Greetings All, i'm working through Drinkwater's _Art of Sundial Construction_ (which i very much like) but have encountered a problem that perhaps someone can help me with. i have two problems in his section on marking the "Parallels of Solar Declination" (pp. 44-46).
First, on p.45 he says "Construct the Maneus as Shewn." But when i try to reproduce his equivalent on p.46, i can't figure out how to fix the distance of the center of the "zodiacal circle" from point D. it seems that the hour line he labels "6" fixes that distance, but that distance couldn't have come from the diagram on p.44 (as do the lengths of the other hour lines) because the 6 line is parallel to the common tangent line and never intersects it. what am i missing here? Second, (and assuming the first is solved) he instructs us to "Take the requisite distances, to the individual "Parallels", along each Hour Line on the second Diagram from Points 'A' and 'B', and transfer them to the corresponding Hour Lines on the Dial." what distance from 'A', for example, is this? shall i measure along the 8 line, for example, from 'A', extend this line through the horizontal from 'D', and take the distance where the 8 line intersects, say, the line for Taurus? this makes a certain amount of sense to me, but then how shall i complete the lines on the winter side of the equinoctial line on the dial face (e.g. where does 8 intersect Aquarius) for a simple horizontal dial? (as opposed to his more complex example of a diptych dial.) thanks for any insights. -jim lattis -- Jim Lattis [EMAIL PROTECTED] "What's so amazing that Space Astronomy Lab voice: 608-263-0360 keeps us stargazing, and History of Science Dept. fax: 608-263-0361 what do we think we might Univ. of Wisconsin-Madison see?" -Kermit t. Frog
