Thanks BenLurkin.
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Posted on 03/11/2020 6:44:59 AM PDT by BenLurkin
I just couldn’t conceive of great big globs of flotsam floating about between here and there, could you?
“As long as we can see it and it guides our sailors... We’ll be fine.” [jerod, post 4]
Polaris seems unmoving only to the unaided eye.
It actually “moves” in a small circle about the zenith of our planet’s north pole: a radius of about one degree, if my memory is accurate. Small as this sounds to an average citizen, failing to correct for it can induce significant errors in celestial navigation.
Timing and measuring must be very precise, to obtain usable information from celestial observations: a timing error of 15 seconds causes a position error of a nautical mile; an error in observing a star’s altitude of one minute of arc (one 60th of one degree of arc) can throw off the calculated position by up to one nautical mile.
The federal government used to publish tables that would permit users to correct for time of day and approximate location on the surface of the Earth. Not sure if it’s still being done; GPS and INS have changed the situation a great deal - for seafarers, aviators, and other users.
It could be that they don’t know as much as they think they do.
How could that be possible?
Thanks BenLurkin.
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Chang: I am constant as the Northern Star...
Leonard McCoy: [to Spock] I’d give real money if he’d [Chang] shut up.
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