The “pipehenge” was developed by New Zealander Eric Jackson and is used to teach astronomy during daylight hours. The steel construction can be used as a sundial, calendar, observatory, even a climbing frame. More importantly though, it can be used as a very effective teaching aid for the basic understanding of astronomy and the celestial sphere. In the past, astronomy has been taught from books. By using the pipehenge children actually become the “the compass” with their own bodies being the basis for an observatory.


1. Seat

This is the crossing point of the true NORTH/SOUTH and EAST/WEST lines; from which compass bearings are taken and from which observations looking North between the Summer and Winter arcs, and looking South through the circle, will be most accurate.

2. Circle

The pointers of the Southern Cross touch the inside of the circle as they move around the South Celestial Pole during the night. This Pole is in the centre of the circle.

3. Meridian

This line divides AM from PM East from West. When it’s shadow runs in a straight line from North to South it is Solar Noon local time.

4. Summer Arc

The path of the sun on the longest day (21 December) when it is directly overhead on the Tropic of Capricorn (Our Summer, Northern Winter)

5. Winter Arc

The path of the sun on the shortest day (21 June) when it is directly overhead on the Tropic of Cancer (our Winter, Northern Summer). Between these two arcs will be found the sun, moon, planets and many major star constellations.

6. Horizons

On March 21 and September 21, the sun rises exactly on East on the Eastern horizon and sets exactly on West on the Western horizon and travels half way between the two arcs. It is directly overhead on the Equator. Day and night are of equal length. Between March 21 and September 21 the nights are longer than the days. Between September 21 and March 21, the days are longer than the nights.

7. Compass Points

have been set out using Solar (true) North (See 3. Meridian)


These notes (in explanation of “pipehenge”) are courtesy of Mr Eric Jackson. The “Pipehenge” itself was donated to the Observatory by Mr Jackson and constructed by the Scouting movement of Australia, following the 1992 National Jamboree, held in Ballarat.