6 - European Northern Observatory and Calar Alto

Summary

European Northern Observatory, Canary Islands

Night-time Telescopes on Tenerife

The Astronomer Royal for Scotland, Charles Piazzi Smyth, set up two small astronomical stations at high altitude on Tenerife in the Spanish Canary Islands in 1856. Although they were not there for very long, these observatories were the first to show the great advantage of observing at high altitude.(1) No one took much notice, however, and it was not until over fifty years later that Jean Mascart of the Paris Observatory suggested that an international astronomical observatory should be established on Mount Guajara on Tenerife. Discussions then started between the Spanish, French and German governments, but they were abandoned at the start of the First World War.

There was no progress with the idea of setting up an observatory at high altitude in the Canaries for a number of years. But astronomers observed a total solar eclipse from the Canaries in 1959. In the same year Spain founded the Observatorio del Teide at Izana, on Tenerife, at an altitude of 2,380 m (7,250 ft). A 30 cm (12 inch) French photopolarimeter was installed there in 1964 to study the zodiacal light, followed by a Spanish 25 cm heliographic telescope in 1969. The largest telescope at El Teide (now part of the European Northern Observatory) is the UK's 1.5 m Infrared Flux Collector (IRFC) that was built in 1971 as the prototype for the 3.8 m United Kingdom Infrared Telescope that was completed on Mauna Kea eight years later.

Site surveys carried out by JOSO (Joint Organization for Solar Observations) in the 1970s indicated that although El Teide on Tenerife was the better Canary Islands site for solar observations (see Solar telescopes later), the Roque de los Muchachos on La Palma was better for night-time observations. So although night-time telescopes continued to be built at El Teide (see Table 6.1), the largest such telescopes were built on La Palma (see Table 6.2).