Science / Tides and Currents / Equation Of Time: Difference between mean and apparent time. From the beginning of the year until near the middle of April, mean time is ahead of apparent time, the difference reaching a maximum of about 15 minutes near the middle of February. From the middle of April to the middle of June, mean time is behind apparent time but the difference is less than 5 minutes. From the middle of June to the first part of September, mean time is again ahead of apparent time with maximum difference less than 7 minutes. From the first of September until the later part of December, mean time is again behind apparent time, the difference reaching a maximum of nearly17 minutes in the early part of November. The equation of time for each day in the year is given in the American Ephemeris and Nautical Almanac.
Science / Tides and Currents / Mean Time: Time based upon the hour angle of the mean sun as distinguished from apparent time which is based upon the position of the real Sun. The difference between apparent and mean time is known as the equat MORE
Science / Tides and Currents / Apparent Time: Time based upon the true position of the Sun as distinguished from mean time, which is measured by a fictitious Sun moving at a uniform rate. Apparent time is that shown by the sundial, and its noon i MORE