What: AstroFriday's “September Deep-Sky Extravaganza”

When: San Juan College Planetarium, 4601 College Boulevard, Farmington

Where: The two planetarium shows are at 6:30 and 7:30 p.m. on Friday. The public stargaze begins at 8:30 p.m. in the courtyard behind the planetarium.

Cost: Free. There is a maximum seating capacity of 60 in the planetarium, so seating is on a first-come, first-served basis. The stargaze has no capacity limit.

More info: Call David Mayeux at 505-566-3361 or e-mail mayeuxd@sanjuancollege.edu.

FARMINGTON — Friday at the San Juan College Planetarium, director David Mayeux will be presenting "September Deep-Sky Extravaganza" for this month's AstroFriday event.

The show begins inside the planetarium, where Mayeux will present the different clusters, nebulas and galaxies that can be observed during the fall months. Besides deep-space objects, he will demonstrate where to find the moon and planets in the sky during the evening and morning hours.

After the last planetarium show and barring inclement weather, Mayeux will then lead a one-hour public stargaze using telescopes set up in the courtyard behind the planetarium. Binary star targets for the evening will feature the spectacular Albireo in the Northern Cross, the "double-double" stars Alcor and Mizar, and the north star Polaris, which is also a binary star.

"With the naked eye, you actually see the single star (Polaris)," said Mayeux. "But with a telescope, you can see a dwarf companion. They're both orbiting a common center of mass located between them."

Mayeux said there are some deep space objects that can be viewed without the aid of a telescope.

"You'd be surprised which objects are visible to the naked eye," he said.

Mayeux explained that stars can be single systems, like our Sun, but can also be binary systems or smaller groupings, like the Pleiades system. Then there are the giant star clusters, which when viewed through a telescope, resemble a circular globe made out of countless numbers of stars.

"Star clusters typically have between 100,000 to one million stars in them that are orbiting a common center of mass," he said. "You can think of star clusters as a solar system made up of millions of stars. The globular cluster M13 is the granddaddy of star clusters."

The Andromeda Galaxy, or M31, is another object Mayeux will be talking about and attempting to allow visitors to view at Friday's stargaze.

"Andromeda is the farthest object in space that the unaided human eye can see," he said. "It is two-and-a-half million light years away, and it looks like an oval smudge. With a telescope, you can even see two little satellite galaxies orbiting around it."

Leigh Black Irvin covers health for The Daily Times. She can be reached at 505-564-4610 and lirvin@daily-times.com Follow her @irvindailytimes on Twitter.