Image:Gibbous-Crescent-half-ellipse-in-circle.png

A vector version of this image (SVG) is available. It should be used in place of this raster image when superior. Image:Gibbous-Crescent-half-ellipse-in-circle.png  Image:Gibbous-Crescent-half-ellipse-in-circle.svg For more information about vector graphics, read about Commons transition to SVG. There is also information about MediaWiki's support of SVG images. Български | Deutsch | English | Español | Français | Galego | עברית | Magyar | Bahasa Indonesia | Italiano | 日本語 | 한국어 | Lietuvių | Polski | Português | Русский | Српски / Srpski | Українська | ‪中文(简体)‬ | ‪中文(繁體)‬ | +/-

[edit] Summary

A circle divided into a gibbous shape (red) and an astronomical crescent shape (blue) by a half-ellipse, where the major axis of the ellipse coincides with a diameter of the circle. According to geometry, an illuminated hemisphere of a sphere will appear to take on such gibbous or crescent shapes when viewed from an angle. In this case, the length of the major axis of the ellipse is twice the length of the minor axis (i.e. the eccentricity is half the square root of 3), so that the red gibbous area shows the theoretical shape of the visible lit area of the moon (for example) when the separation between the viewing angle and the angle of illumination (i.e. between Earth and Sun) is 60 degrees, while the blue crescent area shows the theoretical shape of the visible lit area of a sphere when the separation between the viewing angle and the angle of illumination is 120 degrees. See also Image:Gibbous-Crescent-half-ellipse-in-circle-outlined.png

Generated by means of the following PostScript code:

%!
.75 0 0 setrgbcolor
306 396 144 0 360 arc
fill
0 .2 .85 setrgbcolor
306 396 144 90 -90 arcn 
39.765 0 72 64.471 72 144 rcurveto
0 79.529 -32.235 144 -72 144 rcurveto
closepath
fill
showpage
%%EOF

[edit] Licensing

I, the copyright holder of this work, hereby release it into the public domain. This applies worldwide. In case this is not legally possible: I grant anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. Afrikaans | Alemannisch | Aragonés | العربية | Asturianu | Български | Català | Česky | Cymraeg | Dansk | Deutsch | Eʋegbe | Ελληνικά | English | Español | Esperanto | Euskara | Estremeñu | فارسی | Français | Galego | 한국어 | हिन्दी | Hrvatski | Ido | Bahasa Indonesia | Íslenska | Italiano | עברית | Kurdî / كوردی | Latina | Lietuvių | Latviešu | Magyar | Македонски | Bahasa Melayu | Nederlands | ‪Norsk (bokmål)‬ | ‪Norsk (nynorsk)‬ | 日本語 | Polski | Português | Ripoarisch | Română | Русский | Shqip | Slovenčina | Slovenščina | Српски / Srpski | Svenska | ไทย | Tagalog | Türkçe | Українська | Tiếng Việt | Walon | ‪中文(简体)‬ | ‪中文(繁體)‬ | zh-yue-hant | +/-