To aid the British effort the House of Commons voted £10,500 to defray the cost of instruments and observations, and a further grant of £5000 was made to cover photographic apparatus and photographers.

Mr Richard Proctor, the famous populariser of astronomy, argued with Sir George Airy, the Astronomer Royal, about suitable sites, suggesting that a station on the Antarctic continent (Possession Island, near Victoria Land) should be used for both the 1874 and 1882 transits, and also that a site in northern India would be useful. The multitude of southern sites was supposedly to mitigate the strong chance of inclement weather. The Royal Navy was given the task of ferrying the astronomers to and fro. The Hydographer (Admiral Richards) was distinctly unimpressed. Even though the astronomers might be enthusiastic he still thought them to be “deficient on many subjects which it is necessary to take into account …. We are told to sail to the Antarctic Continent and to visit a variety of small rocky islets interspersed over the Southern Ocean …. many of which are actual myths, while on those which do exist it is certain that there is no anchorage for a ship, and that even landing would be generally impossible.”

The end-results of all this planning, travelling, expense and observing effort were dismal. High-quality optics, and improved observational techniques had reduced the black-drop problem somewhat, but even the new photographic approach resulted in distorted images. It turned out that the errors had only been reduced by a factor of two over the 120 years since the previous pair of transits. Many were the accounts of continuous cloud, poor timekeeping and excessive image turbulence. On Kerguelen (48.5° S; 70° E, an isolated island in the Southern Ocean, south of a line between South Africa and Australia) the British expedition was instructed by Airy to stay an extra 12 weeks in order to make over a hundred observations of the Moon. These provided an accurate value of the longitude of the site. However, the astronomers nearly ran out of food and were forced to go onto half rations.

Interest in the December 1882 transits started to seriously wane. Even so the French Academy of Sciences organised expeditions to Haiti, Mexico, Martinique, Florida, Patagonia, Chile, Rio-Negro, Cape Horn, Argentina and Montevideo. David Gill, however, recognised the fact that transit observations would never yield good results. He wrote “the transit of Venus in 1882 was therefore awaited at the Cape without special interest.” One famous French astronomer, Urbain J. J. Leverrier (1811 – 1877) would have nothing to do with either the 1874 or 1882 transits. He concentrated on three gravitational approaches. The orbits of Venus and Mars are perturbed by the mass of the Earth; the orbit of Earth is perturbed by the mass of the Moon and the speed of the Moon around its orbit depends on the gravitational influence of the Sun. All three effects depend on the astronomical unit and their careful measurement yields a more accurate value of the AU than the transit approach.

The US Naval Observatory was criticised in the press for sending extravagant expeditions to distant parts. Even worse, funding for the analysis of the observations was mostly used for other purposes and interest in analysing the observations faded away.

In the century that followed, observers turned to Mars, the Moon, nearby asteroids and radar for accurate measurements of the astronomical unit. They sensibly tried to replace ‘special occasion’ transit observations, which can be rendered useless by all kinds of weather, travel and observing accidents, by more reliable large-observatory techniques that permitted many repetitions of significant observations to be made in relative comfort.

Today the astronomical unit is quoted to a few tens of metres. In 2004 the Venus transit is treated by most as an oddity of mere historic interest. Professional astronomers are indifferent. Astronomy has changed almost beyond recognition since 1882. The next transit cycle starts in 2117. Our children’s children’s children might be tucked up in bed on Mars by then.