Australian Eastern Standard Time Mullaley, New South Wales, Australia
By Mix on 06-Nov-04. Waypoint GA0101

Australian Eastern Standard Time.
(come an hour early for daylight savings or maybe you should come late)

The Who: You.

The Where: A Significant Sundial on the 150° East Meridian (almost, I think they used an old datum)

The What and When: Photograph the sundial exactly as it shows top, bottom or 1/4 of the hour with GPS in shot, record the time from your GPS to see the difference in time. (put your photos in the gallery)

The Why: Methods of measuring Time have varied over the ages, but the Time unit most commonly employed has been the apparent daily circuit of the Sun, from which Solar Time is derived. The Solar Day is based on one complete rotation of the Earth around its axis. Solar Days are not uniform in length, because the movement of the Earth around the Sun is irregular. Since the rhythm of mechanical timekeepers is constant, modern time calculation is based on the average Solar Day.

By dividing the 360° circumference of the Globe into 24, 24 time belts or Time Zones of 15° were created. As the Earth turns 360 degrees in 24 hours (or 15° in one hour), each Zone differs from Greenwich Time by a number of Whole Hours. That is why AEST which is based on the 150° E. Meridian Time, is 10 hours (150/15) ahead of Greenwich Mean Time (GMT).

All of NSW, Qld, Vic & Tas operate on AEST but the only time we hear 'The Pips' on time is when we are standing on the 150° E. Meridian. Because this Sundial is located on the 150° Meridian there is no correction to be made for the difference in Longitude between the position of the Sundial and the standard time. However, it must be remembered that because of the irregular movement of our planet, sundials seldom agree with watches!

BTW In the early days, the time used in each of the Australian Colonies was the Mean Solar Time of its Capital City and this often led to confusion until in 1892 at an Intercolonial Conference of Surveyors it was suggested that Australia should be divided into Three Time Zones. In 1895 AEST was adopted as the Standard Time for the Eastern States. This Standard Time is determined and signalled by the Sydney Observatory.