Another rare confluence of the International Space Station flying over London on a clear night should take place on Tuesday evening.
According to the weather forecasts, the night sky will be very clear at 9pm
Assuming that all is well, what you want to do is find a nice place with a decent view of the sky — a park, or anywhere above the local street lighting level will do.
It should become visible around about 9:02pm on Tuesday 15th April, depending on how much of the horizon you can see, and pass right overhead just after 9:05pm.
To see it, face directly to the West a couple of minutes before it is due to arrive to get used to the dark sky — then watch out for a single bright star flying in a straight line directly towards you and overheard. That’s the space station. It takes a moment to spot it, but once you do, it becomes very noticeable.
You should be able to watch it for a minute or two as it flies over.
Technically, the space station passes just inside the M25 barrier to qualify as “over London” for my purposes — but because of its height, it will appear to be right overhead from the ground, regardless of where you are in London.
Don’t forget to give the astronauts a wave as they fly over!
The ISS will be visible from most of England — and the flypast last a couple of minutes over England, so the times are as above, give or take 10-20 seconds. Obviously, if you are north of London, you will need to look very slightly to the southern half of the sky above.