File:Lunar libration with phase2.gif

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This image was selected as picture of the day on Wikimedia Commons for 9 August 2006. It was captioned as follows: English: Lunar libration Other languages:  العربية: الهلال لحظة تكوينه Cymraeg: Gweddau'r Lleuad. Deutsch: Der Mond in seinen unterschiedlichen Phasen. English: Lunar libration Español: Fases y libración de la Luna. Français : Les différentes phases de la Lune Gaeilge: Guagadh na Gealaí. Galego: Fases da lúa e oscilación lunar Magyar: A Hold librációja (ciklikus imbolygása) Italiano: Le librazioni e le fasi lunari. 日本語: 月の秤動 Bân-lâm-gú: Ge̍h-niû tī-leh piàn-hòa ê kè-thêng tang-tiong, lán lâng só· koan-chhek tio̍h ê thian-bûn hiān-siōng. Norsk bokmål: Månens faser. Norsk nynorsk: Månefasane Polski: Animacja ukazująca Księżyc we wszystkich fazach. Português: Animação representando as fases da lua Русский: Либрация Луны Slovenčina: Librácia Mesiaca Svenska: Månens librationer Türkçe: Ayın evreleri 中文（简体）‎: 月相变化

Summary

Licensing

I, the copyright holder of this work, release this work into the public domain. This applies worldwide. In some countries this may not be legally possible; if so: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. Public domainPublic domainfalsefalse

Technical

• Book: "Astronomical Formulae for Calculators, 4th edition", Jean Meeus, 1988, published by "Willmann-Bell, Inc"
  • Chapter 30 "Position of the Moon"

Source bitmap for projection from NRL's Clementine Spacecraft:

• Animation
  • 50 frames were created, equally spaced in time.
  • Period used: 27.21222 days (Draconic month of nodes)
  • Animation began and ended at Apogee to minimize "jumping" when cycles back to the start.
  • New moon given an unreal 1% intensity "Ambient light" to show motion in all phases.
  • View assumed from the centre of the earth. (Geometrically impossible, but best demonstration of monthly libration caused by moon's motion versus the shorter daily libration that would be included from the surface of the earth.)

Astronomical events

• Sept 1, 2:23 UT - Apogee - Moon farthest from earth's centre [Cancer]
• Sept 3, 1:48 UT - New Moon [Leo]
• Sept 6, 10:53 UT - Descending Node - On ecliptic circle, heading north to south. [Virgo]
• Sept 11, 11:40 UT - First Quarter - Rises around noon, and at zenith near sunset [Scorpio]
• Sept 13, 6:21 UT - Southern Limit - At farthest ecliptic south of the moon's orbit. [Sagittarius]
  • Also near farthest south declination as well.
• Sept 16, 13:54 UT - Perigee - Closest point on orbit to earth's centre. [Aquarius]
• Sept 18, 2:04 UT - Full Moon - A "large and southern" moon up all night! [Pisces]
• Sept 18, 8:11 UT - Ascending Node - On ecliptic, heading south to north. [Pisces]
• Sept 25, 6:44 UT - Third Quarter - Rises after midnight, near zenith around sunrise. [Gemini]
• Sep 26, 5:17 UT - Northern Limit - At farthest ecliptic north point of the moon's orbit. [Gemini]
  • Also near farthest north declination as well.
• Sep 28, 15:31 UT - Apogee - Farthest point on orbit from earth's centre. [Cancer]

Valued image This image has been assessed under the valued image criteria and is considered the most valued image on Commons within the scope: Lunar phases. You can see its nomination at Commons:Valued image candidates/Lunar libration with phase2.gif.