Over the next few weeks, stargazers are going to have a chance for some great sights as summer skies creep closer and closer. From now through June, eagle-eyed astronomers will be able to pick out Mars and Jupiter as they sparkle in the night sky, while the star pattern known as the “summer triangle” makes its first appearance of the year.
On the heels of Mercury’s transit across the sun last week comes the opposition of Mars this weekend. Though it sounds like the title for a cheesy sci-fi flick, the exciting event only happens once every two years and 50 days when the red planet swings its closest to Earth.
Because Mars orbits farther from the sun than Earth does, one year on its surface is about equal to two Earth years. That means that every two years, the Earth swings between the sun and Mars, causing the two celestial objects to appear opposite to each other in the night sky—hence the name, “opposition of Mars,” Deborah Byrd writes for EarthSky.org.
Mars is usually pretty easy to pick out year-round, but this is a special time for stargazers. On the evening of Saturday, May 21, Mars will be at its opposition, but it will continue getting brighter every night until it reaches its closest point to the Earth on Monday, May 30, Alan MacRobert reports for Sky & Telescope.
But don't wait to check out Mars’ opposition—the longer you wait, the harder it may be to see it. As the red planet enters full opposition, it will enter the constellation Scorpius, which may make it harder to pick out. A few days later, Mars will cross over into the nearby Libra constellation before ducking back into Scorpius as the Earth once again orbits away from its planetary neighbor, Michael Bakich writes for Astronomy Magazine.
It should make for a pretty picture on Saturday evening, as Mars will form a rough rectangle with the full moon to its left, the star Antares beneath it, and Saturn diagonally across from the red planet.
As Mars enters opposition, stargazers have another treat to seek out: the Summer Triangle. This star pattern has too few stars to technically be considered a constellation, but for fans of warm weather, sighting it should be a good sign. The Summer Triangle is composed of just three stars (Vega, Deneb, and Altair) and usually heralds the start of summer by beginning to rise in the sky between mid-May and early June, Richard Talcott writes for Astronomy Magazine. By now, the Summer Triangle typically clears the horizon by 11 P.M. local time. To pick it out, locate its brightest star, Vega, in the constellation Lyra. Deneb will be to its lower left, and Altair will be to the lower right of both stars, completing the trio.
While it always helps to have a telescope or binoculars handy, the brightness of both Mars and the Summer Triangle should make them easy to spot, if the night is clear. If you have been waiting for warmer weather to start looking up at the sky, these might be the right objects to start the summer season off right with.