Sarah, I have not used a sun-compass myself but your picture looks very like the Universal Sun-compass fitted to British army vehicles for desert operations and which is intended to be used with the plate horizontal. A good description of the use of this device can be found in the Journal of the Institute of Navigation, Vol 6, p 184(1953). The article is entitled 'Navigating Ashore' by Brigadier R A Bagnold FRS. Brigadier Bagnold describes its use as follows:
"The time of day is marked on a set of ellipses, one for each latitude, on an upper plate, and a radial arm is set every quarter of an hour or half hour to the appropriate time. The Sun's shadow is kept on this arm so that the centre line of the upper plate always lies on the meridian. Changes in the Sun's declination are adjusted for by sliding the whole upper plate to and fro along the meridian in relation to the central style. Below this is the compass plate, graduated to 360 degrees in the reverse sense. This plate is fixed permanently on the fore-and-aft axis of the vehicle and the upper plate is set to the required course to be followed." Geoff Thurston 51.31N 00.91W -----Original Message----- From: Sarah Edmondson-Jones [SMTP:[EMAIL PROTECTED] Sent: Thursday, November 09, 2000 6:27 PM To: [email protected] Subject: suncompass Hello All, Is anyone out there familiar with the sun compass fitted to SAS military Landrovers? A friend who is considering buying one spotted the attached picture in a Landrover magazine. I found one or two websites selling horizontal sun compasses, but I would like to know more about the design, function and origins of this one. best wishes Sarah << File: ATT00000.htm >> << File: suncompass (4).jpg >>
