Below this answer to Why are Delta Aquariids “for the southern hemisphere” while the Perseids are “for the north”? I wrote the comment:

+1 To make this complete, Comet Swift-Tuttle has a nearly circular orbit of about 1 AU but an inclination of 113.45° which is just about what it would have to be (double) to push the Perseids' radiant to a declination of +58°.

Now I'm thinking that a vector that points toward's a meteor shower's radiant is just the vector sum of the Earth's orbit's velocity vector and the velocity vector associated with the orbit of the shower's associated comet at their intersection point where the shower is a maximum.

Question: If that's the case, is there a simple set of equations for the position of a meteor shower's radiant point and a source for them that can be cited?

It seems like this would have been done quite a long time ago and should be found in some classic early work!

For additional reading and resources about the relationship between a meteor shower and it's associated comet's orbit, see:


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