Frank,I made a horizontal altitude dial for the inside of a box. The date lines are parallel to 2 edges, one of the other 2 edges is the shadow casting object. The box has to be rotated to the sun so that the vertical edges parallel to the date lines point to the direction of sun (cast no shadow transversal to their direction)
I calculated that with my software SONNE.EXE. I hope the attache image is not blocked. Otherwise send me a mail. Helmut Sonderegger www.helson.at----- Original Message ----- From: "Frank Evans" <frankev...@zooplankton.co.uk>
To: "Sundial" <sund...@rrz.uni-koeln.de> Sent: Wednesday, January 26, 2011 12:12 PM Subject: re altitude dial
Greetings, fellow dialists,Thanks, all, for the communications. I think I did not make it clear that I was thinking of a horizontal altitude dial, not a vertical one. It would look a bit like an analemmatic dial laid out on the ground. I understand how a shepherd's dial works and also how a vertical altitude dial with (say) six curves works. I have a nice picture of the altitude (and azimuth) dial once to be seen on a wall in the Royal Observatory at Greenwich. It has now, alas, been lost, together with the other five dials (planetary hours, equal hours, zodialcal signs, equation of time, hours from sunrise and sunset) made by a Polish dialist whose name I have sadly forgotten.The vertical altitude dial at Greenwich was very plain and simply had a fixed horizontal sun-hole gnomon with altitude curves (and vertical azimuth lines) beneath it. I envisage a horizontal dial with a single altitude curve and the vertical gnomon moving north -south to compensate for seasonal change. Is such a dial possible?Frank 55N 1W --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
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