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post #1 of 53 Old 02-03-2010 Thread Starter
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Celestial navigation (quiz)

The Aids to Navigation (quiz) thread, which I've been mostly luking on for a while, has inspired me to create a similar quiz for Celestial nav, mostly for selfish reasons.

I'll start, also sort of at the beginning:

What direction does the Earth revolve around the sun?
What direction does the sun revolve around the Earth?
What direction does the moon revolve around the Earth?

Please specify CW or CCW and specify what pole you're looking at.

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post #2 of 53 Old 02-03-2010
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OK I'll bite. Looking from the north pole down. IIFC.

The earth revolves around the sun CW.

The sun doesn't revolve around the earth.

The moon is CCW around the earth.
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Originally Posted by POLKA247 View Post
The sun doesn't revolve around the earth.
It's all relative. And it's useful to think of the motion of the sun around the Earth (really the Earth's rotation) for CN purposes.

Also, Earth around sun: CCW.

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Next one: in the intercept method, every time you use an assumed position with a celestial sight, you get a line of position through that AP. Why can't you just use a second assumed position with the same sight to get a second line of position?

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You could but it is still a single LOP and won't give you a fix.

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What instrutment do I use to determine what stars I will be using at twilight?

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Star finder.

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What term refers to the set of all possible geographical positions of the sun?

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You wouldn't by chance be referring to the Diurnal circle...Which is the path of a celestial body during its daily apparent revolution around the earth.

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Quote:
Originally Posted by POLKA247 View Post
OK I'll bite. Looking from the north pole down. IIFC.

The earth revolves around the sun CW.
I don't think this is right. When you are watching the constellations over a period of weeks and months they come up earlier every day, and the sun moves through the constellations in order, pisces, aries, taurus, etc, every month, and I think that could only happen if the earth is moving around the sun counter-clockwise looking down at it from the north pole.

Quote:
The sun doesn't revolve around the earth.

The moon is CCW around the earth.
That is true, you know because the moon comes up earlier every night, and because you can watch the sun move across its face through the month from right to left when you are facing south.

What are you pretending not to know ?

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