NavList:

Dear Paul,

Thanks for the explanations of the clever method you devised into solving this problem.

You concluded with the following :

" However, results are not so good with the Venus / Mars encounter this

year on July 1. My solution with the above method does not converge. I
had to use trial and error to get 3°33'54.342" separation at 07:10:59
TT. My difficulties are probably due to a combination of slow relative
motion which does not fit a great circle well, plus large separation. "

I would think that the actual reason why you did not and could not find an "easy" solution is simply the one earlier indicated by Robert H. van Gent here on the very onset of this thread :

" Venus will attempt to overtake Mars in the last weeks of June this year but then pull away again. "

My own solution does not converge either and it is a very precious clue that "something unexpected" (Venus starting to pull away from Mars here) is happening.

Best Friendly Regards,

Antoine