A small rock in the Atlantic: 21/08/2011

The William Herschel Telescope

The William Herschel Telescope at sunset.

The William Herschel Telescope was for many years the biggest and best optical telescope in Europe (until GranTeCan opened in 2009). The main mirror is 4.2 m across (165", or 13' 9") which astronomers call "a good light bucket". It's rather old as world-class telescopes go, since it opened in 1987, but it still produced excellent science. In fact data from the WHT has been used for about 1,500 scientific papers. It helps that it's been fitted with adaptive optics.

This is when you use some starlight to measure the air turbulence, and then deform a special, flexible mirror to compensate for that turbulence. It's rather like using glasses to correct for the shape of your eyeball, but these glasses change shape 100 times a second.

This only works if you have a bright star handy, in order to measure the turbulence in the first place. Some parts of the sky have far more stars than others, so the WHT has a laser, which can be used to create an artificial star. To the best of my knowledge, it's the only one working in Europe (although GranTeCan will have one too.)

The telescope's named after Frederick William Herschel, who was born in Germany but emigrated to England. He started life as a musician, but music lead to mathematics and then to astronomy. He's best known for discovering the planet Uranus, but he also measured the height of the mountains on the moon, discovered double stars, catalogued loads of nebulas, found two of Saturn's moons and two of Uranus's moons, and was the first to realise that the solar system is moving around the galaxy. Oh, and he discovered infra-red radiation.

Pretty impressive for someone who didn't really get started on astronomy until his mid-forties. (Obviously there's hope for me yet.)

If you want to visit the WHT, you have to sign up in advance for a visit with the IAC. Details at: http://www.iac.es/eno.php?op1=2&op2=420&lang=en

Inside the William Herschel Telescope, beside the secondary mirror.

Labels: astronomy, La Palma, observatory, Roque de los Muchachos, telescopes, William Herschel Telescope

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Terrific time-lapse video of La Palma

Teaser: "The Island" - La Palma Time Lapse Video from Christoph Malin on Vimeo.

Enjoy Christoph Malin's wonderful time-lapse video of La Palma. He very nearly does the place justice.

Labels: astronomy, Caldera de Taburiente

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Los Tilos: Ancient Forest

Laurel forest at Los Tilos

One of my favourite bits of tourist feedback about La Palma island was the disgruntled Brit who described Los Tilos as: "Just a load of trees."

Well yes. And Beethoven's Ninth is just a load of notes, and the Mona Lisa is just a load of paint.

Los Tilos, in San Andres and Los Sauces, is home to one of the best surviving laurel forests in the world. (The other one is Garajonay, in La Gomera).

The river bed at Los Tilos

What's so great about a laurel forest?

It's what the dinosaurs walked through. To be fair, if you can't tell an oak from a birch, then it's just a pretty, shady walk.

Stag's head lichen

On the other hand, if you're a professional plant scientist, like my father, you feel like a small kid in a sweet shop, because the place is full of plants that grow nowhere else. My father got too excited to finish his sentences, and it took him twenty minutes to walk a hundred yards.

An aeonium

The plants are rare enough that whole place is a World Biosphere Reserve. The original 511 hectares were declared a reserve in 1983, but this wasn't big enough to do the job properly, so in 1998 it was extended. They didn't muck about. The new reserve is 13,240 hectares. That's 5% of the island!

The restaurant at Los Tilos

There's also a friendly bar, which is great if you work up a thirst. There are very tame little birds, which I believe are Canary Chaffinches (Fringilla coelebs tintillon). If you know better, please let me know!