Simple Simon wrote:
That's it but you need tables. You need tables because you measure
zenith and local hour angle.

To find longitude? If so, how's that done? I just put together a little
spreadsheet which seems to find longitude for zenith at any given GMT time.

06:00 gives -90 (90 deg east)
18:00 gives 90W
17:21:50 puts me very close to your meridian - 80d 27.5'W


--
Wally
www.art-gallery.myby.co.uk
Latest work: The Langlois Bridge (after Van Gogh)