Earth's orbit is an epicycle, which while pursuing its own orbit is carried forward in the larger
orbit of the Sun. The Moon's orbit is an epicycle upon the orbit of the Earth around the Sun. The
Sun, which is never retrograde, was the only solar system body which, according to Ptolemy, did
not have an epicycle.
Epoch. A point of time with reference to which other dates are calculated. Prenatal Epoch
applies to a system of rectification in which the Moon's place ten lunar months previous to
the birth moment becames the ascending or descending degree at the moment of birth. v.
Rectification.Equal Power, Signs of. v. Beholding Signs.Equation of Time. (1) Astron. The difference between mean solar time and apparent solar time.
The moment the Sun is exactly on the Midheaven of any place is apparent noon at that place;
hence an apparent solar day is the interval between two consecutive passages of the Sun across
the Midheaven, or the elapsed time from one apparent noon to the next. However, since the Sun
- or more correctly speaking, the Earth - does not move at a uniform speed throughout its orbit,
the length of the apparent day varies at different times of the year. To make possible the use of
time-keeping mechanisms, there was adopted a standard fixed day of 24 hours, known as a mean
day - the length of which is the average of all the apparent days of the year. The result is that
mean noon is sometimes earlier and sometimes later than apparent noon. The difference between
mean and apparent noon on any particular day, the Equation of Time, may amount to as much as
sixteen minutes. (2) Astrol. It is generally considered that in a Figure erected for noon the Sun
will be at the cusp of the Tenth House. This is approximately true, although at certain times of
the year it will be two or three degrees removed, on one side or the other from the Midheaven.
One sometimes hears the suggestion that the Figure should be erected by the Sun and not by the
clock, which would involve the application of the Equation of Time as a correction of clock
time. This is done when calculating the time of the rising of the Sun or other bodies. Its
application to the erecting of the Figure, however, would be utterly unsound, for the time in
which the birth is stated and the ephemerides which give the planets' places are both based on
mean time. If the Figure were to be erected for apparent time, the birth moment would have to
be corrected to apparent time, and the result would be the same. (3) It is unfortunate that this
term is incorrectly applied by some authorities to the difference between mean and sidereal time,
more properly termed the correction employed in reducing to sidereal time the elapsed mean
time of a given birth moment before or after noon or midnight. (4) The term has frequently been
incorrectly applied to the time equivalent of an Arc of Direction, in years, months and days - of
which few points in Astrology have been more debated. The coordination of the 360° of the
Equational circle and the 365¼-day year yields a mean value of 3m 56.33s per day, and a mean
increment of either Right Ascension or Longitude of 59'8". Some authorities advocate an
equation of 1° per year or 5' per month. Others advocate a method wherein the Arc of Direction
is added to the R.A. of the Sun at birth - the number of days after birth at which the Sun attains