On Friday I showed another group of tourists around the William Herschel Telescope. Afterwards they were going on to GranTeCan, which is the huge telescope the Spanish are building at the Roque (see Thursday, July 26, 2007). I managed to tag along and finally see inside.
I’ve seen a lot of telescopes, and I knew it was huge, but I still wasn’t prepared for the sheer size of the thing.
This is the dome floor, which is 32 metres (93 ft). You could fit a full sized tennis court in there, and only the corners would be outside the rotating area. The huge red thing is the bottom of the telescope, with the main mirror (10.4 m) just out of the picture to the top.
The telescope isn’t finished (one reason why they allow so few visits) and they were working on the azimuth drive – the one that moves the telescope about a vertical axis. It’s silent, partly because it’s one, huge, linear motor.
I’d have loved to climb up inside the dome, but I was delighted to see this much.
