How great is that conjunction?

December 19, 2020 9:34 AM

How does the upcoming great conjunction compare to others of the past or future?

The above link has more info than most articles, but I want more detail. For the last/next 10,000 years, what is the largest angular separation at conjunction? The minimum? Is there a plot of how it changes every 20 years?
What tools can I use to answer these questions myself?

posted by stobor to Science & Nature (5 answers total)

Best answer: This Wikipedia page has a table of every conjunction between 1200 and 2400 AD, and the one after it lists some of the smallest-angle conjunctions between 1793 BC and 4523 AD. The largest separation in that 1200-year period is about thirteen times farther than this year's conjunction, and the smallest is about a third as far.
posted by theodolite at 12:39 PM on December 19, 2020 [1 favorite]

Best answer: It's hard to expand this to 10,000 years. The Wikipedia page for XEphem links to more information about the model they use for planetary calculations.

If I were trying to generate this for myself, I would probably start with XEphem.
posted by inexorably_forward at 12:52 PM on December 19, 2020

Best answer: You can use PyEphem for this.
posted by vacapinta at 1:19 PM on December 19, 2020

Response by poster: Oh wow, I checked Wikipedia last week and I don’t think the chart was there then.
Thanks for the links!
posted by stobor at 2:22 PM on December 19, 2020

Note that the Wikipedia page is only for Jupiter-Saturn conjunctions.
posted by Hatashran at 3:12 PM on December 19, 2020