File:Gibbous-Crescent-half-ellipse-in-circle.svg

Original file (SVG file, nominally 612 × 612 pixels, file size: 220 bytes)

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Summary

Description	A circle divided into a gibbous shape (light grey) and an astronomical crescent shape (dark grey) 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 light grey 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 dark grey 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.
Source	Own work based on: Gibbous-Crescent-half-ellipse-in-circle.png
Author	AnonMoos
Other versions	Outlined
SVG development InfoField	The SVG code is valid. This trigonometry was created with a text editor.

Converted from 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

Licensing

This work 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.

File history

Click on a date/time to view the file as it appeared at that time.

	Date/Time	Dimensions	User	Comment
current	13:33, 13 July 2021	612 × 612 (220 bytes)	Sarang	was unvalidable // Editing SVG source code using c:User:Rillke/SVGedit.js
	01:41, 28 March 2016	612 × 612 (199 bytes)	KohanX	Removed the dependency on color for information, to make it more accessible to color-deficient humans. It can now be referred to as shaded and unshaded areas instead of blue and red areas.
	15:43, 7 November 2011	612 × 612 (562 bytes)	AnonMoos	adjust margins, simplify code
	02:14, 3 July 2006	612 × 612 (672 bytes)	AnonMoos	compact exact PS conversion with margins
	10:17, 16 June 2006	500 × 500 (2 KB)	Ttog~commonswiki	== 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 sphe