The moon is expected to be a black disc in the Monday afternoon sky as it moves in front of the sun in Maine’s first total solar eclipse in more than 60 years.

Many of the state’s communities are now national, if not global, destinations for the astronomical event that experts say will enter Maine in the upper corner of Oxford County and leave the United States near Houlton in Aroostook County.

The whole eclipse – starting when the moon begins to obscure the sun – is expected to last about 2 1/2 hours, and totality should last minutes, beginning at 3:28 p.m. on the western side and ending at 3:35 p.m. on the eastern side.

A total solar eclipse occurs when the moon passes between the Earth and sun, blocking direct sunlight for a short time.

Totality is the moment or duration of total obscuration of the sun or moon during an eclipse. In astronomy, obscuration is the concealment of a celestial body by the passage of another between it and observers.

Rangeley is among several communities expecting many residents and visitors to gather for the eclipse. Town Manager Joe Roach said the town in Franklin County has been planning for the event for more than six months.

“Folks are really excited to actually witness the eclipse,” Roach said. “There’s also some anticipation or curiosity about how busy it really will be. We won’t really know until (it happens). We’re feeling pretty good about the preparations we made, and we’re flexible and ready to respond as needed.”

Roach said Rangeley has borrowed a Maine Department of Transportation traffic camera in anticipation of the heavy traffic leading up to the eclipse. The Franklin County Emergency Management Agency said as many as 20,000 people could be headed to the Rangeley Lakes Region.

The camera is set up at one of the town’s busier intersections, and periodic checks have shown mostly normal traffic, Roach said.

Town departments have been busy posting roads and otherwise preparing for the celestial bash – the Shadow of the Sun Festival. The celebration began Friday and features nearly a dozen events.

Reservations for landing and departure at the Stephen A. Bean Municipal Airport in Rangeley have maxed out at 11 aircraft, Roach said.

Safety ahead of the event has been key, with many town departments and state agencies implementing plans over the past several days. Franklin County Sheriff Scott Nichols said Wednesday his department expects to have a heavy presence Monday in the Rangeley and Carrabassett Valley areas.

Along with local and county emergency workers, the Maine Warden Service is expected to have a presence on and around popular trails that might call to the more adventurous, according to Mark Latti, spokesperson for the Maine Department of Inland Fisheries & Wildlife. Wardens plan to bring a variety of equipment, including trucks, snowmobiles, airboats, hovercrafts and all-terrain vehicles, he said.

“We are moving resources from the southern part into the path of totality area,” Latti said, “and that includes game wardens and supervisory staff, in areas such as Rangeley, Greenville, Jackman, Millinocket and Houlton.”

Most people are likely enjoy the total solar eclipse from viewing spots on or around paved roads, he said, but there are some likely to wander for that perfect spot.

“(Some) will want to see it from a more remote area, and want to hike in, drive on a logging or dirt road, venture out on a somewhat frozen lake,” Latti said. “We are prepared and will be available for search and rescue for anyone who may become lost, stuck or injured during that time period.”

Greg Cornwell, a meteorologist at the National Weather Service office in Gray, said the main concern is making sure motorists are careful with the melt-off from Thursday’s snowstorm.

Nichols shared similar concerns after a Sunday afternoon visit to the Rangeley and Carrabassett Valley areas.

Cornwell said the weather looks good for Monday afternoon, with sunny skies and temperatures in the high 40s or low 50s.

“Overnight (Sunday) into (Monday) morning, there might be some valley fog or low clouds that develop, but that should dissipate by the time eclipse time comes around in the afternoon,” Cornwell said. “It does look like we might have some higher-level clouds approaching in the afternoon from the southwest, but you should still be able to view the eclipse pretty well.”

Those traveling Route 4 might also consider stopping at French Falls on French Falls Drive in Jay for the Great American Eclipse Party from 2:30 to 4:30 p.m. The Spruce Mountain High School Envirothon team plans to offer guided hikes, activities and demonstrations during and around the eclipse.

Junior Lily Fortier said her team of five, one of four teams at the school, has been learning about eclipses and planning since January for Monday’s total solar eclipse. She said adviser Rob Taylor, the school’s physics and environmental science teacher, STEM (science, technology, engineering and mathematics) mentor and Envirothon and robotics adviser, made clear to students the rarity of the event, she said.

“The last total solar eclipse to pass over Maine was in 1963, and the next total eclipse to pass directly over Maine isn’t until 2079,” Fortier said. “We had a workshop in February where we taught all the teachers in the district about the eclipse. This is also when we started our fundraiser – selling eclipse glasses.”

The glasses might be sold out, Fortier said, but activities planned for Monday afternoon include making eclipse viewers out of cereal boxes.

Fortier said her team is equipped with a wealth of information about the total solar eclipse, including that people are not the only creatures likely to be affected.

“The eclipse can also confuse nocturnal animals,” Fortier said, “so there can being sightings of animals we generally wouldn’t see during the day.”

The University of Maine is planning to livestream the eclipse from the school’s high-altitude balloon beginning at 8 a.m. The livestream is to be available on YouTube.

NASA is also planning to livestream the eclipse at nasa.gov/nasatv.