Noctiluca (1974)

Otherwise known as Magellan's Toys #1. Hollis Frampton's "Noctiluca" was a film designed to be shown on the second day of the Magellan cycle, the filmmaker's unfinished magnum opus work. The title (nox/luceo) means something that shines by night, i.e., the moon, and the film indeed consists of a bright sphere, sometimes white, sometimes tinted, sometimes single, sometimes doubled and overlapped.

Unfortunately the movie Noctiluca is not yet available on HBO Max.