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Solar Astrogation

efkelley

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So, I'm working up a system for astrogation around old Sol here, and I thought I'd drop my notions here for a quick plausibility check.

In order to calculate my position in the solar system by observational navigation, I need three points (say, the sun and the two nearest planets) and my distance from them. From those I can do some trigonometry and figure out exactly where I am. Correct?
 

Lhun

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Correct as in you can calculate your position that way - yes. Correct as in you need all that stuff - no.

In principle you just need a camera and two points. Take a snapshot of the sun, and you have the bearing. Take a snapshot of any other object (with a known location), and you have another bearing. Draw the two lines on the map and you have your position. You can do that even with two stars, though of course you'd need better camera resolution to get the same precision.

Note: i'm assuming you know your general location (as in, which side of the sun you're looking at). Like you can get a GPS positioning with just two satellites, getting two possible locations of, for example italy and the north pole, and then simply checking for polar bears to be sure. If you do not know anything about your location, you'll need the bearing to four objects.
Works like this: Bearing to two objects puts you somwhere on a circle, to three objects puts you on one of two possible points, four objects gives you an exact location.
If you instead calculate from distance, distance to one objects puts you somehwere on a sphere, to two objects puts you somewhere on a circle, to three objects puts you on one of two points and to four objects gives you exact location again.
 
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efkelley

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Gotcha. I had the basics, but thanks for nailing down the specifics.