005° || 318.331° || 82.995° || align="left" | {{nobr|18 {{sup|h}} 43 {{sup|m}} 57.1 {{sup|s}} }} || align="left" | {{nobr|+61° 26′26{{prime}} 52″52{{pprime}}}}
|- align="right"
| align="left" | [[Venus]] || 76.678° || 3.395° || 346.678° || 86.605° || align="left" | {{nobr|18 {{sup|h}} 32 {{sup|m}} 101.8 {{sup|s}} }} || align="left" | {{nobr|+65° 34′34{{prime}} 1″01{{pprime}}}}
|- align="right"
| align="left" | [[Earth]]
| {{efn|name="coord singularity"}}140° || 0.0001° || {{efn|name="coord singularity"}}50° || 89.9999° || align="left" | {{nobr|18 {{sup|h}} 0 00{{sup|m}} 00.0 {{sup|s}} }} || align="left" | {{nobr|+66° 33′33{{prime}} 38.84″84{{pprime}}}}
|- align="right"
| align="left" | [[Mars]] || 49.562° || 1.850° || 319.562° || 88.150° || align="left" | {{nobr|18 {{sup|h}} 13 {{sup|m}} 29.7 {{sup|s}} }} || align="left" | {{nobr|+65° 19′19{{prime}} 22″22{{pprime}}}}
|- align="right"
| align="left" | [[Ceres (dwarf planet)|Ceres]] || 80.494° || 10.583° || 350.494° || 79.417° || align="left" | {{nobr|19 {{sup|h}} 33 {{sup|m}} 33.1 {{sup|s}} }} || align="left" | {{nobr|+62° 50′50{{prime}} 57″57{{pprime}}}}
|- align="right"
| align="left" | [[Jupiter]] || 100.492° || 1.305° || 10.492° || 88.695° || align="left" | {{nobr|18 {{sup|h}} 13 {{sup|m}} 000.8 {{sup|s}} }} || align="left" | {{nobr|+66° 45′45{{prime}} 53″53{{pprime}}}}
|- align="right"
| align="left" | [[Saturn]] || 113.643° || 2.485° || 23.643° || 87.515° || align="left" | {{nobr|18 {{sup|h}} 23 {{sup|m}} 46.8 {{sup|s}} }} || align="left" | {{nobr|+67° 26′26{{prime}} 55″55{{pprime}}}}
|- align="right"
| align="left" | [[Uranus]] || 73.989° || 0.773° || 343.989° || 89.227° || align="left" | {{nobr|18 {{sup|h}} 7 07{{sup|m}} 24.1 {{sup|s}} }} || align="left" | {{nobr|+66° 20′20{{prime}} 12″12{{pprime}}}}
|- align="right"
| align="left" | [[Neptune]] || 131.794° || 1.768° || 41.794° || 88.232° || align="left" | {{nobr|18 {{sup|h}} 13 {{sup|m}} 54.1 {{sup|s}} }} || align="left" | {{nobr|+67° 42′42{{prime}} 8″08{{pprime}}}}
|- align="right"
| align="left" | [[Pluto]] || 110.287° || 17.151° || 20.287° || 72.849° || align="left" | {{nobr|20 {{sup|h}} 56 {{sup|m}} 3.7 {{sup|s}} }} || align="left" | {{nobr|+66° 32′32{{prime}} 31″31{{pprime}}}}
|}
When a satellite orbits close to another large body, it can only maintain continuous observations in areas near its orbital poles. The continuous viewing zone (CVZ) of the [[Hubble Space Telescope]] lies inside roughly 24° of Hubble's orbital poles, which [[Precession|precess]] around the Earth's axis every 56 days.<ref>{{Citecite web |title=HST Cycle cycle&nbsp;26 Primerprimer Orbitalorbital Constraints -constraints |department=HST User Documentation |url=https://hst-docs.stsci.edu/hsp/past-hst-proposal-opportunities/the-hubble-space-telescope-primer-for-cycle-26/hst-cycle-26-primer-orbital-constraints |access-date=2022-07-16 |website=hst-docs.stsci.edu}}</ref>
 
==Ecliptic Pole==
Line 54:
It is impossible anywhere on Earth for either ecliptic pole to be at the [[zenith]] in the [[night sky]]. By definition, the ecliptic poles are located 90° from the [[position of the Sun|Sun's position]]. Therefore, whenever and wherever either ecliptic pole is directly overhead, the Sun must be on the [[horizon]]. The ecliptic poles can contact the zenith only within the [[Arctic Circle|Arctic]] and [[Antarctic Circle|Antarctic]] circles.
 
The [[galactic coordinates]] of the North ecliptic pole can be calculated as {{nobr|{{math|''lℓ'' {{=}}&nbsp;=&nbsp; 96.38°}},}} {{nobr|{{math|''b'' {{=}}&nbsp;=&nbsp; 29.81°}} }} (see [[Celestialcelestial coordinate system]]).
 
==See also==
Line 67:
}}
{{Reflist|refs=
<ref name="jpl horizons web">Data from {{Cite web|title=HORIZONS Web-Interface|url=https://ssd.jpl.nasa.gov/horizons.cgi?s_type=1|url-status=live|access-date=2020-09-01|website=[[Jet Propulsion Laboratory|JPL]] Solar System Dynamics|publisher=[[NASA]]}} Used “Ephemeris"Ephemeris Type: Orbital Elements”Elements", “Time"Time Span: discrete time=2451545”2451545", “Center"Center: Sun (body center)”", and selected each object's barycenter. Results are instantaneous osculating values at the precise J2000 epoch, and referenced to the ecliptic.</ref>
}}
 
Retrieved from "https://en.wikipedia.org/wiki/Orbital_pole"