The year was 2003. Jeffrey Alexander stood in line to look through a telescope on the roof of the garage of the Museum of Science. Mars was passing particularly close to earth. He, along with many others, wanted to see it. It tickled his fancy, he says, that so many people were excited to gather for this celestial event.

In 2005, Earth and Mars were due to be close to each other again. Alexander, who had recently moved to Arlington, decided to have a viewing party at Robbins Farm Park. He teamed up with Friends of Robbins Farm Park, the Arlington Recreation Department, and some locals with telescopes to make it happen. Over the next 2 years, he threw a couple more stargazing parties. Leslie Mayer, a member of the Park & Recreation Commission, suggested that Alexander should start a regular series of stargazing events so it would be easier to get permits from the town. And so Arlington Astronomy Nights was born.

For 11 years now, Alexander has hosted 4 or 5 Arlington Astronomy Nights every summer. At its busiest, 70 to 80 people might show up. Astronomy Night is popular with parents and their kids, but amateur astronomers and passersby of all ages come to look through Alexander’s telescope.

“Plenty of teens in the park want nothing to do with us, but some take a peek and will allow themselves a little sense of wonder at the world that they’ve been socially molded to pretend doesn’t move them. If they’re like me, they can’t help but feel a brief sense of the smallness and insignificance when gazing at objects vastly, incomprehensibly larger than themselves,” Alexander says.

This past Saturday was the last Astronomy Night planned for this summer. Clouds covered up the moon and Jupiter, the night’s main features, but Alexander entertained the crowd by sharing a map of the moon with them, showing them Zakim Bridge in Boston and the stars Mizar and Alcor in the constellation Ursa Major through the telescope, and handing out glow sticks.

There’lll be more Astronomy Nights next summer. Those interested in attending future stargazing events can sign up for Astronomy Nights emails online. Mars will be having another close approach with Earth next fall, too.

Alexander, who studied computer science in college, now leads a software team at Oracle Labs. Astronomy may be a hobby for him, but it’s easy to tell from the way he talks about it that it’s close to his heart and he loves to share it with others.

“There’s really nothing better than the exclamations I hear and expressions I see on peoples’ faces the first time they look through the telescope,” he says. “Sharing the passion that I have for observing the night sky, even if just for a moment at a time, makes it worth doing year after year.”