NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Time
From: Jared Sherman
Date: 2004 Nov 9, 17:16 -0500
From: Jared Sherman
Date: 2004 Nov 9, 17:16 -0500
Doug, when you say "UTC and GMT denotes the same time zone of 0. One can convert daylight time to GMT and vica-versa without adding the step of getting standard time." Are you or aren't you saying that GMT and UTC are one and the same, and that neither one changes in any way for Savings Time? i.e. if NYC is at 15:30PM EDT (as it was today) which was also 20:30 GMT today, we are -5 hours from GMT today, but next June we would only be -4 hours from GMT? That's the crux of it, I'm being told that the relation to *GMT* both does and does not change as we get DST pulled over our eyes. I'm also being told that the relation to GMT does NOT change, it is only UTC that changes. ----- Original Message ----- From: "Royer, Doug"To: Sent: Tuesday, November 09, 2004 5:00 PM Subject: Time 11-09-04 20:42:00 UTC is the exact same as 11-09-04 20:42:00 GMT 11-09-04 03:42:00 PM EST is the exact same as 15:42:00 ZT During standard time(anywhere in the world) the zone time of an area is the time at the center of the zone. During daylight time(anywhere in the world)the zone time of an area is jumped to the next zone center to the EAST of the actual zone time of the area. ex: 120* 0' 0" W is the center longitude of zd + 8 during standard time. During dayligt time the center of that zone is now at 105* 0' 0" W or zd + 7. 120* lon./15 = 8 hrs. 105* lon /15 = 7 hrs. UTC and GMT denotes the same time zone of 0. One can convert daylight time to GMT and vica-versa without adding the step of getting standard time.Just remember the rule that the 1st Sun. of April at 00:00:00 zt roll the clock forward 1 hour to the next zone's center longitude and the last Sun. of Oct. at 00:00:00 zt roll the clock back 1 hour to the actual center longitude of the zone in question. This is also important when calculating tides in areas.