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Techies / Astronomers - Space Objects Question

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Techies, Astronomers, Space People -

When we send something into space, do we -

1) locate the object by its position above a fixed point on the earth, ie longitudinal and latitude and x miles above an earth position? or;

2) Every position in space has its own co-ordinates (x, y, z,). Seems impossible to do this to me? or;

3) NASA etc don't really know the location of their object co-ordinates but when in space miles are really irrelevant in the grand scheme of things? As long as you send a radar beam up and can measure the distance it is good enough?

I'm thinking like long distance travel to the moon, mars and further afield. How do you know the exact co-ordinates of your multi billion dollar project?

Ta.

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Techies, Astronomers, Space People -

When we send something into space, do we -

1) locate the object by its position above a fixed point on the earth, ie longitudinal and latitude and x miles above an earth position? or;

2) Every position in space has its own co-ordinates (x, y, z,). Seems impossible to do this to me? or;

3) NASA etc don't really know the location of their object co-ordinates but when in space miles are really irrelevant in the grand scheme of things? As long as you send a radar beam up and can measure the distance it is good enough?

I'm thinking like long distance travel to the moon, mars and further afield. How do you know the exact co-ordinates of your multi billion dollar project?

Ta.

There are a few ways. See here

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Here's a complicated pdf on attitude determination and spacecraft flight dynamics.

http://www.aerostudents.com/files/spaceEngineering2/attitudeDeterminationAndControl.pdf

Here's a simpler wiki explanation. Just read this.

http://en.wikipedia.org/wiki/Flight_dynamics_%28spacecraft%29

Thinking of going somewhere?

:blink:

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Techies, Astronomers, Space People -

When we send something into space, do we -

1) locate the object by its position above a fixed point on the earth, ie longitudinal and latitude and x miles above an earth position? or;

2) Every position in space has its own co-ordinates (x, y, z,). Seems impossible to do this to me? or;

3) NASA etc don't really know the location of their object co-ordinates but when in space miles are really irrelevant in the grand scheme of things? As long as you send a radar beam up and can measure the distance it is good enough?

I'm thinking like long distance travel to the moon, mars and further afield. How do you know the exact co-ordinates of your multi billion dollar project?

Ta.

you use the co-ord system that is most convenient for calculation; if it was me I would use a polar co-ordinate system based on whichever object the satllite is orbiting around, so typically the earth, but if it is a space probe, the sun

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Techies, Astronomers, Space People -

When we send something into space, do we -

1) locate the object by its position above a fixed point on the earth, ie longitudinal and latitude and x miles above an earth position? or;

2) Every position in space has its own co-ordinates (x, y, z,). Seems impossible to do this to me? or;

3) NASA etc don't really know the location of their object co-ordinates but when in space miles are really irrelevant in the grand scheme of things? As long as you send a radar beam up and can measure the distance it is good enough?

I'm thinking like long distance travel to the moon, mars and further afield. How do you know the exact co-ordinates of your multi billion dollar project?

Ta.

I would tell you but I worked on Beagle 2 - so it's probably best that I don't. :ph34r:

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I would tell you but I worked on Beagle 2 - so it's probably best that I don't. :ph34r:

Ha! I worked on Cassini-Huygens, albeit as a student. Haven't a clue about the celestial mechanics though - probably polar solar coordinates.

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The angle around, with north being zero. Then the angle up. Clearly the angle up depends on your latitude so you must subtract this when setting your telescope.

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When you send things into space you are lucky if you can find them again!

The Earth rotates, and your telescope will end up pointing the wrong way! ;)

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When you send things into space you are lucky if you can find them again!

The Earth rotates, and your telescope will end up pointing the wrong way! ;)

Yes, it's bloody annoying that that happens. Setting up a telescope to keep something in the field of view for long enough to look at it visually is OK but it takes quite a bit of fiddling around and adjusting and getting the motor right to take a decent long-exposure photograph (one reason I've never managed to)*. Look at something at high magnificiation and it flies through the field of view pretty quickly if you're not tracking.

* or cheat with a modern one full of electronics that can work it out itself, but where's the fun in that?

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* or cheat with a modern one full of electronics that can work it out itself, but where's the fun in that?

Use an Equatorial mount with a clockwork motor driving the Right Ascension! That could be fun, and no batteries required! :huh:

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Use an Equatorial mount with a clockwork motor driving the Right Ascension! That could be fun, and no batteries required! :huh:

I've not gone as far as a clockwork motor but do have an equatorial mount. Unfortunately it's not been used for ages. I left it at my parents (rural Cumbria, so nice dark skies) so my dad chucked it in the garage, piled a load of rubbish on it, covering it in muck, and broke a bit of the tripod. Some work to do before it's up and running again :(

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  • 331 Brexit, House prices and Summer 2020

    1. 1. Including the effects Brexit, where do you think average UK house prices will be relative to now in June 2020?


      • down 5% +
      • down 2.5%
      • Even
      • up 2.5%
      • up 5%



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