Further to circumpolar's fascinating description of Richmond's analemmic sundial, here's another I came across in Campbell Town, Tasmania. The analemma design does of course correct for the 'equation of time' and give a fairly accurate value for local time at the longitude of the sundial.
The descriptive plaque beside this amazing piece of machinery reads:
The Transit of Venus Sundial
This sundial was designed and built by Anthony Sprent in 2004 for Campbell Town [Tasmania] to commemorate the transit of the planet Venus across the face of the Sun, first observed at the Grange by scientists from the United States Naval Observatory in 1974. The latest transit took place on the 8th of June 2004, and will re-occur in 2012. The next pair of transits will take place in 2117 and 2125.
The sundial is made from old agricultural machinery located from proerties in the Campbell Town area. The design reflects the rural connections of the town and the historical significance of the astronomical observations made here in 1874.
To use the dial, sit on the seat then rotate the hand-wheel until the plough disk is facing the sun. Adjust the disk until the light of the sun through the small hole in front of the disc is shining on the line of dots engraved nearest the current month of the year. Now read the time displayed on the scale. The date is given by counting the number of dots since the beginning of the month to the dot where the sun is shining.
I wonder if there's enough material out there in IIS Land to justify a 'sundial' thread like the 'clouds' one? If so, perhaps these first two posts and subsequent ones should appear in 'Astronomy Science' rather than 'General Chat'?
Circumpolar's post is here:
http://www.iceinspace.com.au/forum/s...ad.php?t=19682
Further reading if you have a few spare hours:
http://en.wikipedia.org/wiki/Equation_of_time
http://www.mysundial.ca/tsp/time.html
