NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Ex-meridian sights -
From: Russell Sher
Date: 2001 Feb 13, 11:07 PM
From: Russell Sher
Date: 2001 Feb 13, 11:07 PM
Barrie - Your suggestion is in fact something that I have seen in a navigation examples book of mine. It is possible if the body is close to the observer's zenith around LAN to plot the circle of position (COP) from the altitude (since HO will be large and the COP radius small). Of course the altitude may be a bit too close to 90 degrees for a desirable observation. Then a LOP is taken just after (or could have been just before) this and the COP intersected with the LOP - assuming that the distance run between the two was insignificant. Perhaps someone has tried this. barry wrote... Most interesting. The Ex meridian method stems from ancient times before the good Marc. Ste. Hilaire position line method. However it appears to be time honoured especially with DOT examiners. What has always interested me is why not simply use a sight taken 10 or so minutes before or after noon ( up to 30 or so minutes allowed by ex-merid tables) as a simple P/L. It can be used with future or past P/L's to give a position. (snip...)
