NavList:

Rob van Gent, you wrote:
"The AI response appears to be based on the CONJUNCTION of Venus and Jupiter in right ascension which indeed gives a different time and angular distance compared with those at the time of CLOSEST APPROACH. I guess that AI does not know the difference."

What fraction of humans know the difference? Maybe one in a 100,000?? Or only one in a million?? This isn't an excuse for the A.I. tool not getting it right since, among the many differences between human intelligence and the current flavors of artificial intelligence, A.I. has vast resources and vast stores of relatively trivial facts "at its fingertips" in endless disciplines of human endeavor. An A.I. tool should at least ask about the specific definition. Then again, the right answer depends on the audience. Ya gotta read the room! 

Among human fans of positional astronomy (a subset of a subset), there is some disagreement over conjunctions. The traditional definition for many centuries up until about the 20th century was conjunction in ecliptic longitude. I still favor that for conjunctions. In much of the 20th century, conjunction in right ascension seems to have been more popular at least in astronomy (as opposed to astrology). I suspect that this was driven by the available published astronomical data. Ecliptic coordinates of planets became less common. But as inexpensive computation became available in the past forty years, suddenly we have options, and the "new" popular (popularized?) definition of a conjunction frequently asks for smallest angular distance.

The "smallest angular distance" also adds new details to the question. Antoine Couette, when he posted the question, asked about "geocentric" angular distance. That's a good detail, and note that it also implicitly suggests we're not interested in observers in space or on the Moon (maybe something to consider for conjunction lists in future decades!). But for visual angles seen by observers on Earth, should we be talking also about the "center of light" for Venus at least? And maybe we should calculate limb to limb distances? And if we do, what is the real limit on the accuracy of the angles, given the "fuzzy" atmospheres of the two planets?

Frank Reed