I'd like to draw your attention to a star finder for sale on the Internet auction house eBay. See <http://cgi.ebay.co.uk/aw-cgi/eBayISAPI.dll?ViewItem&item=1077995691>
I own one of these, though I have to confess I haven't looked after it well and it is now missing some of the transparent overlays :-( I find it interesting that aircrew were issued with astrolabes, for that's what it is, during the Second World War. Strictly, perhaps, it isn't an astrolabe in that it has no alidade and no scales on the reverse, and the projection isn't stereographic. The instructions show how you can identify stars if you select and set the overlay corresponding to your Dead Reckoning (calculated/assumed) position. They don't tell you how to improve on dead reckoning by observing the stars' actual positions, but that must surely have been the intent. Chris Lusby Taylor 51.3N, 1.4W -
