Forum Moderators: not2easy
I wonder how to call the reference time. When I was young the whole world knew what GMT (Greenwich Mean Time) meant, but now I wonder whether UT (Universal Time) or UTC (Universal Time Coordinated, I believe) would be more appropriate?
Minor problem, but advice would be much appreciated!
GMT and UTC are almost the same for most practical purposes:
[apparent-wind.com...]
I suggest you use the letters GMT or UTC depending on which you think your users would find clearest.
I suggest you use the letters GMT or UTC depending on which you think your users would find clearest.
Alas, that is precisely my question: Which would users find clearest? Or, to ask an admittedly different question: Which is most commonly used when addressing mixed international audiences?
The traditionalist part of me leans towards GMT, the with-it standards-knowledgeable part leans towards UTC. As a whole I am confused (as if you had not already figured that out).
UTC = French for "Coordinated Universal Time", as announced by station WWV (and WWVH) when I last heard them on shortwave. Oldies still call it GMT and young ones have usually never heard of the concept, never mind the labels.
At least, the military still uses z (zulu) (each longitude has its own letter)
Alas, that is precisely my question: Which would users find clearest? Or, to ask an admittedly different question: Which is most commonly used when addressing mixed international audiences?
WMW uses UTC. At least in does for me. Maybe there's a setting for that somewhere.
I have a site for technical people with an international audience. It also uses UTC.
Which is best would depend on your particular audience. Perhaps start with UTC and see who complains.
I should have figured that out myself since, while fooling around with the Google API, I had written a program to send two queries to Google and return the number of hits for each. Sort of like the Google Smackdown described in the Google Hacks book.
well, these results show that the historical term "GMT" is still widely used. However, it is obsolete and dating back to old days prior to the definition of UTC.
More reading: [aa.usno.navy.mil...] and [apparent-wind.com...]
If you don't want to drop the "GMT" term, how about stating the time as "... UTC (GMT)"?
Regards,
R.
Thanks for the URLs, but neither answers my real question.
Clearly astronomers use UT and its various derivatives, and if I were writing an astronomical treatise I would have no doubt which term to use. But what term do people looking at a schedule use? Is UT (or UTC) widely used outside the techical fields?
Here is an interesting item I just found, it is from the "Directive of the European Parliament and of the Council on summer-time arrangements" (title slightly shortened!):
Article 2
From 2002 onwards, the summer-time period shall begin, in every Member State, at 1.00 a.m., Greenwich Mean Time, on the last Sunday in March.
For my site that seems like a huge vote in favor of GMT.
For my site that seems like a huge vote in favor of GMT.
A vote by the EU Parliament only means a member country has a vested interest and has managed to convince the others to vote likewise. Similarly, a count of feet versus metres/meters on Google is not a meaningful test -- nearly 30 years after metrication here, we can't shake off people who use imperial measures in public and get the metric measures scrambled - klms, mtrs, kmph etc...
If the US East Coast is your primary audience, then a good starting point is what the NIST says:
http*//physics.nist.gov/News/Releases/questions.html
Is Coordinated Universal Time or UTC the same thing as Greenwich Mean Time?
Greenwich Mean Time is a 24-hour astronomical time system based on the local time at Greenwich, England. GMT can be considered equivalent to Coordinated Universal Time (known as UTC) when fractions of a second are not important. However, by international agreement, the term UTC is recommended for all general timekeeping applications and use of the term GMT is discouraged.
I have a table of the times of the Winter Solstice and Spring Equinox over the years. Initially I gave the times in US EST, as that is the main audience for my site. But recently I have noticed users from all over the world finding that page, and I decided to give a similar table in "international time".
Why not display times in both EST and UTC? Most people in the US will find EST much easier to use (even those in the other time zones are used to converting from ETC) and UTC will be more easily used by those in the rest of the world, as well as astronomers and others who usually work in UTC.
