File talk:Geometry of a Lunar Eclipse.svg

This diagram is extremely misleading; the sun's distance from the Earth-moon system is so great that its rays are essentially parallel, and their minimal convergence plays no role in the penumbra/umbra relationship. Hgilbert (talk) 14:39, 16 March 2008 (UTC)[reply]

All eclipse diagrams I've seen show exaggerated body diameters so the difference between the umbral and penumbral shadows can be shown. Perhaps two images could be used, one with true diameters relative to the orbits? It is a curious question - how far out the earth's umbral shadow extends, although I expect it is about 4 moon orbit radii. SockPuppetForTomruen (talk) 17:01, 16 March 2008 (UTC)[reply]

The difference between the shadows does not depend on the convergence or parallel-ness of the sun's rays; separate issue. Hgilbert (talk) 23:26, 16 March 2008 (UTC)[reply]

I'm not sure what you mean. If the sun was a "point light source", there'd be no parallax, no penumbral shadow. If you draw a true-body size diagram, the angles are too tiny to see at any scale. What exactly do you propose as an alternative? SockPuppetForTomruen (talk) 06:23, 17 March 2008 (UTC)[reply]