Author Topic: Spacecraft navigation and celestial equator  (Read 1275 times)

Offline Apollo-phill

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Spacecraft navigation and celestial equator
« on: 02/16/2012 02:44 pm »
I was reading a book about star names last night ( I know very quirky English Victorian  traits ! ) and it was saying that 4000 years ago the celestial equator was 12 degrees below where it is currently . For instance,nowadays the celestial equator passes close to the star sometimes called Mintaka in the 'belt' of constellation Orion but was 12 degrees lower down 4000 years ago.

This got me thinking and couldn't find answer anywhere.

Do planetary probe planners and trajectory engineers have to take into account - for long duration missions like,say,Voyager or New Horizons - the minute change in the 'positional values' of the celestial equator over the course,of say, 5 or 10 years  ?

I would not have thought it was too 'important' for inner planetary probes like MSL, Lunar Prospector and so on ?

Couldn't find any references in guidance books I have.

If they do have to use a value anyone any idea what value they use?


A-P

Offline Apollo-phill

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Re: Spacecraft navigation and celestial equator
« Reply #1 on: 02/16/2012 08:41 pm »
OK Forget question.

I have discovered the answer ;D ;D

A-P

Offline grakenverb

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Re: Spacecraft navigation and celestial equator
« Reply #2 on: 02/17/2012 03:08 am »
Well, you have to share it with the rest of us now :)


Offline Proponent

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Re: Spacecraft navigation and celestial equator
« Reply #3 on: 02/17/2012 03:48 am »
Precession of the earth's axis of rotation, on a 26,000-year cycle.
« Last Edit: 02/17/2012 03:50 am by Proponent »

Offline kevin-rf

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Re: Spacecraft navigation and celestial equator
« Reply #4 on: 02/17/2012 02:11 pm »
So once you leave earth, you have a completely different coordinate system.
If you're happy and you know it,
It's your med's!

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