According to various books, one lays out the hour-line angles of a horizontal dial for the latitude, one lays out the hour-line angles of a direct-south vertical dial for the co-latitude, and one lays out the hour-line angles of a reclining direct-south dial for the co-latitude minus the angle of reclination.
I wonder if it would be simpler to say (for northern latitudes) that: 1) The style of the gnomon always points to the (ideal) north star 2) Hour-line angles are laid out by ?D = ARCTAN (TAN t * SIN phi) ?where ?D = hour-line angle ?t = solar hour angle ?phi = angle of style to dial plate This is the usual equation, but I have redefined phi. John B ________________________________________________________________________ Email and AIM finally together. You've gotta check out free AOL Mail! - http://mail.aol.com
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