# AAT ICAS 1200 ✧ Uniform Calendar (UC) specification

- general description
- specification of years
- specification of uniform months
- specification of days in a uniform month
- specification of uniform daygroups

## general description

Uniform Calendar (UC) methods for the specification of uniform months, uniform daygroups, and days integrate schemes from the Gregorian calendar with a number of uniform schemes. principles for the use of the Uniform Calendar can be applied to determine factors of calculation among other calendar systems. the UC scale is designated for use in ICAS with the New Calendar (NC) year scale.

## specification of years

Uniform Calendar years are specified in terms of a New Calendar year scale per the New Calendar specification AAT ICAS 1100. the system identifier term 'UC' may be used to designate the use of the Uniform Calendar for an ICAS date for which the era would be established.

eras in the New Calendar may be designated via the use of an era identifier term combined with the 'UC' system identifier term:

- UCN designates use of the Uniform Calendar for any New Calendar-era date: UCN 12003 (AD 2003).
- UCA designates use of the millennial-place digits of the uniform tenmillennium yeargroup NC 10000-19999 for coordination of Uniform Calendar years corresponding to the Gregorian calendar: Uniform Calendar year UCA 2003 corresponds to Gregorian calendar year AD 2003.

dates corresponding to the Julian Calendar can be expressed in terms of the UCN era, however those dates occurring in the tenmillennium yeargroup NC 10000-19999 (circa BC 1 to AD 9999) may also be expressed in terms of the UCA era.

the 'UC' system identifier may also be combined with other yeargroup terms that are designated in terms of localized term sets per ICAS.

## specification of uniform months

a Uniform Calendar year is comprised of twelve uniform months of 30 days, counting from the first day of a New Calendar year, with the remaining yearend days and any leap day grouped at yearend into the 12th uniform month.

uniform months of the Uniform Calendar may be designated in terms of localized term sets per ICAS.

## specification of days in a uniform month

a Uniform Calendar date begins at t000 midnight and ends at the conclusion of t999 prior to the next day's midnight. please see AAT ICAS 1300 for information about the Inter-Dial Clock scale of time.

days in a uniform month are represented in terms of a two-digit number counting from the beginning of the uniform month. valid day numbers are from 01 to 30 for each uniform month. the 12th uniform month also possesses valid day numbers 31 to 35 in common years, and 31 to 36 in leap years. determination of a leap year in the Uniform Calendar system is specified in the New Calendar specification. yearend days including a leap day must be grouped after the principal 30 days of the 12th uniform month. any leap year or other adjustments for the Uniform Calendar must be applied to or from the last day of a calendar year.

## specification of uniform daygroups

a daygroup is a systematic method by which days are grouped within a month. uniform months in the Uniform Calendar may be divided into uniform daygroups that may be designated in terms of localized element sets per ICAS. uniform daygroups begin daygroup sequences from the first day of a uniform month. daygroups include:

- a uniform block (7-day) daygroup comprised of 4 uniform block daygroups plus 2 monthspace days grouped into a 30-day uniform month,
- a uniform stack (6-day) daygroup comprised of 5 uniform stack daygroups in a 30-day uniform month,
- a uniform track (5-day) daygroup comprised of 6 uniform track daygroups in a 30-day uniform month.

the 7-day Gregorian week daygroup may also be used with the uniform months of the Uniform Calendar; however must only be used in the Uniform Calendar in conformance with the weekdays in the Gregorian calendar.

aatideas.org document updated:

scale | value | ||
---|---|---|---|

UCN | 12019 S19 Yellow | ||

zone(UT) | t339 tt050 | ||

'ICAS in use' can accommodate calendar and clock formatting 'for all people, for all time'. | |||

AD common year day | 139 | ||

G | 2019 May 19 Sunday | ||

UT | 08:08:14 | ||

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