Tuesday 29 October 2013

Cranfield Astronomical Society

I have started attending an astronomy class at Cranfield University, which is just a short evening class for 8 weeks run by Cranfield Astronomical Society. They give some short talks each week and then if the weather is good, are eager to get outside and get some kit out to look upwards.

Last night was the first night we went outside (only my second week to be fair - last week was thunder storms!). It was cold and really clear. They have a small observatory with the main bit of kit being a Celestron C11. I didn't get a chance to look through the C11 as there were quite a few others lining up for a go and to be honest I was more interested at that point seeing what was going on outside.

They also set up a 80mm refractor, a 100mm refector and a 10" Dobsonian.

I cannot remember the guy's name, but he was setting up his personal kit, which consisted of a hefty go-to motorised mount, I can't remember exactly, but it was some Newtonian reflector ~11" telescope (big bugger), with a really cool auto-tracking system, which uses a smaller telescope mounted on the side with a webcam, which is connected to a computer and watches the stars and drives the mount accordingly. Onto this he could then mount a modified Canon D500 DSLR to do some deep sky object photography.

The mount can auto-track itself, but when trying to photograph long exposures of deep sky objects, even the slightest mis-track would result in a blurry image.

Last night he was photographing M31, the Andromeda galaxy, a favourite galaxy of many as it is one of the closest galaxies to us. It is the closest spiral galaxy, but the closest overall galaxy. It is 'only' approximately 2.5 million lightyears (not 200 million as unfortunately 2 astronomers at the class said it was, which I knew was wrong, but I wasn't about to start correcting people) from us. Small-ish in universe scales, but to us humans, so very, very far (23,668,200,000,000,000 km). Very far but also it means that as we look at it (possible with the unaided eye on a good night), we are seeing it as it appeared about 2.5 million years ago. So even as a close neighbour, we can only see what it was up to 2.5 million years ago. That could start a whole other discussion about why this buggers up ideas of making contact with 'things' in other galaxies (with current technology).

But, anyway, this guy was taking 2 minutes exposures (ISO 800) and every photo was just mind blowing. You could zoom in and see the dust trails already, just in the raw, unprocessed image. It really brings it home that these things are real and there as this guy just pointed a camera at it and took its picture. I think so many people think astronomy is just pretty colourful pictures just like abstract paintings, failing to see that they are images of real things, just like if I took a photo of my cat or the clouds in the sky.

It is hard to perceive depth and 3D in these images as they are so far away, but that's what's good about M31, it is kind of side on, so you get a sense of it being a 'disc' in space, with the front dust trails getting in the way of the rest of it.

He is going to stack up several of these images (to improve the the signal to noise ratio), so I can't wait to see the final result.

To make things more interesting, Jupiter rose whilst we were out, so the two refractors were pointed at that and through the 100mm you could clearly make out two main bands around Jupiter...and of course the Galilean moons. I can just about make out the moons through my 15x70 binoculars.

I look forward to seeing more, hopefully through the C11 next time.

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