POTSDAM — For 55 years, Frank A. Revetta has gathered with community members to look at the stars.
“You have to let your eyes adapt to the darkness,” Mr. Revetta said Thursday as he began his 56th year hosting free 45-minute shows at the SUNY Potsdam planetarium named in his honor.
In the basement of Stowell Hall, a quiet excitement moved through the Frank A. Revetta Planetarium as about 25 people found seats in the domed room. On long, vinyl benches, people craned their necks toward an illuminated sky.
The show was about to begin.
Opening the 17-week season of spring shows, Mr. Revetta focused on northern circumpolar constellations, which are groups of stars that center around the north star, Polaris, and are visible in the northern hemisphere all year round.
Five constellations are considered northern circumpolar, as they never set below the horizon: Ursa Major, Ursa Minor, Draco, Cepheus and Cassiopeia.
Beginning with Ursa Major, or the Big Dipper, Mr. Revetta pointed to the bowl-and-handle constellation using an arrowed laser pointer. In the north country February sky, at about 44.5 degrees latitude, the Big Dipper’s seven stars can be seen in the clear northeastern sky.
Just west of the Big Dipper, Mr. Revetta said, Ursa Minor, or the Little Dipper, is also comprised of seven stars, including Polaris at the tip of the handle. Around Polaris, all other stars in the northern hemisphere appear to rotate each year because of the Earth’s orbit around the sun.
As the earth rotates, stars appear to also be rotating around a fixed Polaris — the Big Dipper appears higher in the northern sky in the spring, then in the northwestern sky in the summer and near the northern horizon in the fall.
“That’s the first one to find,” Mr. Revetta said of the Big Dipper, as two “pointer” stars in the Dipper’s bowl point west, directly to Polaris.
In between the two Dippers, the tail of a dragon winds its way down toward the horizon, meeting up with the dragon’s body just below the Little Dipper. Draco the dragon seems to crane its own head, as viewers do, west of the Little Dipper near the horizon.
The “royal family” completes the five northern circumpolar constellations: King Cepheus and Queen Cassiopeia.
Situated west of Polaris, Cepheus looks like a simple sketch of a house, with a triangle roof and square base. And next to the king, sits the queen made of five stars, “who always bragged about how beautiful she was” in Greek mythology, Mr. Revetta said.
The winter positions of all stars visible in Potsdam will seem to shift counterclockwise around Polaris across seasons, Mr. Revetta reminded his audience, a mix of families with young children, area students and curious community members.
In next week’s Thursday planetarium show, starting at 4 p.m., Mr. Revetta will cover “North Star (Polaris)” in more detail.