by Abby Bielagus

When Philip Sadler took his seventh and eighth grade science class to the Boston Museum of Science Planetarium, he had no idea the field trip would be a life-changing event. The students of the Carol School in Lincoln were so impressed by the astronomy lesson that afternoon in the 1970’s that they returned to school asking for a planetarium of their own.

Sadler, an astronomer himself, immediately went to work with his students, brainstorming designs for a low cost planetarium they could build. The result a couple years later was the Star Lab, the first portable planetarium.

Today the Star Labs are manufactured in Somerville by the family owned and operated company Learning Technologies and sold worldwide.

“Essentially our company began as a school science project,” said Philip’s wife Jane Sadler, president of Learning Technologies.

For close to one year in the early 1970’s, Philip Sadler and his students experimented with various materials they believed were suitable to build a planetarium’s structure. Nothing was working, she said.

Then one day, Philip drove through the MIT campus and inspiration struck. Covering MIT’s tennis courts was a big inflatable dome. Using this cover as an example, Sadler went back to work redesigning and produced the Star Lab’s original design which is still used today, she said.

“Not much goes wrong with them. Models from the original Star Labs made in the early eighties are still out there being used,” Sadler said.

Once the planetarium’s inflatable dome structure was complete, Sadler said her husband went to work on a projector that could cast the image of the night sky onto the dome’s walls. “At that time, there were no inexpensive planetarium projectors, they were either like toys or else they were extremely expensive machines.”

Philip invented an affordable and sophisticated device that uses interchangeable cylinders made of photographic film. “Surprisingly a cylinder projects on a circle and because the cylinders are all made photographically, we can easily produce many, many different images,” she said.

In 1977, Philip secured patents for the Star Lab’s dome, projector and cylinders. He and his wife, also a former teacher, left the classroom setting behind to start a company that would produce these one of a kind portable planetariums, she said.

But that does not mean that Philip and Jane really gave up teaching.

Today, as a result of their invention, approximately twelve million people per year are able to see the night sky the way the ancient Egyptians saw it.

Students learn about celestial navigation not just by reading about it in a text book, but by actually seeing it played out in the stars around them.

The Star Lab looks like a giant silver bubble with a silver tube growing out of one side. Visitors enter through this silver tube which serves as the entrance tunnel. The dome comes in two sizes, the standard dome seats about thirty people and the giant accommodates around sixty. A quick walk through the tunnel and people are transported from their environment to a dark and quiet world filled with stars, constellations and galaxies all around and above.

For 27 years, Learning Technologies has been manufacturing the Star Labs for schools, museums, science centers and other educational institutions.

Everything from the promotional materials to the Star Lab’s cylinders and dome are made at the facility on 40 Cameron St. in Somerville.

One employee, Bruce A. Bloomfield said he has been with the company for 25 years. It is his responsibility to make the cylinders that are fitted on the projectors. He sits at a work bench with a piece of flat photographic film before him. He hand-colors the image and when it is complete, glues it into a cylinder shape.

Near Bruce’s work station is the woodworking shop, down the hall the projectors are made and in another area commercial fans are adapted for their task of inflating of the domes, he said.

In the very back of the building is the packing and shipping area. The atmosphere throughout the building is relaxed and void of the sound of heavy machinery. Mostly it is just people, sitting at desks working on computers or sitting at work benches, building things with their hands.

Walking among the homes on this quiet residential street, one could quite easily walk right by Learning Technologies’ discrete building, completely unaware of the planetarium systems being made inside.

“Occasionally someone will walk in off the street and ask what we’re making and then ask if they can buy something,” Jane said with a smile.

“We aren’t really set-up as a retail shop, but if someone wants to buy a telescope or something we will sell it to them,” she said.

The Star Labs are generally sold to schools, museums, science centers and other educational institutions. A museum or science center will purchase a Star Lab and bring it around to schools or community outreach programs to arouse people’s interest in astronomy. Or a school system will purchase one or several, depending on the demand, and the entire lab is then moved from school to school.

An extensive line of cylinders and corresponding curriculums developed by Philip and teacher consultants make it possible for Kindergarteners and college students alike to benefit from lessons learned inside the dome.

“The incredible part of this product is that the teachers who use it, use it in ways we never dreamed of. They love to adapt the curriculum we provide to their own uses. It’s a real community of educators that use this product and they love to share their ideas,” Jane said.

Recently, Learning Technologies created a newsletter to make it easier for teachers and educators to swap ideas and share helpful hints.

The Sadlers’ and their staff of manufacturers and teacher consultants are constantly developing new astronomy products and Somerville’s community continues to be supportive. “This is a great space for us,” Jane said of the company’s move from Cambridge to Somerville in 1996.

“I didn’t want to work in an industrial section of Cambridge because this is a low-tech operation. A lot of our manufacturing is done by hand, there is nothing messy or noisy about the work that we do. I knew we could fit into a residential area,” she said.

The Sadlers have done more than simply fit-in. They have earned the respect of educators, scientists and astronomers across the world and have become influential individuals in their field. In addition to raising a family, Jane is the president of Learning Technologies and Philip is the director of the science education department at the Harvard Smithsonian Center for Astro-Physics.

Philip still acts as the brains behind the company’s new technologies. “He is the one who comes up with the ideas and helps us do the research and development on new projects,” Jane said.

“His role is a bit more limited now, for him it’s nights, weekends, and summers,” she said.

But he still plays the role of inspiring educator. Once a year, Philip Sadler teaches a class on celestial navigation for the astronomy department at Harvard. He brings a Star Lab out occasionally to aid in his instruction of star navigation, she said.

Sometimes, students in his class will see the Star Lab and excitedly recall the first time they visited one when they were in fifth grade or in high school. Students have told him that it was this trip to a Star Lab when they were young that made them want to be astronomers. Apparently, Philip is not the only person who has attended a field trip and it has become a life-changing event.