Re: Shipping Scopes


That sounds a lot like the famous "flying clock" experiment to test the
time dilation predictions of special relativity! Quite a story.

I think might be a challenge getting through TSA with cesium clocks and you
would not want to x-ray them.

Long baseline interferometry is still being done I think. Do you know how
they sync the receivers now?

There are ruggedized cesium clocks used by the military and aboard GPS
satellites. The ones used on the GPS satellites have to withstand launch


On Mon, Sep 28, 2020, 22:59 John Williams <> wrote:

Very interesting Steven. As far as shipping something with no danger of
damaging it, maybe from The Starship Enterprise by transporter beam! In
1969 we started doing long baseline interferometry which involved recording
radio telescope observations from three different radio observatories
around the world on 2 inch video tape. Once the observing process was
completed the tapes were all shipped to Ottawa for computer processing.
Recorded on the tapes was also a timing track consisting of pulses from a
caesium standard. So along with the tapes, the caesium clocks had to also
be shipped so they could all be synchronized. The only way we could make
sure they wouldn’t be damaged in transit was to buy two airline tickets.
There was one for the technician, and the other was for the clock. They had
to be in first class as the clock was too wide for coach seats. It did turn
some heads of the other passengers to see this huge case in the seat, with
lights blinking and radiation warning stickers plastered all over it. Those
were the good old days.

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