Tuesday, 2 December 2008

Occultation of the Moon and Venus

One day I must actually learn to use the practical astronomy websites that generous people tell me about. But witnessing the occultation of the Moon and Venus was a great experience necessitating very little research!

Jules, on the Galaxy Zoo Forum, started a thread to let us know, which pointed me to SpaceWeather. Then, today, Paul from Skymania mentioned to me that the Moon was low in the south, and that Venus would disappear behind it, because they are lined up in the sky like overlapping galaxies. (Yes, that is a typical Alician take on it!) I couldn't find the Moon this afternoon, although I went up to the field at the top of our garden, the nearest I could get to a hill summit. There wasn't much cloud, but perhaps it was obscured by the ash trees. Those trees are splendid, and I wish they weren't in the south - if they weren't constantly lit up by the oil refineries at Milford Haven, the stars would come out behind them and they'd shine out like tiny pieces of magic fruit . . .

It was a pity it was the disappearance I missed, rather than the appearance. In layman's terms - and I bet there are professional terms for this - the Moon was lit up on the right this evening, and Venus was travelling from left to right. So this afternoon it would have appeared to just wink out in the sky. A split-second occurrence, but probably quite spooky. I saw it appear on the right of the moon at 5:10 p.m. this evening, when the sky was a very deep steely blue, with a watery pinkish-yellow sunset lingering a long way around the horizon.

It came out in a piercing burst of light, brighter than I had dreamed. It was as if a shard of splintered glass shone across the moon, giving the impression of being long and narrow - probably a trick of the light. I've heard that such astronomical events seem to be over in a heartbeat. Possibly because I was alone and extremely cold, this seemed to take forever. I kept waiting and waiting for Venus to detach from the Moon. I was lucky it wasn't over quickly, because at 5:15 p.m. I remembered that I own a telescope! A small blue skywatcher, which some good folks volunteering on a Telescope Amnesty night at Intech Planetarium told me has no mirror and is really for birdwatching - but it hugely improved things nonetheless. I ran inside to get it, trying to close my eyes to avoid losing their adaptation to the dark (the sky was quickly growing inky).

Too lazy to detach it from its tiny tripod, I dashed outside again, falling over a plant pot in the dark and hopping a few yards to avoid crashing to the wet muddy gravel. I struggled to hold it still, wishing it had a proper tripod my height. I went to try balancing it on the car roof, but from that angle I could only see the trees. Then I had a brainwave and propped it up on the gate:


It worked like a charm. The legs of the tripod held it in place, and I was able to adjust it to focus on the Moon and Venus! I was lucky the butterfly bush didn't obscure it. Venus still showed up as a white dot, like a star. But I did see some wonderful craters on the Moon. I'm used to seeing large detail, but these were tiny, and so very many! It was probably an ideal time to examine them, because the shadows from the Sun would be very long.

It's amazing how much things seem to move around in the telescope at random. Not the steady motion due to the Earth's rotation, but probably because I move without realising it, or jolt the telescope. I tried very hard to take a picture through my telescope and got a result so unimpressive I must share it with you here:

Without the flash it was pure black. I decline to bother uploading that one too.

You definitely need the right equipment for taking a good photograph - a tiny telescope and a mobile phone do not qualify! I did take a lovely one of the Sun last August with Jules's help - that story is here. Astronomy doesn't always favour the meticulous. I just dashed into this without doing any preparation; those who were probably more painstaking, and would have come away with a good photo, were in many places out of luck because of clouds in the way. But at least there'll be many next times. So let's all pay attention to the news snippets, even if we can't be bothered to read the websites. And if I can do this, folks, you definitely can!

4 comments:

Pat said...

I felt I was there with you looking at Venus and the Moon. Thanks for the experience Alice. :)

Waveney said...

Attempt three at a post...

Alice said...

Testing, testing one-two-three. Sorry you've had so much trouble, Waveney. This is my fifth attempt at a comment. I have played with the settings but am still looking for the source of the comments black hole . . .

Alice said...

Testing again . . .