NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Silicon Sea zone time
From: Paul Hirose
Date: 2006 Jun 8, 20:58 -0700
From: Paul Hirose
Date: 2006 Jun 8, 20:58 -0700
Renee Mattie wrote: > > When navigating, do we ignore "political" time zones? Palma de Mallorca > "should be" in GMT+0, but uses CEST (GMT+1 hour). Silicon Sea, Leg 10 asks > for sunrise, zone time, on 11 May 1996. The answer key gives this as 0440 > ZT, while the USNO website says sunrise is at 0440 GMT/0540 CEST. I think the zone time offset from Greenwich should be stated as one of the input conditions of the problem. In the real world you would know. Even if you mistakenly believe Palma de Mallorca is on Greenwich time, sunrise will still occur at the predicted shipboard time, since as navigator you're the one who decides what time zone is in effect. The principle of treating zone time offset as a "known" should be extended to all the Silicon Sea problems. Asking what your DR position will be at a certain zone time can get tricky if the predicted position is near a zone boundary. I remember at least one case like that. If I were in charge, all the navigation aboard Silicon Sea would be done in Zulu time. -- I block messages with attachments or HTML.
