NavList:

Frank,

I'm not exactly sure why, but your response caused me to wonder if one could use a [modified?] "Snellius construction" with nearby and/or really far away "stuff" to fix the position of an interstellar spacecraft. Of course, no one knows what a "Snellius construction" is* - I sure didn't until I stumbled onto it during my early celestial self-education. So, if you click here and scroll down about halfway, you will find a description. Basically: if you know the actual distances between three objects, you can fix your position by measuring the apparent angles between them.

My instinct tells me this is possible. The only thing I'm having trouble wrapping my mind around is whether or not it is possible in 3D. Would the circles become spheres? If so, the intersection of two spheres is apparently a circle. Would one more point of reference be required ... or three? And how helpful would a DR position be in this scenario?

I'm going to meditate on this. But I'd really like to hear your thoughts.

Cheers!

Sean

* Well, George Huxtable knew about it. But other than him, and Willebrord Snellius ... no one.**

** Okay: George, the guy he was responding to and the people who made the website we both linked to ... but no one else.***

*** I think.