NavList:

From: Geoffrey Kolbe <geoffreykolbe@compuserve.com>
Subject: [NavList] Finding longitude in the 12th century
To: NavList@fer3.com
Date: Thursday, August 30, 2012, 10:31 PM

There is a thread running on the History of Astronomy forum (HASTRO) started by Janie Schwab (schwab@DUDLEYOBSERVATORY.ORG) who relayed a request by a movie script writer. The script concerns an island in the Med where a fantastic treasure is buried. The whereabouts of this island was historically lost, but an artifact with the island's latitude and longitude written on it is discovered in the present day. The heros correct the error in the lat. long. by using a depiction of Orion on the artifact.

The discussion follows along the lines of finding the position of cities by the timing of lunar eclipses. But one contributer, Clyde Hostetter, says, "I spent some of WWII as a Navy officer, learning and using a system for determining a point's latitude and longitude using only sightings of stars. So did other navigators. The secret was volumes of WPA calculations which were used to convert the star sightings into an accurate-enough location that all Navy ships used...and will again use if the satellites all fail."

Does anyone here have any comments on this WPA method (whatever that was)?

Can anyone suggest a means of finding accurate longitude using methods available in the 12th century?

Is there a way of using a depiction of Orion to correct for an error in longitude?

Thanks

Geoffrey