SKY GUIDE: This map represents the night sky as it appears over Maine during May. The stars are shown as they appear at 10:30 p.m. early in the month, at 9:30 p.m. at midmonth, and at 8:30 p.m. at month’s end. Sadly this month no planets will be visible in the evening sky. To use the map, hold it vertically and turn it so that the direction you are facing is at the bottom. Sky Chart prepared by Seth Lockman

The month of May is named for the Roman goddess Maia, who was the mother of Mercury and a daughter of Atlas. May Day, also known as Beltane in Gaelic, marks the half-way point of spring, so it is one of our four cross-quarter days along with our four seasons. The other are Lammas on Aug. 1, Halloween on Oct. 31, and Groundhog Day or Candlemas on Feb. 2.

We have had a cool spring so far following an unusually warm winter. This part of the earth will really start to transform itself this month as the tender young green leaves appear once again on our trees, and cherry and apple trees and magnolias, along with many kinds of shrubbery, will blossom in all of their glory. Many birds are returning from the south and the spring peepers and other frogs are already singing up a storm to add an audible component to the visual beauty of renewal during spring.

The sky above us is also transforming as we lose Orion and most of the Winter Hexagon with only Gemini and Auriga hanging on for another month. All three members of the Summer Triangle – Lyra, Cygnus and Aquila – will be up in the northeastern sky by 11 p.m. by the middle of May.

As the days and nights get consistently warmer, this is a great time to venture outside more often and enjoy some of the many celestial and terrestrial highlights offered during this season. Venus is still catching up with Mars in Gemini as the evening planets, and Jupiter, Saturn, and Mercury are the morning planets this month. There will be a penumbral lunar eclipse during the full moon on May 5, but that will not be visible in the U.S. The Eta Aquarid meteor shower peaks the morning of May 6, but the moon will be very close to full to washout most of these meteors. The most exciting highlight this month will be an occultation of Jupiter by the moon, but you will need a telescope to see it since it will happen at 7:45 a.m., well after sunrise.

Watch brilliant Venus slowly catch up with Mars all month long. They are both in their direct or eastward motion through the sky now against the fixed background of stars. Notice that Venus is just over 100 times as bright as the Red Planet, which is slowly getting dimmer and falling farther behind Earth’s orbit around the sun even as the faster moving Venus is catching up with us and getting brighter. By the end of May, Mars will be just one degree shy of the Beehive open star cluster in Cancer, which is similar to the Pleiades in Taurus, where Mars was a few months ago. Venus will be just 11 degrees to the west of Mars near Castor and Pollux in Gemini. Watch the waxing crescent moon pass near Venus and then Mars on May 23 and 24. Venus reaches it maximum northern declination of 26 degrees this month and its highest point above the ecliptic.

Saturn rises at 3:30 a.m. at the beginning of May and two hours earlier by the end of this month. The ringed planet has moved into Aquarius now after spending the last couple of years in Capricorn. Since it takes 29 years to orbit the sun, it spends just over two years in each zodiac constellation.

Jupiter rises about an hour later in Aries the Ram. Both Jupiter and Saturn are also in direct or prograde motion now. Jupiter ended its last retrograde on Valentine’s Day. Jupiter only takes 12 years to orbit once, so it spends one year in each of the 12 zodiac constellations. The King of the Planets also undergoes its retrograde loop for four months out of each year. If you have access to a telescope (many libraries have 4.5-inch reflecting telescopes that you can check out like a book) you can see Jupiter being occulted or covered up by a thin waning crescent moon at 7:45 a.m. on the morning of May 17. Both the moon and Jupiter will rise around 4:30 and continue to get closer.

Mercury is slowly moving into our morning sky this month, but it won’t be visible until the last week of May. On May 23, it will be just 7 degrees due east of the much brighter Jupiter in the eastern morning sky about an hour before sunrise. Our first planet will reach its greatest western elongation from the sun at 25 degrees on May 29.

The last highlight for this month will be the Eta Aquarid meteor shower which peaks on Saturday morning the 6th. It is caused by that most famous of all comets, Halley’s. This comet also causes our October 21 Orionids as we pass through the tail of this comet twice each year.

You can normally expect up to 50 meteors per hour from a dark sky site, but the full moon occurs the day before, so it will wash out over 90% of the meteors, leaving only the most brilliant ones to be visible. It will still be worth trying to catch some of them if it is clear. They last for several weeks, so you could also look for them before and after their peak. This comet dust is about the size of a grain of sand and even less dense. So just as the comet itself can become very impressive and easily visible by sprouting a huge coma around it the size of Earth (the nucleus of the comet is less than 10 miles in diameter), and a tail stretching up to 100 million miles through space, these tiny individual pieces of this famous comet are also very impressive as they crash into our atmosphere right at the limit of space, which is about 60 miles high. That is about the distance from Portland to Augusta, but straight up.

These brilliant streaks of light are created by their great speed of 40 miles per second as they get ionized as they start encountering some more air molecules at that height, similar to the 5,000 degree temperatures that a space capsule like Orion endured upon reentry.

MAY HIGHLIGHTS

May 5: Full moon is at 1:34 p.m. … In 1961 Alan Shepard made the first suborbital flight on the Mercury Freedom 7 spacecraft. Yuri Gagarin completed one orbit of Earth just before that on April 12, 1961.

May 6: The Eta Aquarid Meteor Shower peaks.

May 10: Cecilia Payne-Gaposchkin was born in 1900. She was one of the famous group of women astronomers called the Harvard Computers that developed the spectral classification system for stars along with many other amazing discoveries.

May 11: The fifth and final servicing mission to the Hubble Space Telescope took place in 2009. The last shuttle, STS-135, would be launched just two years later on July 8, 2011.

May 12: The Adler Planetarium in Chicago became the first planetarium in the Western hemisphere in 1930.

May 13: The moon passes near Saturn this morning.

May 14: In 1973 our first orbiting space station, Skylab was launched into orbit. It only lasted until July 11, 1979 and it was only occupied by three crews for a total of 171 days.

May 15: Williamina Fleming was born in 1857. She was another important member of the Harvard Computers.

May 17: The moon passes near Jupiter this morning. Jupiter will be occulted by the moon at 7:45, 2 1/2 hours after sunrise. The moon also passes just north of Mercury this morning.

May 19: New moon is at 11:53 a.m.

May 27: First quarter moon is at 11:22 a.m.

May 28: Frank Drake was born in 1930.

May 30: Mars is at aphelion, or farthest from the sun, at 155 million miles.

Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.