When she was younger, Christina Diebold looked forward to the start of every school year.

“I always liked to learn,” she says. Now, at 77 years old, the Bangor resident can hardly wait to sign up for classes each fall through Penobscot Valley Senior College.

At 17 senior college campuses around the state, from Fort Kent to York to Belfast to Bethel, Mainers in their 50s and beyond like Diebold are registering for courses, gathering up their notebooks and heading back to the classroom — or the golf course, or the art studio — to learn for the pure joy of learning.

The low-cost, non-credit courses offered through senior college won’t help complete a formal academic degree. Even more academic courses like “American Women’s History” or “Topics and Research in Psychology” won’t earn these students a single unit of credit, though they may be taught by respected scholarly experts in their fields.

Instead, these classes, typically six weeks in duration, often including field trips and guest speakers, pay off in more personal ways. For one thing, there are no tests or final papers, so students can relax and enjoy the experience.

“I always wanted to take a course in astronomy, but I was never good with math so I didn’t dare to,” Diebold, a retired Bangor Daily News copy editor, says. “But with senior college, I can learn about astronomy without all the angles and equations, without any tests or grades.”

The attraction also is social, points out Dee Virtue, also 77, of Orono, retired from her long career teaching high school biology. “A lot of older people live alone, and this really gets them out to socialize,” she says. “You meet all kinds of people you’d never meet otherwise.”

And, adds Dara Perfit, 73, of Hampden, the golden years are “give-back time.”

“Those of us who are lucky enough to be healthy and engaged can give back to our communities with our ideas,” she says. Like Diebold and Virtue, Perfit not only takes classes through Penobscot Valley Senior College but also serves on the Bangor organization’s curriculum committee, helping to design and facilitate each year’s wide-ranging roster of courses.

Across the loose-knit statewide network, with course titles, such as “The Fisherman and His Quest,” “Some of My Most Exciting Opera Memories” and “Beginning Golf,” the system runs almost entirely on volunteer energy. Even the most venerable lecturers and class leaders aren’t paid. As such, course offerings at each campus reflect the interests and expertises of regional residents with a knack for sharing their enthusiasms.

At Sunrise Senior College in Machias, for example, where the mission is “to provide intellectual stimulation, practical knowledge, social interaction and fun to people 50 and older and their spouses or partners of any age,” students can participate by live videolink in the respected Camden Conference, a community forum on global issues. The topic this year is “Africa Rising.” Or they can learn artisanal bread-making, study American short stories or learn what it was like to grow up in colonial-era Congo.

Up in Fort Kent, students at St. John Valley Senior College can bone up on gall bladder disease, beekeeping or the history of cinema. And at Coastal Senior College in Camden, fall courses explore environmental policy in Maine, early Celtic spirituality and the art of the memoir.

Many of these subjects can now be learned online, acknowledges Program Manager Anne Cardale, whose part-time position is supported by the University of Southern Maine. “But you miss so much without the discussion and the interaction of a classroom,” she says. “Maine’s rural areas can be quite isolating; senior college is a chance to come out and make a new friend.”

The Maine Senior College Network was founded in 1999 through a one-time appropriation of the Legislature. Now, each of the 17 campuses runs independently, with administrative support from Cardale’s office.

“Each campus is different, and each one has its own volunteer board that decides everything,” Cardale says. “But the amazing and wonderful thing about the senior college network is that without the volunteers who teach the courses, it wouldn’t exist.”

Some courses feature several different presenters, such as a popular series in Bangor called “Living on the Penobscot: People, Places and History,” which this fall will bring in six different experts to explore various aspects of the river’s cultural impact.

Virtue, the Orono biology teacher, is on tap to teach “DNA for Beginners” this fall, one of several popular courses she has taught in the past. “It’s one of my favorite courses,” she says. “For the most part, senior citizens don’t know much about DNA, because most of the research has developed since the mid-1970s and we’ve made such huge advances since then. Now there are practical applications in agriculture, medicine, criminology and other areas.”

Virtue says teaching seniors is fun. “Having spent most of my career teaching 15-year-olds, most of whom would not be in my class if it weren’t a requirement for graduation, it is a joy to teach people who are actually interested and are there because they want to be,” she says. “Also, they are never rude, and there are no behavior problems. Every time I finish a class I’m flying high because people are so appreciative.”

The cost of taking classes through senior college is minimal: An annual membership costs between $25 and $35, depending on the campus, plus there’s a modest tuition of $15 to $30 for each class. Scholarships are available. Each campus has its own schedule, but all are preparing to open registrations now. To learn more about the Maine Senior College Network visit maineseniorcollege.org or call the network office at 780-4128.

Meg Haskell

Meg Haskell is a curious second-career journalist with two grown sons, a background in health care and a penchant for new experiences. She lives in Stockton Springs. Email her at mhaskell@bangordailynews.com.