May is a great month for stargazing with a host of celestial events happening in the morning and evening skies.
On May 17, a slim crescent moon will rise about an hour before the Sun. From much of the United States and Canada, you’ll be able to see Jupiter appearing very close to the Moon. In some southern U.S. states, Jupiter will pass behind the Moon as the pair rises in morning twilight. From western states, Jupiter will be behind the Moon, in occultation, as the duo rise. Jupiter will start to emerge from behind the Moon as the Sun comes up. To observe this event, you’ll need a clear view of the horizon, and a pair of binoculars will be essential as many locations in the U.S. will be in daylight during this occultation.
Following sunset from May 22 through 24, you’ll be able to witness a close grouping of the Moon, Venus, and Mars in the western sky. The Moon will sit between the two planets on the 23rd. Venus has been rising higher in the sky each evening for the past few months, but in May, it’ll reach its highest point in the western sky.
For those stargazing from the Southern Hemisphere, there are some key differences in the night sky compared to the Northern Hemisphere. For instance, there’s no counterpart to the North Star in the Southern Hemisphere, and the seasonal star patterns that a northern observer are familiar with appear flipped upside down when viewed in southern skies.
Two entire galaxies, the large and small Magellanic Clouds, can be easily observed in the southern sky with the unaided eye. These are dwarf galaxies that orbit our own Milky Way galaxy.
The eta Aquariid meteor shower is active throughout April and May, peaking in the pre-dawn hours of May 5. This year could be particularly impressive as an outburst year with 120-160 meteors per hour expected.
“A meteor shower is like a normal rain shower, with 50-60 meteors per hour,” said Bill Cooke, lead of NASA’s Meteoroid Environments Office at the agency’s Marshall Space Flight Center in Huntsville, Alabama. “An outburst is like a thunderstorm, with greater than normal meteor activity expected. A meteor storm is like a tornado, where meteor rates are over one thousand per hour.”
Despite the full moon lighting up the sky and washing out the faint meteors, this year’s eta Aquariid meteor shower is not one to miss. In terms of producing fireballs, NASA camera data places it #6 among meteor showers. These bright fireballs are caused by Earth running into a dense stream of debris from Comet Halley, a lot of which was ejected more than 3,000 years ago. Moving at 148,000 mph, some of these fireballs leave glowing “trains” in their wake that last for several seconds to minutes.
How to View
The eta Aquariid meteor shower is viewable in both the Northern and Southern hemispheres, with higher rates of visibility to observers in the Southern Hemisphere. This is due to the radiant’s location in the constellation of Aquarius. Meteors will be observable after midnight, but the peak times are 3-4 a.m. until dawn.
Regardless of your geographic location, you’ll want to find an area well away from city lights for best viewing. Give yourself about 30 minutes in the dark for your eyes to adapt – this means not looking at your phone. Look AWAY from the moon and take in as much sky as possible.
The next major meteor showers will be the Perseids in August, and the sister show to the eta Aquariids, the Orionids in October.
But there’s plenty more skygazing to do this month. Check out What’s Up in May from NASA Jet Propulsion Laboratory.