In a descriptive sense, the star did fall—across the sky.
It's a somewhat uncommon expression, but to say that they held spectacle to its descent means that they observed the spectacle of its descent.
Typically, shooting stars are associated with blessings and well-wishes.
A variation of this (one that is more transitive) would be something like:
She was in awe at what she was held spectacle to.
Of course, it need not be positive:
She was aghast at the horror of what she was held spectacle to.
From Merriam-Webster's definition of spectacle:
1 a : something exhibited to view as unusual, notable, or entertaining
especially : an eye-catching or dramatic public display