Hello Frans' You raise a good point on the determination of longitude. The answer is eclipses. The details were not included in the version presented at the conference. I have now added a few slides that were not uses as the text did not show well on the maps and the details were not necessary to communicate the story. The file has grown to 7.5 MB http://www3.telus.net/public/rtbailey/GodsLongitude/
These explorers had the right stuff. James Harriot, described as the best mathematician Oxford has produced, was employed by Raleigh as a navigator, astronomer and cartographer. His observations of a solar eclipse on 19 April 1585 on the voyage to Virginia have been used to determine the latitude and longitude of the ship. Many think that he was on the 1584 voyage as well and had hoped to observe a lunar eclipse in Virginia in November but the historical records show a earlier return in September to avoid the winter north atlantic storms. See http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Harriot.html The map John White pained was based on Harriot's accurate surveys in 1585/86. Is there documentary evidence that they accurately measured the longitude? No, but navigation was a state secret at that time, a strategic asset not to be shared with your enemies. Drake's voyage is an example of this secrecy. If they had a longitude fix, the data remains a secret. They certainly had the capability. Things have not changed much. Until recently the US military dithered the GPS system to protect strategic state secrets. Simon Cassidy responded with a few corrections. Omar Khayyam's 33 year cycle does not give you God's Longitude. The longitude depends on the start year and Khayyam would not have used a calendar based on the life of Christ. John Dee did. This is clear in his writing. Regards, Roger Bailey ----- Original Message ----- From: "Frans W. Maes" <[EMAIL PROTECTED]> To: "Roger Bailey" <[EMAIL PROTECTED]> Cc: "Sundial List" <[EMAIL PROTECTED]> Sent: Saturday, September 29, 2007 6:09 AM Subject: Re: God's Longitude and the Lost Colony of Virginia > Dear Roger, > > An intriguing story! Thank you for making this available to us all. > What I wondered about: how accurately could longitude be determined around > 1600? That problem was tackled only over a century later... > > Best regards, > Frans Maes > > Roger Bailey wrote: >> >> At the BSS meeting in Cambridge this spring. Frank King outlined the >> problems assigning a unique date to a mark on a sundial. With our >> Gregorian calendar and leap year cycle the date for any given solar >> declination can vary over four days. He showed how a calendar based on a >> 33 year cycle devised by Omar Khayyam could reduce this spread to 24 >> hours. He then pointed out that for one specific longitude, the date of >> the first day of spring would always be the same. He mentioned that this >> was called God's Longitude and left it for us to figure out where that >> was as a homework exercise. >> I've done my homework and discovered a remarkable story, one that just >> had to be told at the NASS Conference in Virginia, at the 400th >> anniversary of the Jamestown colony of 1607. Fred Sawyer agreed to work >> with me as co-author and to present at the conference the story of >> "God's Longitude and the Lost Colony of Virginia". It is a great story of >> the birth of science in Elizabethan England, the global conflicts of >> religion and empires and a secret agenda for the English protestants to >> occupy the new world at longitude 77ºW, God's Longitude. >> I have posted the presentation as Fred presented it at this personal >> website for you to download and enjoy. >> http://www3.telus.net/public/rtbailey/GodsLongitude/ It is a 5.7 MB >> PowerPoint presentation. If you do not have PowerPoint, download the free >> viewer from Microsoft. This will allow you to view the presentation but >> not the speakers notes that go alone with it. >> I would like to thank Frank King for the inspiration, Simon Cassidy for >> doing the historical research and uncovering the secret agenda, and >> Duncan Steel for publicizing it in his book "Marking Time: The Quest for >> the Perfect Calendar". >> Enjoy, >> Roger Bailey >> www.walkingshadow.info >> http://www.walkingshadow.info> >> ------------------------------------------------------------------------ >> >> --------------------------------------------------- >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> > --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
