Tourists can enter the Observatory to gawp at the telescope. On the way up the hill to the building, I met a couple from Kuala Lumpur who were visiting all the telescopes in the district. They had their work cut out for them. There's a shi … lot.
This is the Anglo Australian Telescope. You reach the observation deck via a lot of fire stairs or a claustrophobia-inducing lift. I took the stairs. That tested my aerobic fitness. Epic fail.
The dome enclosing the telescope is 50 m tall. I'm not sure of its radius because that was the one figure I didn't write down. The telescope itself is 15 m long with a primary mirror with a working diameter of 3.893 m.
That mirror was cast in Toledo, Ohio, from a synthetic glass-like material called Cervit, which is extremely stable and doesn't respond to temperature changes. From the U.S., it was shipped to Newcastle-upon-Tyne where it was figured — polished into shape — over three and a half years. It eventually arrived at Siding Spring in December 1973. After being coated with aluminium* to give a reflective surface, the mirror was fitted and the telescope inaugurated just under a year later.
I was impressed.
* It is recoated annually with just 2.5 g of Al.
