Little Shop Question

This is such a minor thing, but it's been killing me to understand this. I recently saw a production of Little Shop of Horrors and looking through their promotion for it, they gave this random fact that the intro for the stage musical and for the movie are slightly different. In the stage version (from the 82' off-Broadway to any production now), the eclipse happens on September 21st, but in the movie the date is September 23rd. I've really tried looking for more information and the only sources that talk about it just raises the question and then never answers it. I've really not been able to figure out the odd, yet specific change. Anyone out there know?

Updated On: 3/31/19 at 09:59 PM

That is definitely on the right track, the only problem with that is the September Equinox is rarely on the 21st, pretty much only on the 23rd (the 22nd only on leap year). For 1979, 1982 (when the show premiered), and 1986, all those equinoxes are on the 23rd. The show never gives an exact year, just the "early 60's", but if it's taking place in either 1960 (when the original movie was made) or 1964, the equinox would be the 22nd making the eclipse then be taking place on the last official day of summer.