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Re: sun's distance as lab exercise?



The instant of quadrature of the Moon cannot be determined sufficiently
accurately to measure the distance ratio. The method was tried, and I
believe the result was that the Sun is twenty times more distant than
the Moon, an error of about a factor of twenty. The angle involved is
about 1/7 of a degree. Determination to an uncertainty of ten percent
would require determination of the times of quadrature to an accuracy
of about one hundred seconds.

I have tried similar things with my favorite planetarium emulator,
Starry Night Pro. If your students want to try, the data you are
seeking (longitudes of positions with Sun and Moon in the zenith at
quadrature) can be obtained using this tool. As a practical matter,
however, it can't be done.

Leigh