The Meridian Conference in 1884, attended by representatives from various countries, led to the creation of the 24 time zones we use today. Local Times Around the World - dateandtime.Increasing globalisation in the Victorian era meant a need to standardise time zones, as businesses began to operate across wider areas and world travel became easier with the advent of the railway.Precise Time - Naval Oceanography Portal.A Walk Through Time - National Institute of Standards and Technology.EST), you must subtract 5 hours from UT:įor more information on time reckoning and time zones, check out In order to convert any eclipse predictions from UT to local time (i.e. Once noted, use this number to convert all eclipse prediction times from UT to your own local time.įor example, if you are in the Eastern Standard Time zone, you will see that your local time is 5 hours earlier than UT. Master Clock to determine how many hours different your local time is from Universal Time. The official source of time used in the United States is the Time Service Department of the U.S. UTC is the time used by GPSs and is the standard reference for Time Zones around the world. Occasionally, a "leap second" is added to UTC in order keep it in sync with UT (which varies due to Earth's rotation). It is synchronized and adjusted to stay within 0.9 seconds of Universal Time (UT). You also need to know if Daylight Saving Time is practiced during that time of year.Ĭoordinated Universal Time (UTC) is based on atomic time. Time zones for countries around the world can be determined using the map above. World Time Zones (click to see larger image) So the local time in Toledo is 16:25 (=4:25pm). Toledo is in the Eastern Standard Time zone, so:īut since Toledo observes Daylight Saving Time in June, we must ADD one more hour to the standard time. If Daylight Saving Time is in effect in the time zone, you must ADD one hour to the standard time.įor example, let's assume that an eclipse begins in Toledo, Ohio on June 20 at 20:25 UT. Pacific Standard Time (PST) = UT - 8 hours Mountain Standard Time (MST) = UT - 7 hours In order to convert such predictions from UT to local time, you need to know what time zone you are in.įor North Americans, the conversion from UT to local time is as follows:Ītlantic Standard Time (AST) = UT - 4 hoursĮastern Standard Time (EST) = UT - 5 hoursĬentral Standard Time (CST) = UT - 6 hours Most astronomical predictions are usually presented in terms of Universal Time. It's also approximately equal to mean solar time from Greenwich.
Universal Time is actually based on the mean sidereal time as measured in Greenwich, England.
Universal Time (UT) is the precise measure of time used as the basis for all civil time-keeping.Īlthough their exact definitions differ, most readers can assume that Universal Time is equivalent to Greenwich Mean Time (GMT). Or we can measure time based on the rotation of Earth on its axis with respect to the stars (Universal Time).įinally, we can measure time through the oscillations of atoms (International Atomic Time). For instance, we can measure the passage of time via the orbital motion of Earth and other planets in the solar system (Dynamical Time). Time can be measured in a number of ways.
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