Hi Douglas and all, I can think of a couple of approaches off hand.
A multiple ridge dial with each ridge only an inch or so high, the 11 and 1 o'clock shadows determining where the next ridge would go, the 10 and 2 o'clock the next, etc. All the ridges pointing north and south of course. 15 degree steps at the equator all year around I believe. The ridges could be square topped, or, with a little work, round topped. Another approach would be to have a heavy grate over a sundial surface with a distinctive mark on the grate to cast the shadow. If there were crossing telephone wires maybe a bifilar dial could work, or even a polar dial with a high wire gnomon. If none of these would work, ask me again. Date sent: Sun, 18 Jan 2004 18:54:45 GMT From: Douglas Hunt <[EMAIL PROTECTED]> To: sundial@rrz.uni-koeln.de Subject: A 'gnomon-less' sundial for locations near the Equator ? Send reply to: sundial@rrz.uni-koeln.de > > Can any of our Mailing-List experts suggest some horizontal sundial design > suitable for locations almost on the Equator, (actually 2 Degrees North) ? > > We have been contacted by a school in Singapore, who would like to install > a large playground sundial - BUT ideally having nothing above ground-level > to cause any 'accidents', or increase the cost/complexity of their layout. > They want to avoid a 'gnomon' obstructing vehicles in the playground area. > > They had initially thought of using a traditional "analemmatic", but those > are not really suited to locations within the 'tropics' (because the Hour- > markers will interfere with the central Date-scale). We recommended using > a 'door-frame polar' design, as being the most popular for schools near to > the Equator (i.e., two upright supports with a near-horizontal North/South > cross-piece, the shadow of which tells time on Hour-lines painted on their > playground) - but they prefer an entire layout on the ground, if possible. > > I will be very grateful for any suggestions, as to whether there is a type > of sundial which could be installed at a near-Equator location - and which > does not need a 'gnomon' (apart from maybe a person!), above ground-level. > > Douglas Hunt. > > -- > > "MODERN SUNCLOCKS" - 'Human Sundials', using YOUR OWN SHADOW to tell time. > > Looking for a useful, decorative, yet UNIQUE feature ? - you've found it ! > For further details and photographs, see our Website at: www.sunclocks.com > > Mail Address: 1 Love Street, Kilwinning, Ayrshire, Scotland, KA13 7LQ, UK. > Tel & Fax (UK): 01294 552250. International Tel & Fax: + 44 1294 552250. > E-mails to: [EMAIL PROTECTED] OR [EMAIL PROTECTED] > - -
