PORTSMOUTH — It's a clear and cold winter evening in Market Square, and Ted Blank is just getting warmed up.

With the sky serving as a textbook offering a window onto the past, present and future, he transforms the brick walkway around him into a makeshift classroom.

Together with his telescope, the Hampton resident issues a friendly greeting to all who pass by and offers them a chance to see the stars.

"Did you know that sunrise on the Moon takes place in slow motion?" he suggests as a passerby begins to become curious.

"If you were standing on the Moon it would take the Sun seven Earth days to climb from your Lunar horizon to a point straight overhead," he finishes as the passerby becomes hooked.

On any given night — cloud cover permitting — Blank can be found on a sidewalk in the Seacoast gazing at the universe above. Conducting what has come to be known as "sidewalk astronomy," Blank is one of a dozen other amateur astronomers across the Seacoast who volunteer their time to educate the public. Unlike scheduled gatherings and coordinated viewing sessions at local observatories, Blank said he doesn't just wait for you to come to him, he seeks you out.

By day the 58-year-old amateur astronomer works at a software company, by night he is, to use his preferred description, a "guerrilla astronomer."

As a member of the New Hampshire Astronomical Society, he dedicates his personal time to the nonprofit's mission by providing public outreach and education to all comers. Having been a member for the past three years, he carries out the society's mission along with other local members such as Jim Moe, Herb Bubert, Tim Mauro, Tom Cocchiaro and others.

For example, over the past year, Blank said, the NHAS has offered assistance to local libraries to obtain and maintain a 4.5-inch reflecting telescope that can be checked out like a book. Blank said the program has been very well received, in part due to club members volunteering to "adopt" a library scope and try to visit it once a month or so to provide any needed maintenance.

Aside from sponsoring free Sky Watch activities at schools and libraries across the state, Blank said his fellow astronomers make it a point to hit the pavement.

"We realize that it's fun to go where people are," he said.

Despite there being considerable light pollution in places like downtown Portsmouth, the Hampton strip or even outside the Fox Run Mall in Newington, Blank said it's amazing what you'll find by simply looking up.

"There are still some beautiful things you can see from downtown areas," he said. "Viewing in real time through the eye piece gives people an understanding that planets are not infinitely far away or infinitely hard to understand."

As a volunteer for the NASA Solar System Ambassador program, he said his passion for educating others is all about the response he gets from the curious passers-by who stop to take a glimpse into his telescope.

"The opportunity to show them the wonders of the universe with their own eyes is priceless," said Blank. "I enjoy the sights, and I also enjoy sharing them with folks who maybe haven't ever looked through a telescope, or those who did so as a child but may have forgotten what a thrill it is to see Saturn's rings, Jupiter's moons, or the craters on our own Moon with your own eyes."

Whether it be a child staring up at Saturn's rings or a grown-up staring directly at one of Jupiter's moons, the response is almost always positive, he said.

"We get absolutely wonderful responses," he said. "Some say 'this is the best thing that has happened to me all day' and others say 'I've never looked through a telescope before, this is wonderful.'"

Much like painting a portrait on the end of a telescope, Blank said there are wondrous things to be seen.

"The rings of Saturn are the prettiest thing in the solar system," he said.

The gratification, said Blank, is the fact that he and his other sidewalk astronomers are able to show people the stars without having to use the Internet, batteries or television.

"This is free every night the sky is clear" he said.

Having gotten involved nearly three years ago, Blank said it all started with the purchase of a small telescope.

"I had no idea of what to do with it," he said.

The next step was to join an astronomy club. Blank said there are several in the area. In addition to the New Hampshire Astronomical Society, www.nhastro.org, there is the Massachusetts-based North Shore Amateur Astronomy Club, www.nsaac.org, and the Amateur Astronomy Society of Northern New England, www.asnne.org, based in Kennebunk, Maine.

"All are made up of dedicated volunteers who will be happy to help your school or club set up an educational and fun event," he said.

The NHAS for example has more than 2,000 loner telescopes to try out for free, Blank said.

"We encourage them to try and learn about it and make their own informed choices," he said.

Another fixture in the Seacoast for public outreach and astronomy, according to Blank, is Durham resident John Gianforte.

Gianforte is a physics professor at the University of New Hampshire and teaches astronomy at Granite State College. With his own observatory at his house, he also helps conduct free public observing sessions at the UNH Observatory on first and third Saturdays monthly. The session are often filled, whether with children or other professors.

"We really have good sessions," he said. "The conversations are so stimulating and are about a wide variety of philosophy and astronomy. We all learn from each other."

University students even get in on the action.

"Sometimes entire floors of dorms come to the public session," he said.

Gianforte said he really appreciates what people like Blank do in giving their free time to educate others.

Calling it "very important work," Gianforte said he believes becoming engaged in astronomy and developing a general understanding of the solar system is vital these days.

"If the general public understands this better, then they'll be able to know if someone is feeding them bologna," he said. "What you don't know can really hurt you nowadays."

Sightseeing outside the planet Earth is in many ways like hiking to the bottom of the Grand Canyon. By the time the hike is over, the amount someone has learned about the environment is endless, Gianforte said.

The year 2009 was the 400th anniversary of Galileo making his first telescopic observation, Gianforte said.

This year — from Jan. 7-13 to be exact — marked another 400th anniversary — Galileo's discovery of the four major moons of Jupiter with his homemade telescope, Gianforte added.

Also, 400 years ago this month and almost to the day, Gianforte said, Galileo published his observations of the Moon and beyond.

"That completely revolutionized our way of thinking," he said. "It deeply provincialized humans in the universe. We realized we're just another planet that happened to orbit the Sun. Galileo brought on the whole genre of telescopic observation, astronomy and scientific method. He is responsible for a whole shift in how science taught us about the world we live in."

He said he understands people have a lot of things going on and recognizes the lure of the modern world.

"When the power goes off all hell breaks loose and we're left stranded and complaining," he said. "People complain and say 'I don't have my TV to watch,' and yet we are so interconnected with nature and the universe itself."

Connections are something he and his fellow astronomers like Blank say they hope to achieve.

"What goes on out there in Space has profound effects on life on Earth," Gianforte said. "You don't have to dig very deep to discover the connection."

In his opinion, the future of humanity depends upon understanding life beyond our own.

"If humans are going to survive into the long-term future, we're not going to do it because we're strong," he said. "We're going to do it with our intellect, and it needs to be used to investigate the world around us."

For Gianforte, the fact that an astronomer can look out into the universe with the biggest telescope imaginable — nearly 12 billion light years away — and not find another single trace of life is the most amazing thing of all.

"We are the only ones we know about and the only life we are aware of," he said. "How can we spend one more minute and dollar trying to kill each other?"