As the sun sets, dim stars glow more brightly and others appear, arraying into familiar constellations.
Tom Fleming uses a laser pointer to identify them for his Astro 203 class.
Here is familiar Orion, the hunter. Here are lesser-known Cassiopeia and Pegasus and Perseus, neighbors in the night sky and forever linked in Greek myth.
The title of the course is "Stars." The subject is vast and the instructional theater is the dome of Flandrau Planetarium where, every Tuesday and Thursday, 135 students fill the reclined seats to journey across the universe and learn some science.
"Stars" is one of six general education courses offered each year by the University of Arizona's Department of Astronomy - the only courses in Fleming's department that don't require a knowledge of physics and calculus, he said.
They are opportunities for students in fields such as business and the humanities to expand their views of the universe and to fulfill the requirement for science courses in the curriculum.
McKenzie Storey, a pre-business major, said she has always loved astronomy and took this particular course when it was offered in a traditional classroom. "It was cool, but it wasn't nearly this cool," she said. This year, Storey is a teaching assistant to Fleming.
Having Flandrau as a classroom is a bonus, said Fleming, and the only drawback is the comfort of the reclined seats, which will sometimes lull students to sleep in the darkness.
Tommy Verley, another business major, said before Tuesday's class that he expected to stay awake, but only because "I had a lot of coffee this morning."
Verley signed up for the course on the advice of his older brother. The concepts in the initial class were complex, he said, but presentation of them in the planetarium "made it a lot easier to understand."
On Tuesday, Fleming used computer animations of the Earth's rotation and orbit around the sun to explain the seasons, toured the night sky from dusk to dawn, and ended the class with a clip from a motion picture.
The climactic scene from "Clash of the Titans" linked Fleming's tour of the constellations with the mythology that named them.
This was not the recent version, but the 1981 movie featuring Laurence Olivier as Zeus. In the film, Zeus' mortal son Perseus rides a clumsy animation of the winged-horse Pegasus to rescue Andromeda from a sea monster.
The old-school animation is fitting. This theater is older than the film. Flandrau's star projector is nearly 40 years old - an analog relic that Fleming and the College of Science would like to replace with the latest in digital projection.
The $600,000 to $1 million cost is "not trivial," as the astronomers say about most everything significant.
Fleming has arranged a demonstration of the new technology for potential donors. He would like to see the UA expand its use of Flandrau as a teaching tool. His department would benefit, of course, but there is software available for chemistry and biology as well.
As class ends and the screen credits roll, none of the students is obviously snoozing.
They emerge from the UA Science Center where Flandrau is housed, squinting and donning sunglasses, surprised by the mid-afternoon brightness of our nearest star.
Contact reporter Tom Beal at email@example.com or 573-4158.