In Schubert's "Nachthelle", for tenor solo and male chorus, there is a section in the soloist's melodic line that have, apparently, divisi (upper melodic line, in the photo). Why? Is of soloist's choice to sing one way or another? Below is a shapshot of that section. Thanks.
P.S. Please someone creates "divisi" tag.
Edited: here is the link of the original file (public domain), in the IMSLP: link here
I wouldn’t call it divisi unless two instruments were playing it. Without seeing more of the piece, my first guess is that you’re right and the lower pitch version is for singers that don’t feel comfortable with the high Bb.
Another possibility is only if this section is repeated. It’s possible that the singer is supposed to sing it one way the first time and the other way on the repeat.
A third possibility is that versions of the score are inconsistent at this part, and the editor decided to notate both versions for editorial completeness (this is especially likely if it’s a critical edition).
In any of these cases though, I would usually expect a bit more explanation, such as, in the first possibility, the word “ossia.” As written, it’s definitely more mysterious than it needs to be. I’d look around and see if there’s an editorial explanation in the preface, or an explanatory footnote, or something like that.
