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Astro*Dictionary by Michael Erlewine





6 articles for "Time"

Time [DeVore]

The measurement of time is inseparable from considerations of place, and of a point of reference. The establishing of the actual moment of an occurrence, and its statement in terms of Universal Time, is one of the most difficult problems with which the astrologer deals, because of the prevalent neglect on the part of those who make the record of the moment of an event, to qualify it by stating in what manner of time it is noted: whether apparent solar time, as shown on a sundial; mean time, as shown by a clock adjusted to the meridian of the place; local Standard Time, as shown by a clock adjusted to a Standard time meridian, and if so, which one; or whether in Daylight Saving Time, War Time, Double Summer Time; and so on.

Sidereal Time

That in which the point of reference is a star — as the most nearly fixed point in the universe as it appears from the Earth. Two successive crossings of a star is the measurement of a sidereal day, which is divided into 24 hours, beginning with oh and continuing to 23h 59m. It is used by astronomers, chiefly to express in hours and minutes of sidereal time the Midheaven longitude of a given place. Prior to 1925 0h of the astronomical day coincided with noon but in that year astronomical and civil time were made to coincide, since when oh has coincided with midnight.

Solar Time

That in which the point of reference is the Sun. This may be apparent Solar time, as shown by a sundial; or local Mean Time, as shown by a clock adjusted to an average rather than an actual day. This is explained more fully under Equation of Time (q.v.). With Solar Time, noon was approximately four minutes earlier or later with every increase of distance of 1° East or West of Greenwich Observatory, which at zero longitude is the point for which Universal or World Time is computed. Apparent and Mean Solar Time coincide four times a year: on April 15, June 14, Sept. 1 and Dec. 25. At all other times the Sun is fast or slow by from one to sixteen minutes.

Standard Time

Since the meeting of train schedules is impossible on the basis of local time, Standard time-zone meridians were spaced at intervals of 15° of longitude East and West of Greenwich, and all clocks within each zone were adjusted to the mean Solar time of the midpoint of the zone. Standard Time was generally adopted on Nov. 18, 1883, but it did not come into common use in some localities until after many years had elapsed. Even yet there are communities in which the time of day is given in Sun time; unless you wish to catch a train, in which case you are given Railway Time. Not only that, but longitude is becoming an increasingly unreliable guide, for some communities which are actually in the Central Standard Time zone run by Eastern Standard Time, to make their business day coincide with that of some nearby city across the meridian; and similarly at various points throughout the world. Lacking such exceptions, all places in the United States east of 82°39' W. Long. are theoretically in the Eastern Standard Time zone, and their time is 5h earlier than that of Greenwich; Central Standard Time, 6h earlier than Greenwich, applies to points between 82°30' and 97°30' W. Long.; Mountain Standard Time, 7h earlier than Greenwich, between 97°30' and 112°30' W. Long.; and Pacific Standard Time, 8h earlier than Greenwich, to all points in the United States west of Long. 112°30'. However, one need but observe on any time zone map the irregular lines which indicate the Time Zone meridians across the country, to realize how important it is that any statement of time of an event is incomplete and unreliable unless it carries with it a statement of the kind of time in which the event was recorded, and the standard meridian adopted by that community.

Daylight Saving Time

This was originated in England in 1916, where it was called Summer Time. It consists of an arbitrary setting ahead of the clock by one hour, thereby shifting all the day's activities an hour earlier, ending the work day that much sooner and leaving an hour more of daylight in which to indulge in seasonal recreations. In general, it commences at 2 A.M. of the Sunday following the third Saturday in April, and ends on the Sunday after the first Saturday in October. This is not a reliable guide, for in its earlier years it sometimes began as early as March 24. Furthermore, during World War II England set the clock ahead by two hours, making Double Summer Time. During the same period, beginning Feb. 9, 1942 at 2 P.M., the United States had War Time, a year-round setting ahead of the clock by one hour. Prior to that, some parts of the United States observed Daylight Saving Time during certain periods in certain years, but other localities refused to accept or ratify it; and even in those where it was legally authorized, many refused to abide by it. Even though a record of the vagaries of time observance is attempted in a volume called World Daylight Saving Time, by Curran and Taylor, the only safe way to record an event is not only to state in what kind of time it was recorded, but in addition to give its equivalent in Greenwich Standard or Universal Time. In most other countries the problem is still more complicated. All of Mexico is -6h, except part of Lower California, which is -8h. Some adopt a time meridian that involves a half-hour adjustment, like Hawaii, which is GMT -10h 30m. All of Russia adjusts to a time unit which is the virtual equivalent of permanent daylight saving. Bolivia is -4:33 and Venezuela -4:30. In addition, there is for some Middle European countries an adjustment of the date itself from the old-style to the new-style calendar, and the impossible determination whether time was given in apparent Sun time or Solar Mean time, or whether some arbitrarily selected meridian became the basis for the standard time of the country.


Among the Time zones most frequently to be encountered are the following:

[A list more modern than that originally appearing in DeVore follows. For each time zone, the name is followed by abbreviations for standard, daylight, and war times, followed by the longitudinal difference from the zero meridian at Greenwich England, followed by the separation in hours from +0 Greenwhich.]


TIME ZONEAbbreviationsLongitudinal
in Hours
USSR ZONE 10Z11,11D,11W-165-11


[Here is the original DeVore list.]

International Date Line EastIDLE+12h
International Date Line WestIDLW-12h
New Zealand Time NZT+11h30m
Guam Standard TimeGST+10h
South Australia Standard TimeSAST+ 9h30m
Japan Standard TimeJST+ 9h
China Coast TimeCCT+ 8h
Java TimeJT+ 7h30m
South Sumatra TimeSST+ 7h
North Sumatra TimeNST+ 6h30m
Indian Standard TimeIST+ 5h30m
Baghdad Time BT+ 3h
Eastern European TimeEET+ 2h
Middle Europe TimeMET+ 1h
Central European TimeCET+ 1h
Western Europe Time WET(coincides with GST)
West Africa TimeWAT+ 1h
Azores TimeAT- 2h
Brazil Standard TimeBST- 3h
Atlantic Standard TimeAST- 4h
Eastern Standard TimeEST- 5h
Central Standard TimeCST- 6h
Pacific Standard TimePST- 8h
Yukon Standard TimeYST- 9h
Central Alaska TimeCAT-10h
Hawaiian Standard TimeHST-10h30m
Nome Time NT-11h


The important factors for the astrologer to establish are: (1) the exact equivalent of a given moment as expressed in Universal Time, in order therefrom to compute from the Ephemeris the exact position occupied by the planets at that precise moment; and (2) the exact equivalent of the same moment in Local Mean Time for the place where the event occurred, wherefrom with the aid of the sidereal time of noon or midnight on that date, and of Tables of Houses for the Latitude of the place, to calculate the Midheaven position, the Ascendant degree, and the intermediate cusps of the Figure. Universal Time is variously called World Time, Greenwich Civil Time, Greenwich Standard Time, or zero zone time.

An ephemeris calculated for other than zero meridian is a simplification that is of doubtful value, in that it introduces the possibility of confusion on the part of those who work by formulas rather than by a comprehension of the elements involved. In using an ephemeris calculated, let us say, for 75° W. Long., one bases his calculations on that time meridian, instead of the zero meridian, correcting zone time to local time by subtracting 4m for each degree of longitude W., or adding it for each degree of Long. E., of the 75th meridian.

Army and Navy Time

Just as the Navy has long since abandoned the traditional method of "boxing the compass" and instead indicates direction in degrees from 1 to 360, so both Army and Navy have abandoned the twelve-hour clock in favor of the 24-hour clock, which begins at midnight as 00 00h, is 1200 at noon, 1330h at half-past-one, and so on until 2359h, which is one minute before oh of the next day. Thus A.M. and P.M. become no longer necessary in connection with the time of day or night. The public will be slow to demand 24-hour clocks and watches, but indications and efficiency point to the probability of their eventual general use.

Recording a Birth Moment

Never make record of or state a birth hour as midnight, for the day both begins and ends with midnight, and in time you yourself will not know which it was — resulting in a tiny difference of twenty-four hours. The day begins with 0h; noon is 12h. A minute before midnight can be 11:59 P.M., or 23:59h — but midnight is oh of the next day.

See also:
♦ Apparent Sidereal Time ♦ Apparent Solar Time ♦ Astronomical Time ♦ Civil Time ♦ Daylight Savings Time ♦ Double Summer Time ♦ Ephemeris Time ♦ Greenwich Civil Time ♦ Greenwich Local Time ♦ Greenwich Mean Time ♦ International Atomic Time ♦ Local Apparent Time ♦ Local Civil Time ♦ Local Mean Solar Time ♦ Local Sidereal Time ♦ Mean Sidereal Time ♦ Mean Solar Time ♦ Sidereal Time ♦ Solar ♦ Standard Time ♦ True Time ♦ True Local Time ♦ Universal Time ♦ Universal Coordinated Time
Time of Birth [Astro*Index]

The time on the Birth Certificate. This is generally observed as the first breath, and occurs a few moments after the cutting of the umbilical cord.

See also:
♦ Birth
Time Zone [Astro*Index]

A band of longitudes on the Earth, approximately 15° in width, wherein the same clock time is used. There are 24 of these, each progressively 1h more distant from the Greenwich meridian. In addition, the are several special time zones which are not located at integral multiples of 15° from Greenwich (thus, not at integral hours).

See also:
♦ Standard Time ♦ Clock Time ♦ Greenwich Meridian
Time Zone [Munkasey M.]

A band of area on the Earth, approximately 15 degrees of longitude wide, where the same clock time is kept. The time zones are referred to either by their names (e.g.: Eastern Time Zone, or Mountain Time Zone, etc.), or by letters of the alphabet. The Earth is divided into 24 such bands.

See also:
♦ Standard Time ♦ Clock Time ♦ Greenwich Meridian
Time, Equation of [Astro*Index]

This refers to the addition or subtraction used to convert apparent solar time into mean solar time. This must be done because the length of the day varies slightly according to season.

See also:
♦ Apparent Solar Time ♦ Mean Solar Time
Time Hits [Astro*Index]

A list of aspects formed over a period of time in relation to a transit or progression technique. This is a useful feature of many astrological computer programs.

See also:
♦ Aspect ♦ Transit ♦ Progressions


Astro*Index Copyright © 1997 Michael Erlewine


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