Hi guys, it's me again: Just thought of another fun experiment we can do during the Jan. 31 lunar eclipse. One person wrote saying that he doubted there would be enough light during a prenumbral eclipse to cast a shadow on a sundial. If you have a photometer, you could measure the minimum amount of light in foot-candles (or lumens) that is needed to cast a shadow. You can also note how far into the eclipse this occurs. I realize that results should vary depending on local ambient light pollution.
Knowing, in foot-candles, the minimum amount of light needed to activate a sundial, how far away from the sun would you have to go until the sun doesn't cast a shadow? John Carmichael
