Calendar systems & names

The whole calendar can count in one of sixteen traditions. The days themselves never move; the chosen system gives them its own months, years and week.

Where it is. Settings › time & directions › calendar system, with "names as" and "day names show as" below it. The assistant can set these too.

#Choose a system

One chip per system, in this order: "gregorian" · "chinese" · "korean" · "vietnamese" · "hebrew" · "hijri · umm al-qura" · "hijri · tabular" · "persian" · "vikram samvat" · "indian national" · "ethiopian" · "coptic" · "julian" · "thai" · "japanese" · "bahá'í".

• Default: "gregorian", which is free. The chosen chip wears "✓".
• Every other system is (Gold). Without Gold its chip wears "✦", and a tap opens the Gold offer instead. A system you already chose is never switched off if Gold lapses.
• How exact it is. Under the chips, a line tells you how far to trust the chosen system. "exact" means pure arithmetic, so every date is certain. "astronomical" means computed from the sun and moon, so a month that begins close to midnight can land a day away from a printed table. "approximate" means that in real life the date is decided by observation, so it can differ by a day. Hijri umm al-qura and bahá'í have lines of their own naming their limits.

#What changes when you choose a tradition

• Dates everywhere. Every title and date line takes its words from the chosen system, for example "10 izzat 183 be". The Gregorian date is shown small beside it on the big date, the day brief — the list of a day's commitments along the bottom of the screen — the commitment editor, and a commitment's page.
• An almanac's list. Each row in an almanac's list — an almanac is one of your calendars, a named, coloured layer of commitments — is dated in the chosen system, in short form, such as "10 izzat". The widgets use the same short form.
• The year ring. The orrery — your year drawn as an orbit round the sun — lays the system's months along the earth's real orbit.
• The week. The tradition decides which day begins the week. The seven day chips give way to one line naming that day, and your own choice comes back when you return to gregorian.
• Repeats. A monthly or yearly repeat made while a system is chosen counts that system's months and years. It keeps its system even if you choose another later.

#"names as"

Shown only while a system other than gregorian is chosen. It sets how the tradition's names — its months, its day names and its year words — are written. Three choices:

• One setting serves every tradition, and it is kept when you switch between them.
• "translation" stays greyed for a tradition whose months mostly have no agreed meaning. A name with no meaning anyone agrees on keeps its romanization rather than an invented translation.
• "original script" is left out when the phone has no font for that script.
• Digits stay 0–9 in every form.
• Names in Hebrew, Arabic and Persian read right to left in original script. The screens themselves keep their left-to-right layout on every phone, whatever its language.
• The choice applies to the whole sky at once.

#"day names show as"

How weekday names are written in the week and month headers. Four chips: "U", "Su", "SUN" and "☉ ☽ ♄" — one letter, two letters, three letters, or the days' classical planets (sun, moon, mars, mercury, jupiter, venus, saturn). One letter uses U M T W R F S. Default: one letter.

#Languages and scripts

The app's own words are lowercase English. Weekday names and gregorian month names come from your phone's language. Scripts that join or stack their letters drop the app's wide letter spacing.

See also. Time & directions · The orrery · Times & repeats · Zenith Gold in the calendar (Gold)