Greenwich mean time (GMT) or universal time (UT) is the mean solar time on the Greenwich meridian reckoned in days of 24 mean solar hours written as 00
h at midnight and 12
h at noon. To convert the above times to those of the other standard time meridians, add 1 hour for each 15
o of east longitude of the desired meridian and subtract 1 hour for each 15
o of west longitude. This table was compiled from data supplied by the
Nautical Almanac Office, United States Naval Observatory.