IT IS OFFICIAL: Launceston's Shortest Day in 2011 will be June 22

Thank you for your enquiry. To my amazement, I find that the information on the Museum of Victoria's web page is incorrect.

The June solstice for 2011 occurs on June 21 at 17:17 Universal time, which is June 22 at 03:17 Eastern Standard Time in Australia.

The shortest day here - as in Melbourne - this year is therefore JUNE 22, not June 21. The longest night is the night of JUNE 21-22.

This does vary from year to year depending on the exact time of the solstice.

Part of the reason for the confusion is that some calendars are printed at different longitudes (latitude is not relevant). For example, in England, the longest day (not shortest, because England is in the northern hemisphere) is June 21, because the solstice this year falls on the local calendar date of June 21. This June 21 solstice date would also apply, for example, in South Africa, because of its longitude.

The reason for the variation of solstice time each year is because the year if 365.2422 days long - not a whole number of days. So the general trend is for the relevant event each year (e.g. the June solstice) to occur about 6 hours later for three years in a row, then to 'revert' to a time about 18 hours earlier because of the leap year inserting a day into the calendar. .

I hope this helps to clear things up !!

Yours sincerely,

Martin George

Queen Victoria Museum & Art Gallery