6: Limb Darkening
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Limb darkening is an optical effect seen in stars (including the Sun), where the center part of the disk appears brighter than the edge or limb of the image.
Thumbnail: A filtered image of the Sun in visible light, showing the limb-darkening effect as a dimmer luminosity towards the edge or limb of the solar disk. The image was taken during the 2012 transit of Venus (seen here as the dark spot at the upper right). (CC BY 2.5;
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