Wednesday, November 17, 2010

Telescope cherry

Of no interest to anyone else I am sure, but yesterday I looked up at space through a telescope for the first time.

My astronomy GCSE course has attempted this before, and again last night we trooped up to the famous 28" inch refracting telescope (the one used by Karen Gillan in Doctor Who Confidential earlier this year) only to find the view again obscured by clouds. The proper astronomer and our teacher filled time, explaining the history and mechanisms and testing our new-learnt knowledge. We waited and waited, and used a clever gadget called a 'window' to check if the sky might be clearing, but eventually decided to troop back into the warm.

Once we'd watched the telescope get put to bed and trooped down the steps and outside the Moon couldn't have been clearer - the tease. So the intrepid Nick who organises our group quickly found us an 8" inch reflector built by Meade: a bucket-shaped thing about the length of my forearm.

As the experts put this contraption together, Nimbos and grabbed a cup of tea and were then out in the cold again to queue up for a look.

The waxing gibbous moon looked shiny bright to the naked eye and, as thin cloud occasionally brushed over it, produced a glowing halo. This is due to icy crystals in the wintry cold atmosphere, which refract moonlight. The centre of the halo is bluish, the edge of it red - for the same reason as the different colours of the rainbow.

Looking through the telescope was something else entirely. At first I could see nothing but a white blur - as we'd been queuing the Earth's rotation had moved the telescope a bit. The helpful astronomer adjusted the setting and then - oh blimey - I saw.

A curved, gleaming surface of white, splotched with little craters, so bright it looked like plaster of Paris that had not quite set, the splotches made just a moment before I looked. The edges of these feature cast long, distinct shadows, picking out the details. The surface rippled slightly, as if I was looking through clear water - an effect of Earth's atmosphere refracting the light, something astronomers call 'seeing'. But another world, and in plain sight, tantalising, just out of reach.

Once we'd all wowed at this incredible view, the astronomers moved the telescope and trained it on Jupiter. With the naked eye, the huge planet looked like a bright star, hanging at about five o'clock below the Moon. Before we'd ventured out into the cold, we'd look at it using the free - and cool - Stellarium software which gave us an idea of what to expect: Jupiter in a line with its four largest moons.

But to actually see it! I took a moment to realise what I was looking at - the telescope flipping the image upside down, a reflection of the Stellarium cheat. A murky, stripey ball hanging in the darkness at the centre of the eyepiece. To the left (in reality, to the right) three bright stars - just the same size as Jupiter appeared to the naked eye. On the right, another star.

These moons, first seen by Galileo 400 years ago, transformed our understanding of our place in the universe. For more than 2,000 years the assumption had been that the Earth was at the centre of everything, that the celestial bodies looped slowly around us. Galileo tracked the positions of his four Galilean moons and showed why they moved and sometimes vanished. Now here was evidence of Moons circling something else: proof that we're not at the centre of things, the first sign that we live and toil on an insignificant sticky rock circling an insignificant star.

That is, except for something that's not insignificant: we look up.


Joseph Lidster said...

Joe likes this.

Keris said...

Absolutely gorgeous post. Thank you.