The big telescopes at the observatory at the Roque de Los Muchachos mostly use mirrors rather than lenses. Domestic mirrors have the aluminium behind glass to protect it, but astronomical mirrors have the aluminium on top. This gives the best image, but it also means that the aluminium slowly spoils, and has to be replaced every three years or so. This is not a simple operation. The aluminium layer is…
GranTeCan is the biggest optical telescope in the world, and it’s hard to convey the sheer size of it in a photograph. The telescope itself weighs 485 tonnes. You could fit an tennis court inside the dome, and the top of the dome is 41 m above the ground. But you can’t see any of that in a photograph. Luckily for me, the engineers did some maintenance on the massive…
Putting the Galileo’s mirror onto the carrying case, which is on the lorry. I didn’t have any guiding work yesterday, but I drove up the mountain anyway. I wanted to get photos of people moving the main mirror from the Galileo to the Herschel telescope for realuminizing. They only do this once every three years, so I was keen not to miss it. That mirror weighs about 6 tonnes, and…
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…
Two of the fourteen telescopes at the Roque de los Muchachos observatory are solar telescopes — highly specialised to observe our own sun. This is the Swedish Solar Telescope, which was one of the first telescopes built on the Roque. It’s currently the best solar telescope in the world since they added the new adaptive optics in 2005. (Adaptive optics compensate for air turbulence.) It can resolve details of the…
The Canary Islands are known as the land of eternal spring, but that’s not quite true at 2,396 metres (7,861 ft). Down at sea-level, it’s been raining. Up on the mountain, it’s been snowing. Yesterday the road was only suitable for 4-wheel-drive vehicles, but I gather the road is open again. If you’re on La Palma, this is your chance to make a snowman. But drive carefully, and once you…