Saturday, 16 October 2010

Perfect seeing

The seeing is good tonight. Mind, it is not good sight or good vision. Good seeing is astronomy jargon that I have learned recently and therefore use with the novice's delight. Good seeing means that the air is clear and transparent. Preferably, you should be high up in the mountains. Cambridgeshire has bad seeing by definition. It has nothing to do with your telescope, or your eyesight, and you can have good seeing when it's cloudy. Seeing gets good after it has rained heavily, like today, so that all small particles of pollution have been washed away. My friend Jupiter is high over horizon which makes good seeing. One of its moons is in transit, which means that it moves in front of it. I cannot see it in my telescope, but I can see the other three moons. And I think I can see Uranus. Uranus is very hard to find unless you know where it is, and right now it is very close to Jupiter. There are no other bright stars near Jupiter, and from the star chart, Uranus should be where I can see it. It looks like a star in my scope, much too far away to see a disc. 

To view the Horsehead Nebula you need exceptional seeing. I don't think I will ever get that far.

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