ملخص

الوصفGibbous-Crescent-half-ellipse-in-circle.svg	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.
المصدر	Own work based on: Gibbous-Crescent-half-ellipse-in-circle.png
المؤلف	AnonMoos
إصدارات أخرى	Outlined
SVG منشأ الملف InfoField	الشيفرة المصدرية لهذا الرسم المتجه صالحة.   This trigonometry was created with a text editor.

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ترخيص

وضع -AnonMoos-، وهو المؤلف، هذا العمل في النِّطاق العامِّ. يسري ذلك في كل أرجاء العالم. في بعض البلدان، قد يكون هذا التَّرخيص غيرَ مُمكنٍ قانونيَّاً، في هذه الحالة: يمنح AnonMoos الجميع حق استخدام هذا العمل لأي غرض دون أي شرط ما لم يفرض القانون شروطًا إضافية.