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If you're planning on doing a bit of stargazing with your own telescope tonight, or you're just an armchair astronomer, then how about watching The Sky Tonight show at the Royal Observatory's Planetarium first?
Presented by one of the observatory's own astronomers, this live show will give you a fantastic tour of the heavens so you'll know exactly what you can see if you aim your gaze skywards tonight. You might see anything from Jupiter and Mars to a visiting comet.
As well as pointing out all the obvious objects like the moon and which constellations are visible at this time of year, they'll also let you know whether there's something special happening like a meteor shower due.
Craig has never been to this actual planetarium show, but he has written a review of the Royal Observatory which includes a review of a different planetarium show. It's quite amazing inside -- you sit down in a reclining seat and the dome is dimmed down until it's pitch black (you can't even see your hand in front of your face), then they turn up the stars and the entire ceiling starts twinkling with them. It really is quite spectacular!
And there really is only one way to visit the observatory. Don't go by train. Don't go by bus. If you really want an enjoyable trip then catch one of the TRS boats from Big Ben to Greenwich.