Millions of school children across North America will have a chance to experience what could be one of the most awe-inspiring events of their lifetimes on Monday: A total solar eclipse, or at least a partial solar eclipse.

Students in the St. Vrain Valley School District won’t be among them.

The district sent a letter to families in March announcing that there would be no classroom activities where students could observe Colorado’s partial eclipse outdoors, even while wearing solar glasses, due to safety risks.

It said students will not be permitted outside for recess or lunch from 11:30 a.m. to 2 p.m. Students who attend class in an outside portable classroom during that time will have to wear certified safe solar viewing eyewear while they walk to and from the main school building.

Students on a bus during that time will have to wear safe solar eyewear on the bus.

“Looking directly at the sun during an eclipse without proper safety eyewear can cause serious and permanent eye damage,” the letter read.

St. Vrain Valley Schools said parents can excuse their children from school to watch the partial eclipse at home. District officials said some classrooms will watch a NASA livestream of the event on TV or their devices and remain indoors from 11:30 a.m. to 2 p.m.

“My reaction is disappointment,” said Jeffery Bennett, a Boulder-based astronomer, teacher and writer, and trained astrophysicist. “This opportunity to see an eclipse like this in Colorado isn't coming again until 2045, and for kids to miss this, to see this thing with their own eyes, it’s really a shame.”

Bennett gives presentations about the eclipse at schools across the country, including talks in several Colorado classrooms to prepare for the upcoming eclipse at schools in Broomfield, Pueblo, Kersey, Boulder and Parker.

One preschool has provided glasses to all children to view the eclipse with a lesson about the world around them. The parent-teacher association purchased special glasses for one middle school in Jefferson County to view the eclipse along with a science lesson – but at least one elementary school in that district is keeping students inside during the eclipse, “exercising an abundance of caution.” It is allowing parents to check kids out of school for viewing.

Bennett is the author of the children’s book “Totality!,” a free digital textbook for middle school teachers. He also developed the free Totality app, which is run by the American Astronomical Society. That app has an interactive map that shows what you’ll see at any location in the world for upcoming and recent past total solar eclipses.

Bennett said even the partial eclipse that will be visible to Coloradans if the weather is clear can be awe-inspiring and magical.

“To realize that's the real light from these distant objects hitting your own retina is a very inspiring experience and I wish that all kids could get this experience,” he said.

He points to a recent NPR story on how the last total solar eclipse seven years ago changed kids. One said: “It just kind of broadened the horizons and perspectives on literally everything.”

The moon is 400 times smaller than the sun. It’s also about 400 times closer to Earth than the sun. When the orbits align between the three bodies, the moon and the sun appear the same size in the sky.

“This allows the moon to completely obscure the solar disk,” said Jimmy Negus, a solar physics research scientist at the Cooperative Institute for Research in Environmental Sciences. “And the shadow from that occurrence is what we see projected onto Earth.”

A total solar eclipse is when the moon’s face completely blocks light from the sun.

Coloradans will only see a partial solar eclipse, during which about two-thirds of the sun’s surface will be covered. But Negus said it will still be quite a show.

“During this event in Colorado, we will see the sun not fully obscured by the moon,” Negus said. “And so, while you might notice some dimming and some shadows, you will never see full darkness like you will with the total solar eclipse. That being said, it's still a wonderful event in nature, and it's still fascinating to see the interplay between the earth, moon and the sun.”

He said observing how animals respond to the shift in the environment is a spectacular sight. For example, birds start to flock and crickets begin to chirp in the middle of the day.

Bennett said Saint Vrain Valley School District typically does great work in science education. He spoke with SVVSD Supintendant Don Haddad this week to see if he’d reconsider, even offering to provide solar glasses for the entire district at a discount price.

The district isn’t changing its mind, but Haddad offered a clue to Bennett as to what was behind the decision. (The district didn’t provide an interview with CPR.)

“He mentioned that they did have all the kids outside in 2017 for the partial eclipse that was visible down here, and he said he then had a couple months of dealing with parents who were calling freaked out about, ‘I think my kid may have looked at the sun,’” said Bennett.

It turned out there were no problems.

“I could see where it's a difficult position for him,” said Bennett. “I do wish they made a different decision.”

NASA does state that for partial or total eclipses, it is never safe to look directly at the eclipse without proper eye protection. But children can wear safe solar viewing glasses or they can experience the eclipse by doing a pinhole projection by poking a hole in a paper or using a colander and looking at the sun’s projection on the ground.

“That works fine, and it's a decent backup,” Bennett said.

Bennett would have preferred that the St. Vrain district cancel school and let children see it with their families. He has encouraged schools across the country to host events and invite parents, “so it becomes a family learning experience.”

He said schools can teach about the eclipse in a variety of ways, including lessons on the celestial cycles, how the spectacular events were viewed in human history and how eclipses drove certain developments in science. There are art projects that can be carried out, or biology discussions talking about the eye as a lens system and how to observe and eclipse without harm. After the eclipse, teachers can ask students about the experience, he said.

Bennett plans to donate the 30,000 solar glasses he offered the district to an initiative to bring millions of them to southern Africa so children there can watch a total eclipse there in the future.

To read more stories from Colorado Public Radio, visit www.cpr.org.