Maclear’s Beacon: much more than just a mound of rocks

Maclear’s Beacon: much more than just a mound of rocks

The highest point on Table Mountain is marked by a large cairn, built by Sir Thomas Maclear in 1865. But the cairn was not built to mark the height of Table Mountain, it was to assist in measuring the curvature of the earth.

This important astronomical calculation was undertaken by the Irish-born Maclear, a medical doctor who was also a keen astronomer. He was made a Fellow of the Royal Society of Astronomers and served as Her Majesty’s Astronomer and Director at the Royal Observatory at the Cape of Good Hope from 1833 to 1870.

One of Maclear’s most important tasks was to remeasure the Abbot Nicolas de Lacaille’s Cape Arc of Meridian. Due to the influence of the magnetic field of the mountains around the Cape on his instruments, Lacaille’s measurements in the mid-18th century had indicated that the Earth would be pear-shaped; the British Admiralty, however, wanted this enigma solved and Maclear set to work in the 1830s already.

The beacon was built on the highest point of Table Mountain, 1 086 metres above sea level, in 1865 as a triangulation station to assist in measuring the curvature of the Earth. The highest point on the mountain is 19 metres higher than the Upper Cable Station and on the furthest side of the cable station. The beacon is still used by cartographers.

Maclear was knighted in 1860 for his achievements in astronomy. He died in 1879 in Mowbray, Cape Town.

There is a 45-minute walk from the Upper Cable Station to Maclear’s Beacon, spanning the length of the mountain, approximately three kilometres. It is advisable to wear comfortable walking shoes to do the walk.

There are a number of walks on Table Mountain, with viewing decks which shows off different vistas of Cape Town. Every day there are two guided walking tours, at 10h00 and noon, which depart from the Upper Cable Station, giving you an opportunity to learn more about the amazing flora and fauna on Table Mountain, which is one of the New7Wonders of Nature, and part of the Cape Floral Region, a United Nations World Heritage site.

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