NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Lunar parallax killed Amelia Earhart
From: Paul Hirose
Date: 2006 May 16, 19:20 -0700
From: Paul Hirose
Date: 2006 May 16, 19:20 -0700
This web page speculates that Amelia Earhart and Fred Noonan missed Howland Island because Noonan failed to correct for parallax when he shot the Moon: http://www.bbc.co.uk/dna/h2g2/A3694854 On the other hand, engineer Fredrick Hooven wrote that Earhart's decision to utilize a lighter and less sophisticated radio direction finder was probably a fatal mistake: http://www.tighar.org/Projects/Earhart/Documents/Hooven_Report/HoovenReport.html "Unfortunately the direction finder was unable to tell which direction to turn to go toward Howland due to the ambiguity of its loop signal." However, temporarily changing course 90 degrees and watching the bearing drift aft would soon resolve the ambiguity. It's hard to believe Earhart and Noonan would not know that. For another point of view, the next article blames the Coast Guard cutter Itasca at Howland Island for 1) failing to transmit a beacon signal on 500 kHz, and 2) bungling the search when it became clear the plane was down. http://www.usni.org/NavalHistory/Articles00/nhriley.htm Point #1 looks shaky to me -- several times Earhart requested that Itasca take a bearing on her aircraft, but as far as I've seen, she made no request that a homing signal be transmitted on 500 kHz. Interestingly, Earhart planned to carry two navigators on her round the world flight: http://www.unmuseum.org/earhart.htm But due to a two month delay while damage from a takeoff accident was repaired, the other navigator had to drop out of the project. Later, he must have felt rather like that deck officer who got bumped off the Titanic crew right before sailing!