Image:Gibbous-Crescent-half-ellipse-in-circle-outlined.svg

[edit] Summary

A circle divided into a gibbous shape (left) and an astronomical crescent shape (right) 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 larger 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 smaller 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.svg

SVG version of Image:Gibbous-Crescent-half-ellipse-in-circle-outlined.png

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This image has been released into the public domain by its author, AnonMoos. This applies worldwide. In some countries this may not be legally possible; if so: AnonMoos grants anyone the right to use this work for any purpose, without any conditions, unless such conditions are required by law. العربية | Български | Deutsch | Ελληνικά | English | Español | Français | Italiano | 日本語 | 한국어 | Polski | Русский | Српски / Srpski | Svenska | தமிழ் | Українська | ‪中文(繁體)‬ | ‪中文(简体)‬  +/-