Where are we?

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Kate Humble: Mike Leahy’s conjuring up a quadrant. It’s a device for measuring our angle to the stars.

Mike Leahy: So for the North Star simply look through these two washers until you’ve sighted it.

Kate: The recipe for our castaway radio includes the handle of an old rake, a tangle of wire and a saucepan. As the sun sets, Mike and Jonathan go star gazing.

Mike: The North Star when we aimed at it, the plumb line was here where we’ve marked it with a pencil so we’re fairly confident our latitude’s 43 degrees north.

Kate: What we need to crack on with now is our longitude.

Mike: Yeah, that’s not such a simple problem.

Kate: Mike’s task, to pinpoint local noon with an improvised castaway sun dial. When the shadow of the stick hits the line it’s noon.

Jonathan Hare: This barbed wire which ...

Kate: The amazing saucepan radio with its improvised aerial is about to be put to the test. There’s not a thing happening, just not a thing.

Jonathan: Okay, so we can – now did you hear a crackle or anything when I moved this around?

Kate: Yeah, yeah, a little bit of like static noise.

Jonathan: Okay, so we’ve got to play around with the tuning and the contact on here.

Kate: We need to improvise a clock and Mike’s planning a pendulum. The four metre pendulum will give you a back and forth swing of four seconds.

[Radio broadcast]

Jonathan: 12.24. 12.24, we’ve got a time. Hey Mike! We’ve got a time.

Kate: It’s now or never for longitude. The number of swings of the pendulum will allow us to calculate the difference in time between our noon and GMT.

[Whistle] It’s noon!

Mike: Right, so 3,364 seconds, how many minutes is that? 3,364 divided by ...

Kate: The moment of truth - where on earth are we?