80
Without further ado, I extracted the usable data from the abundant archives
of the Izaña Meteorological Observatory, which date from the beginning of
the twentieth century. I concentrated on the previous twenty years (from
1947 to 1966) in order to overlap them with the measurements we had been
taking. The results were quite clear: on only 2.2 per cent of clear days was
there any appreciable presence of dust in the atmosphere above 2400 metres.
We reported in a publication of 1970: ‘From November to February, both
inclusive, the number of days without cloud but with dust is less than 1%,
and even in the worst summer months the value does not exceed 10.5%.’
In spite of the weight of these data and the fact that we have been accumulating more and more observations for over fifty years, all concordant with our
1970 paper, there are still those who argue against setting up more telescopes
in the Canaries, their case still being based the myth of blankets of Saharan
dust descending on the IAC Observatories. Again and again, it has been necessary to counter energetically these lies and biases with data. It must not be
forgotten that there are powerful interests at play where large scientific structures are concerned. Our latest examples of myth-busting efforts include the
European Extremely Large Telescope (E-ELT) and the Cherenkov Telescope
Array (CTA): we lost the battle for the E-ELT and were victorious with the
CTA (see Chap. 22).
The first to decide not to bring their telescopes to the Canaries were colleagues from the former Federal Republic of Germany. An expedition from
Heidelberg Observatory came to Tenerife in 1960 to examine the astronomical suitability of its mountain sites. Their brief stay coincided with a Saharan
dust invasion, and they immediately concluded that the Canaries were unsuitable because of dust in suspension. They did not trouble themselves to see
what might happen during the rest of the year. The Heidelberg Observatory
team settled for the Sierra de Filabres in Almería, where the net astronomical
observing conditions are poorer and ironically, as in the rest of southern
Europe, there are occasional dust invasions.
It is timely to note here that the first international agreement permitting
the setting up of a telescope in the Canaries was signed in 1965 with the
University of Bordeaux. Thanks to this agreement, Teide Observatory was
blessed with a photopolarimetric telescope (now known as the Bordeaux
Telescope, on exhibition today in the vestibule of the IAC Library in La
Laguna). The first Spanish astrophysical research team was nurtured with this
telescope. This agreement was to serve as a template for all subsequent accords:
a foreign scientific institution sets up its telescope at one of the IAC
Observatories, Spain provides extraordinary observing conditions and basic
infrastructure, the allocation of observing time, etc., and the agreement
is signed.
F. Sánchez
Without further ado, I extracted the usable data from the abundant archives
of the Izaña Meteorological Observatory, which date from the beginning of
the twentieth century. I concentrated on the previous twenty years (from
1947 to 1966) in order to overlap them with the measurements we had been
taking. The results were quite clear: on only 2.2 per cent of clear days was
there any appreciable presence of dust in the atmosphere above 2400 metres.
We reported in a publication of 1970: ‘From November to February, both
inclusive, the number of days without cloud but with dust is less than 1%,
and even in the worst summer months the value does not exceed 10.5%.’
In spite of the weight of these data and the fact that we have been accumulating more and more observations for over fifty years, all concordant with our
1970 paper, there are still those who argue against setting up more telescopes
in the Canaries, their case still being based the myth of blankets of Saharan
dust descending on the IAC Observatories. Again and again, it has been necessary to counter energetically these lies and biases with data. It must not be
forgotten that there are powerful interests at play where large scientific structures are concerned. Our latest examples of myth-busting efforts include the
European Extremely Large Telescope (E-ELT) and the Cherenkov Telescope
Array (CTA): we lost the battle for the E-ELT and were victorious with the
CTA (see Chap. 22).
The first to decide not to bring their telescopes to the Canaries were colleagues from the former Federal Republic of Germany. An expedition from
Heidelberg Observatory came to Tenerife in 1960 to examine the astronomical suitability of its mountain sites. Their brief stay coincided with a Saharan
dust invasion, and they immediately concluded that the Canaries were unsuitable because of dust in suspension. They did not trouble themselves to see
what might happen during the rest of the year. The Heidelberg Observatory
team settled for the Sierra de Filabres in Almería, where the net astronomical
observing conditions are poorer and ironically, as in the rest of southern
Europe, there are occasional dust invasions.
It is timely to note here that the first international agreement permitting
the setting up of a telescope in the Canaries was signed in 1965 with the
University of Bordeaux. Thanks to this agreement, Teide Observatory was
blessed with a photopolarimetric telescope (now known as the Bordeaux
Telescope, on exhibition today in the vestibule of the IAC Library in La
Laguna). The first Spanish astrophysical research team was nurtured with this
telescope. This agreement was to serve as a template for all subsequent accords:
a foreign scientific institution sets up its telescope at one of the IAC
Observatories, Spain provides extraordinary observing conditions and basic
infrastructure, the allocation of observing time, etc., and the agreement
is signed.
F. Sánchez