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Author
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Topic: GMT vs UT
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SMadden
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posted February 12, 2006 10:00 AM
I'm curious about the difference between Universal time and GMT. Is
there really a difference? What exactly is this difference?
From: Greeley
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David Burch
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posted February 12, 2006 12:11 PM
The short answer is these two things are identical, or at least used identically in navigation. That is, a navigator could refer to the time he cares about as GMT or UT. Many official reference books now write it as simply "UT," whereas they started out at "GMT", then "UT(GMT)", and now "UT". Other agencies refer to this time as UTC
But there is a longer answer, which is in our cel nav glossary in the back of the course materials, or in the glossary tab of the online course presentation. GMT is actually a special form of UT called UTC, etc...
This is an equally important terminology question in meteorology, where weather maps and forecasts must be labeled with a time.
I will look for our discussions of that and if this does not cover what i think it does, we will come back here and fill it in.
We are among those who choose to hang on to the term GMT for a bit longer, but my guess is in another year or two it will be gone. UT has been the "official" name for many years now... but there are several types of UT, etc... see glossary
Here is an excellent "portal" to relavent references: http://www.time.gov/about.html
We also have an excellent discussion of the topic in the ISSUE #91 of the Navigator's Newsletter.
From: Starpath, Seattle, WA
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