Instead of gazing at stars at this Saturday’s star party at McFarland Park, amateur astronomers gazed at artificial satellites that people have put into orbit around Earth during the last 45 years.

Star parties follow the monthly meetings of the Ames Area Amateur Astronomers in the spring, summer and fall, said Drew Sorenson, president of the club.

The club meets at the Story County Conservation Center at McFarland Park, northeast of Ames at 56461 180th St.

About 20 people attended Saturday’s program on satellites, presented by Ames Area Amateur Astronomers member Jake Ewalt.

Ewalt began his talk by leading the group outside to try to view one of the satellites in the “Iridium constellation.” The satellites are leftovers from a failed attempt by the Iridium Satellite company at creating a global satellite telephone service in the late 1990s.

After about five minutes in the cold, the group conceded it was too cloudy to see the satellites pass overhead that night and moved back indoors.

One or two satellites in the Iridium constellation are visible almost every night, Ewalt said. They can be seen with the naked eye at a specific moment when they reflect sunlight.

They appear very bright for about 30 seconds, acting like a mirror moving briefly through the sunlight. “You have to be in the dark and the satellite has to be in sunlight,” Ewalt said.

The Iridium constellation got its name because it originally had 77 satellites orbiting the earth, just as 77 electrons orbit the nucleus of an iridium atom, he said. To an observer, the satellites appear to move through the sky at the same speed as an airplane, he said.

However, the object is an airplane if it has green and red colored lights, strobe-like flashes or if it moves east to west, Ewalt said.

Tracking satellites through the night sky is a fairly new hobby.

“There wasn’t anything to look at 45 years ago,” Ewalt said.

Russia sent up the world’s first artificial satellite, Sputnik, in 1957, he said. Sputnik re-entered the atmosphere in a matter of months.

The Internet has made it easier for amateur stargazers to observe satellites that orbit the earth today, including the international space station and satellites in the iridium constellation, by providing charts of the night sky and other information needed to locate satellites, Ewalt said.

About 70 families belong to the astronomy club, which is more than 20 years old, Sorenson said.

Members of the club have a variety of interests, and monthly topics reflect the areas of expertise of the members who volunteer to present, he said.