Msg: 7021 *Conference*
03-27-97 19:26:42
From: RON WIESEN
To : COMET _
Subj: REPLY TO MSG #7018 (CYBERLIFE)
You got it right. But rather than have the viewer risk their retina by directly looking into the prism (and having to bend down), the rainbow projects onto a white placard so it's seen indirectly and safely (while standing comfortably). Where the placard is perpendicular to the projected light rays of the rainbow, the display is small but bright. In my case the placard is set at a bias so the displayed rainbow is spread out to appear larger but proportionally dimmer. Naturally the placard is in the shade so much dimming is acceptable. In my case, the mother-in-laws birth date (Nov 21) and earth position (Latitude appx 40 deg N) are convenient as far as required size proportions. The rectangular base, that supports the sun clock, is her calendar display device. The base works out to be appx 2.5 inch high, 8 inch wide East-to-West of which the hyperbolic aperature spans 5.5 inch of the South face, and 4.5 inch deep most of which is the distance between aperatures. It could be about an inch less in height but the proportions are pleasing and allot some height inside for a slanting "rain drain" and 3-point levelers. The heavy 16 gauge brass stock machining is being done "for free" by students at a local college. That stuff is for parts of the sun clock: base plate, upper and lower plates of the time arc, and two graceful pylon plates that support the time arc and gnomon bearings at the "precise angles" upon the base plate. I'm doing the brass tubing work of the sun clock: gnomon with slits, gnomon bearings, and telescoping "innards" for gnomon season mask and rotation limiting keys. I'm doing the printed circuit board stock stuff which is the base/calendar display. I'll acid etch the motto "Let there be light" in the base plate when it gets back from the college. I haven't found anyone yet to: engrave the gnomon (curved surface engravers are rare), engrave the 2-ply white-over-black plastic insert that rotates just a bit inside the time arc so that hour numerals change between STANDARD and DAYLIGHT as seen through holes in the time arc, plate the exterior sun clock pieces with gold. Must find an engraver soon for the gnomon because I have to solder all the brass parts together (no screws) before gold-plating. The plating sequence is: copper, nickle, gold. I can do copper plate myself - easy. I'm willing to do nickle plate (never did it before). But gold plate means deadly fumes - either cyanide or arsenic - whatta choice! Jewlers I've found to date don't have plating tanks large enough. Suprisingly, half the jewlers know little about underplate (copper & nickle) and most don't do purities above 10K. 14K is needed (assuming the other 10/24ths isn't junk metal) to hold up outdoors for 20 years. Found one outfit (in Georgia) that does 24K but I'm not sure my mother-in-law rate pure gold!