#Gmt 1 time zone manual

At first though, Greenwich time was only really important to astronomers. This was Greenwich Mean Time, or the average time when the Sun crossed the meridian at Greenwich. Here he had the best pendulum clocks installed and set them to the local time. Soon after, he was appointed as the first Astronomer Royal and moved into the new Royal Observatory in Greenwich.

John Flamsteed came up with the formula for converting solar time to mean time, and published a set of conversion tables in the early 1670s. It wasn’t until the invention of the pendulum clock in the 1650s that it was possible to work out the relationship between mean (clock) time and solar time. Greenwich Mean Time is also the name of the time zone used by some countries in Africa and Western Europe, including in Iceland all year round. Though it has now been replaced by Coordinated Universal Time (UTC), GMT is still the legal time in Britain in the winter, used by the Met Office, Royal Navy and BBC World Service. From 1884 until 1972, GMT was the international standard of civil time. GMT stands for Greenwich Mean Time, the local clock time at Greenwich. Today GMT is reckoned from one midnight to the next.įind out about the Prime Meridian What does GMT stand for? It’s a way of standardising and regularising time so we can all know exactly what time it is for our (or anyone’s) location. Solar time varies throughout the year, as the time interval between the Sun crossing a set meridian line changes.īut each day measured by a clock has the same length, equal to the average (mean) length of a solar day.

#Gmt 1 time zone manual

If you are going to do manual shifts rather than using your timezone database, at least use TZ=WET0 and TZ=WEST-1 so date will correctly show the Western European Time and Western European Summer Time abbreviations for current times.Essentially, mean time is clock time rather than solar (astronomical) time. If you haven't been installing updates to Solaris 10 from Oracle and you haven't manually updated your timezone database from the timezone database creators, I won't try to predict what will happen when daylight savings time shifts occur. (This also means that if you still choose to perform manual shifts to TZ, you need to reset TZ and reboot your system at exactly the times when when the daylight shifts occur.) (The TZ setting also affects the display of dates in other utilities like ls -l output and the ways dates and times are calculated by the touch utility.) Using any TZ rule that ignores the daylight savings time shifts will always incorrectly display a timestamps set during the opposite setting. The difference between TZ=GMT-1 and TZ=GMT+1 is two hours and neither of them will correctly show the timestamps on files both before and after the switch to or from daylignt savings times. I don't have access to a Solaris 10 system and won't try to predict what TZ=:GMT+1 or TZ=:Etc/GMT-1 will do. TZ=GMT-1 will interpret ALL times it encounters as 1 hour ahead of Greenwich and TZ=GMT+1 will interpret ALL times as 1 hour behind Greenwich time.

The whole idea behind having a database for Casablanca is that it should know the daylights savings time changes that have occurred at least since 1970 (and if you keep the database up-to-date) will also know about the most recent daylight savings start and stop time rules put in place by the Moroccan government (including the fact that daylight savings time is suspended during Ramadan in Morocco so Morocco has 4 timezone shifts per year while most of the United States and Europe have 2 timezone shifts per year). You should not change TZ=Africa/Casablanca to anything else.