Ecliptic Time

Ecliptic Time is a system for dividing the time of day in a natural and beautiful way. It may also be viewed as a revolt against the artificial aspects of standardized time zones and especially against Daylight Saving Time (or Summer Time).

In this system, each day is divided into twelve parts, called dihours, and each part is divided into thirty sunsteps. Dividing the day similarly to how the year is divided into months and days is apparently the motivation behind the twelve hours of light and of darkness, but the originators made a crucial error in the construction. (They did not understand that light and darkness were parts of one, more important, whole.) The current system corrects this problem and produces the system “that always should have been”.


Dihours (Latin: Dihorae) last two conventional hours long (hence its name). The first dihour begins at 6:00 a.m. Apparent Solar Time (Apparent Solar Time is pure, sundial time.) The dihours then have beautiful names, as follows:
01 Early Morning (begins 6:00 a.m. A.S.T.)
02 Mid Morning (begins 8:00 a.m. A.S.T.)
03 Late Morning (begins 10:00 a.m. A.S.T.)
04 Early Afternoon (begins 12:00 noon, A.S.T.)
05 Mid Afternoon (begins 2:00 p.m. A.S.T.)
06 Late Afternoon (begins 4:00 p.m. A.S.T.)
07 Early Evening (begins 6:00 p.m. A.S.T.)
08 Mid Evening (begins 8:00 p.m. A.S.T.)
09 Late Evening (begins 6:00 p.m. A.S.T.)
10 Early Aftermidnight (begins 12:00 midnight, A.S.T.)
11 Mid Aftermidnight (begins 2:00 a.m. A.S.T.)
12 Late Aftermidnight (begins 4:00 a.m. A.S.T.) *


Sunsteps (Latin: Solisgradus) are the time it takes the Sun to move one degree of arc across the sky.** There are thirty sunsteps in each dihour, and each sunstep lasts four conventional minutes long.*** Like everything else in the Ecliptic Calendar, sunsteps are numbered ordinally, starting at 1 not 0.

To compute the quantities mentioned, use the spreadsheet found on the page “The Calendar Itself”.

Notice that one starts one's days in the morning, not in the dead of night, in this system. The sequence of quarters of a day, Morning, Afternoon, Evening, and Aftermidnight mirrors in microcosm the seasons of the year, Spring, Summer, Autumn, and Winter. One also is normally awake rather than asleep to see each day begin.

Furthermore, an armillary sundial can easily be constructed to read time to within four minutes (that is, one sunstep). Because of the use of Apparent Solar Time throughout the definition, such a sundial would read Ecliptic Time directly, without fretting over adding or subtracting the Equation of Time or doing Time-Zone offsets or messing with Daylight Saving Time (Summer Time). In all, one's sense of time is always in perfect accord with the position of the Sun— for many people the way it always should have been, and can be now for anyone who wishes to adopt the Ecliptic system.

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* In the summer months, the sun rises in this interval of time and in this circumstance the dihour may be numbered 00 of the day following and be given the name “Very Early Morning”.

** Actually, it is the foot of the perpendicular from the center of the sun to the Celestial Equator that moves one degree of arc with each sunstep. An armillary sundial will drop this perpendicular automatically.

*** Due to the subtleties of the analemma, sunsteps are actually a few hundredths of a second more or less than exactly four minutes. This tiny correction is computed as the first derivative of the Equation of Time. Similarly, a dihour differs by a fraction of a second from exactly two hours.