[EMAIL PROTECTED] (John Carmichael) writes: > It's an interesting thought to use the moon's shadow at sunrise and sunset > on the equinox to locate your east-west points. Although this can be done > with the sun, you would have errors using the moon, unless there is an > eclipse on the equinox also. If the moon is not in the same plane as the > sun, it will not act like the sun. > > Since the moon moves about two minutes/hour eastward in the sky, the only > way you can do this with precision is to use precisely calculated times and > lunar coordinates such as those sent to you by Jim Cobb. First you would > find the meridian with the moon, using Jim's data, then find east/west.
Of course, the moon doesn't cast shadows during an eclipse, so we are really talking about taking a sight on the moon. Even during a total eclipse, without additional information, the errors will be several times larger than using the sun. If you have additional information, i.e., the coordinates of the heavenly bodies at various times, then there is no need to wait for the solstice or an eclipse, you can take a sight on anything at any time and deduce the cardinal directions from the result. I think the purist's way to find directions (a purist being a Druid with the knowledge and technology of Stonehenge), is to mark the directions of sunrise and sunset for a few days near the solstice. By interpolation, you can get the hypothetical direction to the rising sun for each hour of the period in question, and likewise for the setting sun. For one of these hours, the directions will be exactly opposed to each other. This is East/West, and the hour is the exact time of the equinox. Magic. Have fun out there with the coyotes! Art
