UK and Polish team to observe the Sun’s atmosphere from Libya during 29 March eclipse

A team of three scientists and engineers from the Mullard Space Science Laboratory, UK, and the Astronomical Institute of the University of Wroclaw, Poland, are travelling to Libya to observe the total eclipse of the Sun on March 29th 2006. They will be using an instrument designed to understand why the Sun’s outer atmosphere is so hot.

The solar atmosphere or corona, which is normally only visible from the Earth at times of total solar eclipses, has a temperature of 1—2 million degrees Celsius. The corona also emits ultraviolet and X-ray radiation, which has been observed with spacecraft such as the ESA/NASA Solar and Heliospheric Observatory (SOHO). But despite more than 60 years of study, the heating mechanism of the corona remains unknown.

The instrument used by the Anglo-Polish team, the Solar Eclipse Coronal Imaging System (SECIS), consists of a double telescope on a driven mount with fast-frame electronic cameras that will form images of the corona during eclipse totality at the rate of 40 frames per second. This is far higher than can be accomplished with spacecraft instrumentation because of telemetry restrictions.

The aim is to search for subtle oscillations in the corona’s light intensity – tell-tale signs of heating by magnetic waves, thought by many to be the main heating mechanism on local scales. The oscillations are likely to have periods of a few seconds or less.

Previous observations with SECIS have been successfully made during the total solar eclipses in 1999 (Bulgaria) and 2001 (Zambia), with 12,000 and 16,000 images of the solar corona captured during the few-minute period of totality in each case. Analysis of the 1999 eclipse data suggests an intriguing possibility of a wave travelling along part of the corona.

The present expedition to Libya by the Anglo-Polish team with SECIS will obtain about 10,000 images in the slightly more than 4 minutes of totality. The solar corona should be a little dimmer than in 1999 and 2001, and have a different form as the Sun is now at sunspot minimum – the brightness and shape alter with the 11-year sunspot cycle.

The Anglo-Polish team are going out at the kind invitation of The Planetary Society (Mr Andy Lound, UK Coordinator) and The British Council (Libya), and they are forming a part of the Operation Eratosthenes 2 Expedition which involves a lecture tour in Libya. The observing site is at Jalu, an oasis about 350 km south of Benghazi. The team consists of Dr Pawel Rudawy, Dr Ken Phillips, and Dr Adam Buczylko.