Recent Eclipse Experiences
1973: Concorde 001 over Africa
For the eclipse of 30 June 1973, the newly developed Concorde 001 made an historical flight, funded by CNES and CNRS, with participation on international teams from France, UK and the US.
Thanks to Concorde's supersonic speed of Mach 2, a total of 74 minutes of totality was obtained by different teams with special equipment on board. The trajectory allowed an inertial orientation (fixed orientation compared to the stars) in the totality zone over Africa, at 16-17 km altitude. The itinerary was followed by test pilot A. Turcat with an accuracy of one second.
The photographic work and infrared experiments were conducted with technical success. However the analysis of the images showed optical aberrations due to the external turbulent atmosphere compressed by the aeroplane shock, giving a lower image quality than that obtained from the ground eclipse sites.
1991: Hawaii - Baja California
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Figure 1. Eclipse 1991 |
On the day itself, it rained over Hawaii, and only astronomers from the volcano summit were above the sea of clouds. The Canada France Hawaii 3.6-m telescope (CFHT) and UK infrared 3-metre telescopes were pointed toward the Sun (during eclipse totality) for the first time. Some remaining dust from the recent Pinatubo eruption perturbed the sky. However several experiments obtained during four minutes of totality yielded new observations in different wavelengths, with results on dynamics and fine structures in the corona, the ejection of plasma clouds and interplanetary dust.
1994: North Chile Desert
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Figure 2. SSD team in Chile |
Several expeditions were mounted to study this eclipse in Peru and Bolivia, including one from ESA's Space Science Department. The SSD expedition, led by B.H. Foing, was installed in the military base of Putre (at 3 500 metres) in the north Chilean desert, together with international eclipse experiment teams from Asia, Europe and America. The SSD team installed a transportable 25-cm telescope equipped with spectrograph and fast CCD camera, as well as other experiments with smaller telescopes.
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Figure 3. SSD team in Chile |
Figure 4. SSD team in Chile |
Several lightweight telescopes were also carried by more intrepid colleagues from a mountain climbing expedition to achieve the highest altitude ground-based observations of eclipses with a light telescope (5 300 metres) and with a camera (6 300 metre summit of Parinacota volcano).
1995: India - Vietnam
The eclipse of 25 October 1995 was the last solar eclipse before the launch of SOHO observatory on 2 December 1995. Data was obtained in co-ordination with the Yohkoh X-ray solar satellite.
At the same time a large international conference in astrophysics and fundamental physics took place in Ho Chi Minh City, allowing its participants to conduct some experiments, or their first visual eclipse observations, in a camp in the Tay Ninh province near the Cambodian border.
The 1994 and 1995 eclipse coronal images show structures with large streamers in the equator and plumes near the poles, a configuration characteristic of a solar minimum phase of activity.
1998: Venezuela - Antilles
For the 1998 eclipse a series of expeditions were well co-ordinated with SOHO observations, which ran predefined observing sequences with different instruments (see also the related link to the SOHO eclipse 1998 pages: http://sohowww.estec.esa.nl/soc/ECLIPSE/).
The eclipse campaign in Guadeloupe was accompanied by an international scientific conference on Solar corona in Pointe-a-Pitre, with emphasis on results from eclipse and space observatories, and by strong scientific, media and public activities.
Among other teams, the ESA SSD eclipse team performed 4 experiments of imaging using two 25-cm telescopes and large CCDs.
Daily SOHO images on the Internet were very useful in the days preceding the eclipse, to monitor and predict what was to be present at the limb the day of the eclipse, and to plan observations.