The key word is "bright". It's clearer in the other article: https://skyandtelescope.org/astronomy-news/asteroid-will-cover-betelgeuse-may-reveal-its-visible-su

The key word is "bright". It's clearer in the other article: https://skyandtelescope.org/astronomy-news/asteroid-will-cover-betelgeuse-may-reveal-its-visible-surface/ https://skyandtelescope.org/astronomy-news/asteroid-will-cov... > An occultation of a 1st-magnitude star is rare — such an event is visible from Earth only every few decades and > That changed on September 13, 2023: In advance of the December event, Leona occulted another object, this time of a 12th-magnitude star. It makes sense: there are only a few bright (1st-magnitude) stars so occultation of them is rare, while there are a lot of stars in the sky so occultation of some (dim) star is not very rare. ———— Edit: We can come up with a more explicit expression. If each individual star has an occultation once every k days, then "at least one of N stars" has an occultation roughly once every 1/(1-(1-1/k)^N) ≈ k/N days. So if with N=22 (the number of 1st-magnitude stars: https://en.wikipedia.org/w/index.php?title=First-magnitude_star&oldid=1169525927#Table_of_the_22_first-magnitude_stars https://en.wikipedia.org/w/index.php?title=First-magnitude_s... ) this is once in 40 years (say), then with N = 10000 stars you'd see about once a month.