CalculationTime

Sun, Moon & Sky

Southern Cross Time and Date Calculator

Know the date and read the Hand of the Cross for the hour. Know the hour and read it for the date.

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Hand of the Cross: 270.3° · 45.1 minute-marks

Three ways to drive it

What should update by itself?

Set the date and standard time; the Hand of the Cross follows.

Standard time UTC+10 all year. Daylight saving is not used.

Hand of the Cross angle270.3°Above the horizon at 24.3° altitude. Standard time only.

One minute-mark of the dial is about 24 minutes of clock time on one night, or 6 days of the year at a fixed hour. Half a minute-mark is about ±10 minutes or ±3 days.

Print Room

Print or copy the Crux sky-clock proof

Use the print room and Copy full report controls to keep the Hand of the Cross angle, solve direction, AEST calibration, assumptions, source boundary and page URL together.

In depth

How the Hand tells hour and season

“At a known season, Crux can help tell the hour; at a known hour, its orientation can help indicate the season.”Modern summary of José de Acosta, Historia natural y moral de las Indias (1590)

At the same hour each night, the Hand of the Cross stands a little further round: about one minute-mark every six days, one hour-mark each month, and all the way round in a year. So the date gives the hour, and the hour gives the date.

Fast sweep: the clock

Within one night, the Hand of the Cross moves 15.04° per hour - close enough to an ordinary 24-hour dial that a given angle tells you the time, precisely, once you know the date.

Slow creep: the calendar

At the same standard-time hour, the Hand moves about one minute-mark every six days and one hour-mark each month.

One motion, two tools

Nothing about the sky changed between the two readings - only which rate you chose to pay attention to. That is the whole trick behind reading stars as instruments.

What is the Hand of the Cross?

The Hand of the Cross starts at the South Celestial Pole and splits the angle between Acrux and Gacrux. XII means the Cross is upright, with its head above the pole.

How closely can I read the time or date?

Reading the Hand by eye to half a minute-mark gives the time to about 10 minutes on a known night, or the date to about three days at a known hour.

Why can the same dial tell time and date?

During one night the Hand sweeps around the pole like a clock hand. At the same standard-time hour on later nights it stands about one minute-mark further round every six days, one hour-mark each month, and one full turn each year.

Where is the zero reference?

The Hand reads XII at midnight on 31 March 2026, standard time, on the 148.6393°E meridian, just east of St George, Queensland. Longitude sets the reading; latitude is used only to check whether the Cross is above the horizon.

Does daylight saving change the answer?

The calculator uses standard time all year. If your clock is showing daylight-saving time, change it to the standard-time reading before comparing it with the Hand.

Related reading: Crux Perpetual signature clockface.

Keep going

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Sources and checks

Source, method and limitation basis

This calibration - the 148.6393°E midnight-zero meridian just east of St George, Queensland, referenced against standard time (UTC+10) at midnight on 31 March 2026, using the IAU 1982 GMST formula - is shared across this page, the signature clockface, the Twin Clocks of Earth dials, Crux Perpetual and the Developer API's Crux Sidereal Ephemeris Engine. The Crux Perpetual: a hand drawn from the South Celestial Pole, bisecting the angle to Acrux and Gacrux. Last checked 2026-09-23.

Sources and further readingCalculationTime Developer API: Crux Sidereal Ephemeris EngineCrux Perpetual signature clockface