Flowers will blossom and young, tender leaves will reappear on the trees as spring finally reaches New England this month. Just as the earth will be transforming, the sky above also promises some dramatic action.

The most spectacular planetary conjunction in several years will unfold in our dawn sky throughout the month.

This exquisite celestial dance began 20 minutes before sunrise today in the eastern sky. As if some of the actors were a little shy, three of the four participating planets will only be visible with binoculars.

Mars and Jupiter will be less than half a degree apart early in the month. Mercury will be a little farther up and to the right of the pair. Brilliant Venus, just to the right and above Mercury, is the only one that will stand out until the other planets become bolder later in the month.

Watch carefully as this solar system play of neighboring planets unfolds all month. The two brightest actors, Venus and Jupiter, will be only half a degree apart, which is the width of the full moon, on the morning of May 11. Jupiter and Mars will climb higher even as Venus and Mercury will sink lower.

Mars will only become bold enough to be seen without binoculars during the last week of the month.

Saturn will be the lone actor on the celestial evening stage. Only a month past opposition, when the ringed planet was at its best and brightest, Saturn still will be a stunning sight through a telescope.

As if half of our newly reduced solar system of eight planets dancing around all month were not enough, we also will be treated to tiny pieces of the most famous of all comets, Halley’s, tearing into our upper atmosphere.

The Eta Aquarid meteor shower will peak before dawn on Friday under moonless skies, and you can expect about 20 to 25 meteors per hour away from any light pollution.

The Oct. 21 Orionids are also caused by the earth passing through the debris trail of Halley’s Comet. It’s the only comet debris trail that our orbit around the sun carries us through twice each year.

Since all of the Eta Aquarid meteors will appear to emanate from the constellation of Aquarius, which is fairly low in the sky, this is not one of the best showers for observers in the Northern Hemisphere.

Our friends in the Southern Hemisphere get a much better view of this celestial fireworks spectacle, as they can expect up to 70 meteors per hour.

The sand grain-sized pieces of comet dust that will streak through our atmosphere about 70 miles up at 40 miles per second will be very swift and bright, and half of them could leave persistent trains that will slowly twist and unravel in glitter and smoke.

There also will be a nice little comet named Garradd that should reach about 10th magnitude this month. You will need at least a small telescope to see it, but it should reach 6th magnitude, or just about naked-eye visibility by autumn. By coincidence, this comet also is hanging out in Aquarius.

Comet Garradd is heading north, so it will rise earlier and climb higher into the predawn sky by late in the month. This comet is a first-time visitor from the Oort Cloud, where all the comets originate. It is harder to predict these, but some original visitors can get really bright like Comet Hale-Bopp did in March 1997.

If Comet Garradd continues to brighten as expected, it could become visible to the naked eye by early 2012.


May 1: On this day in 1949, Gerard Kuiper discovered Nereid, the second largest moon of Neptune after Triton. The Kuiper belt, which contains billions of objects, including some the size of Pluto, was named after him.

May 3: New moon is at 2:51 a.m. EDT.

May 4: The slender waxing crescent moon can be seen between the Pleiades and Hyades star clusters in Taurus this evening 45 minutes after sunset. It will be 12 degrees farther eastward along its path above these two star clusters the next evening at the same time.

May 5: On this day in 1961, Alan Shepard became the first American in space. The Russian Yuri Gagarin was the first human in space, just 3 weeks earlier on April 12, 1961.

May 6: The Eta Aquarid meteor shower peaks this morning.

May 10: First quarter moon is at 4:33 p.m.

May 11: Venus passes just half a degree south of Jupiter this morning. The two brightest planets in our sky won’t be this close to each other again until August 2014.

May 14: Our first orbiting space station, Skylab, was launched on this day in 1973.

May 15: On this day in 1958, the Russians launched Sputnik 3. Also on this day in 1963, the U.S. launched Faith 7, the last Mercury program flight. Today the moon is at perigee, at 225,020 miles, its closest point to Earth.

May 17: Full moon occurs at 7:09 a.m. This is also known as the Flower, Budding, Milk or Planter’s Moon.

May 20: On this day in 1978 we launched Pioneer-Venus 1.

May 22: On this day in 1969, the Apollo 10 lunar module descended to within 50,000 feet of the lunar surface.

May 24: Last quarter moon is at 2:52 p.m.

May 25: On this day in 1961 President John F. Kennedy challenged the nation to a moon landing before 1970. We made it on July 20, 1969, with just over 5 months to spare.

May 27: The moon is at apogee, or farthest from the earth, at 251,657 miles.

May 28: On this day in 1959, the first primates in space, Rhesus monkeys named Able and Baker, completed a suborbital flight.

May 29: On this day in 1919, Einstein’s General Theory of Relativity passed its first major test. During a total solar eclipse over Africa and South America, astronomers photographed and proved that the light from a star behind the eclipsed sun was curved by the gravitational field of the sun by exactly the amount that his theory predicted.

May 30: The waning crescent moon passes close to four nicely aligned planets 30 minutes before sunrise low in the eastern sky. The planets are, in order from top to bottom, Jupiter, Mars, Venus and Mercury.


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