Chris Lusby Taylor wrote: > ....The Team Disney sundial > (http://www.fsec.ucf.edu/~at/disndial.htm) is much bigger: 120' (over > 36 metres) high. But it does not have a complete horizontal dial 120' > below the gnomon, so its area is quite small.
I decided to try and approximate the area of the inside of the Disney dial. I made the simplifying assumption that the top circle is not displaced some 6.8 feet from the bottom one. Then I peeled the inverted truncated cone to place it on a plane, with an approximate shape of a trapezoid having a 377 ft base (circumference of the 120 ft diameter bottom circle), a 121 ft height (Pythagorean theorem applied to the tilted side of the cone), and a 264 ft top (circumference of the 84 ft diameter top circle). The area of this trapezoid is 38,774 sq. ft. We probably should add the area of the floor too (pi times 60 ft squared), 11,310 sq. ft, to get about 50,000 square feet total. I've attached jpg files of the wall and floor markings, projected onto a flat plane, for those able to view such images. I used the 640 x 480 pixels setting so the drawings won't be too big in bytes or area. >From these drawings I estimate that the sunpath lines and hour markings on the wall and floor of this dial to be a little less than half the total wall and floor area, giving a dial markings area of somewhere around 20,000 square feet. The whole cone is structurally part of the dial, however, so I would argue in favor of counting the total area. The problem, of course, is how one goes about measuring "bigness." Height alone is not enough. Volume is not enough. Area is not enough. Largest linear dimension is not enough. Perhaps we could come up with a weighted sum of all four. Anyone want to suggest some weighting factors? The questions of accuracy and usefulness are good ones, but these should be included in some other measure of a sundial. Then we could all join in a race to have not only the largest sundial, or the most accurate, but the largest AND most accurate. Would it be too much to ask it to be the most useful as well? Of course much of this discussion borders on the silly. But its kind of fun to compare dials, in lots of different ways. Ross McCluney Cocoa, Florida USA Attachment converted: MAC Hard Disk:WALLMAP6.jpg (JPEG/JVWR) (00002BDC) Attachment converted: MAC Hard Disk:DISFLOR4.jpg (JPEG/JVWR) (00002BDD)
