from Sokolov Website

1. Introduction

The purpose of this Specification is to establish a Calendar for the Republic of Terra that allows for counting, naming and identification of days and years in a way that:

• accurately follows the sacred astronomical cycles of our planet, tying our identification of days and years to our place in the cosmos;
• is consistent with mathematical principles and convenient for computer processing;
• is internally consistent and free of historical idiosyncrasies;
• uses a time reference point that was a real event marking some very significant achievement for all humankind, rather than an invented zero point serving to underscore a particular doctrine;
• is suitable for both global and local applications;
• makes use of modern science and provides the level of accuracy meeting the strict time precision demands of modern electronic computer, communication and information processing systems;
• is based on sound mathematics and astronomy, rather than an edict of an authority figure from the dark ages.

2. Definitions

Local solar day

Period of time starting at midnight (lower culmination of the Sun) lasting until the next midnight. Can be established either by direct astronomical observation or by computation from UT and the time zone offset.

Mathematical day

86400 SI seconds.

MJD (Modified Julian Day)

As used in this Specification, an MJD is an integer identifying a day in a calendar-neutral manner. This Specification uses MJDs to identify local solar days, days of UT, and mathematical days of TAI. The specific mapping between days and integers assigned to them is historical and corresponds to that used by the Smithsonian Astrophysical Observatory (SAO) to track the first Soviet artificial satellite Sputnik.

Point of Ostara

The instant in the tropical year at which the Sun crosses the Earth’s equator from south to north. Note that the point of Ostara is an infinitesimal point in time, rather than a day or any other extended interval.

SI second

The duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.


Temps Atomique International (International Atomic Time), an international time standard that counts SI seconds with the highest accuracy possible with current technology, independent of any astronomical cycle or calendar.

Tropical year

A complete cycle of seasons caused by Earth’s obliquity and manifested in the point at which sunlight strikes the Earth at a right angle moving between the tropics.


Universal Time, the generic term for time systems anchored to Earth’s rotation and solar days, using the Greenwich meridian as the reference point. Also called GMT (Greenwich Mean Time).


An attempt, codified by international standards, to reconcile TAI with UT. In its present form defined by CCIR Recommendation 460 and its successors, it is a scheme that gives an alternate name to each TAI second that is (almost) usable as a form of UT.

UTCA (UTC Angle)

The turning angle of a dial clock synchronized to UTC expressed in seconds. UTCA is identical with UTC except around leap seconds.

3. Demarkation, counting and identification of years

3.1. Demarkation of years
Throughout the ages people have observed the passing of years by the cycle of seasons. Therefore, the common notion of a year corresponds to the astronomical definition of a tropical year given in Clause 2.

In the Republic of Terra Calendar a year shall mean a tropical year, and each new year shall be considered to begin at the point of Ostara.

3.2. Numbering of years
The Republic of Terra Calendar shall count years from man’s first trip into outer space on humankind’s own initiative and technology, i.e., the flight of Soviet cosmonaut Yuriy Gagarin. Years shall be identified by cardinal numbers. The year in which Gagarin’s flight took place (the 12th of April of 1961 by the calendar in effect in the Soviet Union at the time of the event) shall be called year 0 of Space Era.


(Since RT Calendar years begin at the point of Ostara, year 0 is the year that began on Ostara before Gagarin’s flight and ended on the following Ostara.)


The following year shall be called year 1 of Space Era, followed by year 2 and so forth. The year preceding year 0 of Space Era shall be called year -1 before Space Era. The year before it shall be called year -2 before Space Era and so forth.

3.2.1. Standard format for year numbers
The preferred way to write the number of year n of Space Era is SE n. The preferred way to write the number of year -n (before Space Era) is BSE n. However, since RT Calendar year numbers are ordinary integers, they can also be written as n and -n, respectively, where it is more convenient, e.g., in computations.

3.3. Reckoning of years
The Republic of Terra Calendar Keeper (see Annex A) shall announce the starting time of every RT Calendar year (point of Ostara) in seconds of International Atomic Time (TAI) via the Calendar Master File. Each year shall be defined to begin on a certain TAI second and last until the TAI second that starts the next year. TAI is used instead of UT or other time systems based on solar days since the cycle of tropical years is completely independent of other astronomical cycles, such as that of solar days, and thus should be reckoned by absolute time. The length of each year is thus an integral number of seconds, rather than days.

The Republic of Terra Calendar Keeper is responsible for announcing the starting time of every year at least 180 days in advance. The Calendar Keeper should strive for one SI second precision, i.e., within one SI second of the actual astronomical point of Ostara, but the minimum required precision is that the error does not exceed 120 SI seconds.

Since year lengths are measured in seconds rather than days and the start of each year is anchored to actual astronomical observation, no leap year scheme is used or needed.

3.3.1. Calendar Master File
The Calendar Master File (CMF) shall be produced and published by the Republic of Terra Calendar Keeper and shall indicate the TAI start time of every RT Calendar year. Annex B specifies the format of CMFs and other calendar data files.

The RT Calendar Keeper is required to publish a Calendar Master File or a set of CMFs covering all years from SE 0 through the present, as well as the next year if it is expected to begin in 180 days or less.

The RT Calendar Keeper may publish proleptic calendar data files for some periods before Space Era, but is not required to. Such files will generally be produced by historians to aid in the conversion of historical dates to the RT Calendar. The Republic of Terra Calendar Keeper’s Office shall provide an online electronic repository for these files so that once a correct proleptic calendar data file has been created for some period by some historian, this work will never need to be duplicated by others.

3.3.2. Corrections to CMF data
If a previously published starting time of a year prior to SE 44 is found to be in error, it may always be amended by publishing a corrected CMF. For years from SE 44 onward, once a year has started, the starting time published for it by the RT Calendar Keeper becomes the official starting time of that year for civil purposes, even if it is not astronomically exact.

CMF data for years that have not yet started are predictions. These predictions may be changed in favour of more accurate ones until 180 days prior to the start of the new year. After that point the published time becomes final and official for civil purposes as above.


4. Intercalation of days and years

One of the main functions of any calendar is to assign dates to days. The difference between a day and a date must be clearly understood. The term “day” commonly refers to a local solar day as defined in Clause 2, and that shall be the meaning of the word “day” in this Specification. A calendar date, however, identifies a certain point in the year, i.e., a certain point in the annual seasonal cycle and (approximately) in Earth’s orbit around the Sun (approximately rather than exactly due to precession of equinoxes). Days are local, but dates are global.

Since days and years are dictated by two different and completely independent astronomical cycles (Earth’s rotation for days and Earth’s orbit around the Sun and precession for years), it is meaningless to try divide the year into days, and days and dates do not exactly coincide. Rather than impose some arbitrary and ultimately unjustified scheme for dividing years into days, this Specification addresses the problem and specifies a standard approximation scheme for mapping days to dates that provides the highest possible accuracy, with the error never exceeding 12 hours.

4.1. Definition of dates
Each RT Calendar year shall be divided into mathematical days of 86400 SI seconds each (bearing no relation to solar days). Mathematical day of year (DOY) 0 shall begin at the point of Ostara. Since the length of one tropical year equals approximately 365.25 mathematical days, each RT Calendar year shall consist of 365 full DOYs and one short DOY.


DOYs shall be reckoned by TAI, rather than UTC or any other time system adjusted for Earth’s rotation, since DOYs are mathematical days of the year completely independent of local solar days and Earth rotation. Each DOY shall be assigned a date name as specified in Clause 5.

4.2. Mapping of local solar days to dates
Local solar days may be identified by calendar-neutral flat integers called MJDs. This subclause specifies the algorithm for mapping an MJD to an RT Calendar date. The mapping function is dependent on the time zone, thus a given date may be mapped to different MJDs in different time zones. (Note that since an MJD as used here identifies a local solar day and each time zone has its own local solar days, each time zone has its own MJDs.)

To establish the mapping the following procedure must be followed each year in each time zone:

1. Take the year starting time from the Calendar Master File.
2. Convert it from TAI to UT per UTC standard.
3. Convert from UT to local time by adding or subtracting the appropriate time zone offset. This step will yield the MJD and time of Ostara in the local time zone.
4. If the local time of Ostara is between 0:00:00 and 11:59:59, the local MJD on which Ostara falls shall be mapped to DOY 0 of the new year. If the local time of Ostara is between 12:00:00 and 23:59:59, DOY 0 of the new year shall be mapped to the next local MJD.

This algorithm guarantees that year dates and local solar days mapped to them will always overlap by at least 12 hours.

Once a given MJD in a given time zone has been mapped to DOY 0, succeeding MJDs shall be mapped to succeeding DOYs until next Ostara when an MJD is mapped to DOY 0 of the next year. 365 or 366 MJDs will be mapped in each time zone to a given RT Calendar year depending on the time zone and the times on which the two succeeding Ostara points fall. Since each RT Calendar year consists of 366 mathematical DOYs (the last one short), date names will be available for all these MJDs.

5. Naming of dates

Subclause 4.1 identifies 366 distinct dates in each RT Calendar year, numbered 0 through 365 as days of the year (DOY). This clause specifies names for these dates in the traditional month and day format.
The first 360 DOYs shall be divided into 12 months of 30 days each, similar to ancient Babylonian and French Revolutionary calendars.


The last 6 dates do not belong to any month and are identified only by their DOY numbers. In every locality (time zone) the last 5 or 6 days will be mapped to these dates. These days shall be holidays on which a pre-Ostara festival shall be held, and the corresponding dates shall be considered festival dates.

Months and days of each month shall be numbered from 0. Months may be given different names in different languages, but for international communication in ASCII two alternatives are specified: ASCIIfied ancient Akkadian and French Revolutionary calendar month names. While neither the ancient Mesopotamian nor the French Revolutionary calendar is identical with the Republic of Terra Calendar, their months are compatible since all calendars in question begin the first month of the year on an equinox (Ostara or Mabon).


Roman month names may not be used with the Republic of Terra Calendar, however, since Roman months do not correspond to RT Calendar months and trying to reuse Roman month names for completely different months would produce extreme confusion, but no useful gain.

The standard month names are:


ASCIIfied Akkadian
































































5.1. Standard date format
The standard format for writing Republic of Terra Calendar dates is:

<year> Mon dd

where <year> is the year in the preferred notation of paragraph 3.2.1, Mon is the three-letter abbreviation for the month and dd is the day number in decimal. For example, day 3 of Thermidor of year 42 of Space Era shall be written as:

SE 42 Thr 3

For festival dates the three-letter month abbreviation shall be Fes and the day number shall be DOY-360.

6. Practical applications

6.1. Local applications

6.1.1. Operation of clocks
It is expected that most clocks and other devices and systems that display time and date will continue to show the current local time and corresponding date as they did prior to the adoption of this new Calendar. Those devices that can only display time and not the date will require no modification. Devices that track or display dates will need to be changed to the new Calendar and date format.

The Republic of Terra Calendar is more complex than most previous calendars in that the mapping from an MJD to a date is not a fixed formula, but depends on the actual astronomical observation of Ostara published via the Calendar Master File and on the time zone. Most clocks are set manually by their human users and have no connection to global communication networks for time synchronisation.


The new Calendar’s complexities will not present any great difficulties for such clocks since their users can simply set the correct date. Since RT Calendar uses no leap year scheme, those clocks won’t be able to decide automatically whether to jump to DOY 0 of the next year after DOY 364 or 365, but needing manual attention once a year should not be an unreasonable burden.

6.1.2. Printing of wall calendars
Since the mapping between MJDs, from which the days of the week are derived, and RT Calendar dates differs with the time zone, different versions of wall calendars will need to be printed for different time zones. However, since there are only two possible MJDs to which day 0 of each year can be mapped, only two versions of the wall calendar will need to be printed each year, each serving one half of the world’s time zones.


(More versions may be printed, though, if other time zone-dependent information is included, such as exact times of various astronomical phenomena.)

6.2. Time signal distribution services
Point of Ostara information from the Republic of Terra Calendar Master File should be distributed by time signal services similar to how TAI, UTC and leap second information are distributed now. With this information radio-synchronized clocks can be built that always display accurate RT Calendar date and time; their firmware will need to implement algorithms prescribed in this Specification.

6.3. Computer clocks
It is expected that simple computer clocks will be free-running and will need to be set to the correct date and time by their users as described in subclause 6.1. More advanced computer systems will be more likely to have highly accurate clocks synchronised with TAI or UTC over communication networks, and store local copies of the Calendar Master File in their file system, updated over networks.


With proper configuration such systems will be able to compute the correct Republic of Terra Calendar date and time for any time zone by implementing algorithms prescribed in this Specification.

6.4. Global applications

6.4.1. Recording of important dates
There exists an obvious need to record the dates of major events that have global and lasting significance, such as birthdays, marriages, signing of treaties and declarations and major accomplishments. The date recorded for each such event shall be the true global date on which the event happened, in the definition of subclause 4.1, rather than the date mapped to the local solar day (as would be displayed on a wall calendar).

One difficulty arises in how would people know the correct global date if all wall clocks and calendars are synchronized with local solar days rather than global dates. The solution lies in informing people of the exact difference between local solar days in their locality and global dates, based on the algorithm specified in subclause 4.2.


Computer systems with advanced time keeping functions shall have a capability to display the exact overlap between local solar days and global dates in a message such as “global date equals local calendar date from midnight until 15:47:32; after 15:47:32 increment the local date by one to obtain the global date” or “global date equals local calendar date from 6:39:13 until midnight; before 6:39:13 decrement the local date by one to obtain the global date”.


If less sophisticated wall clocks are used, this information may be printed or written on a piece of paper placed next to the clock.

6.4.2. Global date-time specifications
In environments such as international radio and Internet communications or flight operations there is a need for precise and unambiguous date-time specifications valid on the entire globe.


This paragraph prescribes the form of Republic of Terra Global Date-Time (RTGDT) specifications to be used for such applications in the Republic of Terra. The RTGDT time shall be UTCA (defined in Clause 2) and the semantics of the RTGDT date are given below.

The RTGDT date is almost the same as the true global date (in the definition of subclause 4.1) except that it is reckoned by UTCA rather than TAI. Specifically, the starting time of the year from the Calendar Master File is converted from TAI to UTCA, and each RTGDT DOY from Nis 0 onward corresponds to 86400 seconds of UTCA.


The RTGDT date will almost always be exactly equal to the true global date except when the day boundary is off by a second or two because of leap seconds introduced during the year.

7. Conversion from other calendars to RT Calendar

7.1. Conversion of local dates
To convert a local date from another calendar to the RT Calendar, first convert it to MJD by the other calendar’s formula or algorithm and then convert the MJD to the RT Calendar date by the mapping prescribed in subclause 4.2.

7.2. Conversion of global dates
Dates of historical events of global and lasting significance shall be converted to RT Calendar global dates as described in subclause 4.1 and paragraph 6.4.1. Since all previous calendars had the local solar day rather than the global year as their fundamental unit, the conversion requires additional information beyond the date in the old calendar, namely the time and the time zone.

The conversion consists of fixing the moment in time when the historical event happened and determining what global date it would have fallen on if the RT Calendar were in effect then. The following algorithm or functional equivalent shall be used:

1. Convert the old date to MJD by the old calendar’s formula or algorithm. This step will yield the local MJD and time of the event.
2. Convert the local MJD and time specification to UT by adding or subtracting the appropriate time zone offset (make sure to use the offset in effect at the time of the historical event).
3. Convert to TAI if possible (see Annex D).
4. Convert to RT Calendar year and time within the year via the Calendar Master File.
5. Divide the time within the year by 86400 seconds. The integer quotient will be the date of the event in DOY form.

8. Other specifications

8.1. Daylight saving time
Use of daylight saving time in the Republic of Terra is prohibited by this Specification. The mapping of local solar days to global dates depends on each time zone’s UT offset, which must remain constant.


If adjustment is desired to make more efficient use of sunlight and reduce the need for artificial lighting, work schedules may be adjusted instead of changing clocks.

8.2. Numerology
Practice of numerology on Republic of Terra Calendar dates is strictly and expressly prohibited by this Specification. The numbers of years, months and days are objective, scientifically based mathematical statements about the identity of a given year, month or day, and do not carry any other associations.

Annex A (normative)

Republic of Terra Calendar Keeper’s Office

The Republic of Terra shall have an Office of the Calendar Keeper. The RT Calendar Keeper shall be a High Priest trained and competent in astronomy, mathematics and computer science. The Calendar Keeper shall be responsible for watching our planet’s astronomical cycles and ensuring that our Calendar accurately matches the sacred cycles of nature and our place in the cosmos.

The Calendar Keeper shall determine the official precise time of the point of Ostara and publish it via the Calendar Master File as described in subclause 3.3.

Annex B (normative)

Calendar data file format

This Annex defines the format of Calendar Master Files and other data files giving the times of significant astronomical or calendrical instants.

A calendar data file is a machine-readable ASCII text file containing time point definitions. Each line in a calendar data file is either a time point definition or a comment line. A comment line is an empty line, a line consisting entirely of white space, or a line beginning with a semicolon (‘;’).

Each time point definition has the following format:

<year> <point> <time>

<year> is the RT Calendar year number in the format recommended by paragraph 3.2.1.


<point> is a keyword (case-insensitive) identifying the point in the year that is being described:

START Beginning of the year (point of Ostara)
SUMMER Beginning of astronomical summer
AUTUMN Beginning of astronomical autumn
WINTER Beginning of astronomical winter

Other keywords may be defined in the future, either in future revisions of this Specification or in other specifications, therefore programs parsing calendar data files must be prepared to deal with unknown time point definitions.

<time> gives the time of the instant being described in TAI or UT with one second precision. A TAI <time> has the format:

A UT <time> has the format:

where mjd, hh, mm and ss are all decimal integers. hh, mm and ss shall be written with 2 digits each, no restriction is imposed on the number of digits for mjd.


Annex C (informative)

Meaning of TAI MJD

Normal MJDs are local solar days and are timed by Earth’s rotation. TAI MJDs, however, are mathematical days. TAI is independent of Earth’s rotation and local solar days, and TAI MJDs are merely a notational convenience.


Since TAI is an absolute time system not anchored to any astronomical cycle, it is difficult to establish a reference point for it. When TAI was adopted as a standard, it was chosen to express it in the form of days, hours, minutes and seconds like ordinary time based on local solar days, with the understanding that TAI days are in fact mathematical days rather than local solar days.

The TAI reference point was defined at MJD 36204 (January 1, 1958 by the calendar in effect at the time), namely TAI MJD 36204 was defined to coincide with UT MJD 36204.


Annex D (normative)

Proleptic use of RT Calendar before TAI

This Specification is specifically intended so that the Republic of Terra Calendar may be used not only in the present and future, but also proleptically to date events that happened long before its introduction. However, this Specification stipulates the use of TAI for demarkation of years and dates, and TAI is only defined back to MJD 36204 (in late BSE 4).

Rather than invent a “proleptic TAI” that would have very little other use, it is permitted to use other time systems, such as UT or Ephemeris Time (ET), instead of TAI for years before Space Era.


Annex E (informative)

Specification revision history

Revision Date Author Notes

1.0 SE 43 Add 28 Michael Sokolov Original version.
2.0 SE 44 Ulu 3 Michael Sokolov Changed the way the RT Calendar is used with UTC (par. 6.4.2), specified how to use the Calendar before TAI, added subcl. 8.2, and minor changes.
2.1 SE 44 Ulu 19 Michael Sokolov Clarified our definition of MJD, minor language changes throughout the spec for more correct use of the term UTC, added UTCA.