The Sky This Week: May 6 – May 8

The Sky This Week: May 6 – May 8

Mars heads toward peak visibility, a young Moon shines faintly, and the Eta Aquariid meteor shower peaks.

 

Friday, May 6
New Moon occurs at 3:30 p.m. EDT. At its New phase, the Moon crosses the sky with the Sun and so remains hidden by our star. Because the Moon reaches perigee, the closest point in its orbit around Earth, only 15 hours earlier (at 12:13 a.m. EDT), residents in coastal areas can expect higher than normal tides for the next few days. At perigee, the center of the Moon lies 222,344 miles (357,827 kilometers) from Earth’s center.

Mars passes 1.2° north of the 7th-magnitude globular star cluster M80 tonight. The view through binoculars or a telescope at low power should be impressive.

Jupiter sports a pair of “black eyes” tonight as the shadows of two of its large moons cross the jovian cloud tops. The shadow of outermost Callisto treks across the planet’s north polar region from 11:18 p.m. until 1:42 a.m. EDT. Innermost Io’s shadow crosses the gas giant from 12:39 a.m. to 2:53 a.m. EDT. It’s easy to tell the two shadows apart because Io’s will appear much closer to Jupiter’s equator.

Saturday, May 7
With an age of 4.5 billion years, “young” might not seem an appropriate word to describe our Moon. But tonight, you have an exceptional opportunity to see what astronomers call a “young Moon” — a slender crescent visible low in the west some 30 to 45 minutes after sunset. With New Moon having occurred yesterday afternoon, only 2 percent of our satellite’s disk appears illuminated this evening. You should notice an ashen light faintly illuminating the Moon’s dark side. This is “earthshine,” sunlight reflected by Earth that reaches the Moon and then reflects back to our waiting eyes. Use binoculars for the best view. The young Moon will be much easier to see tomorrow evening, when it appears significantly higher and some 7 percent illuminated.

Sunday, May 8
Although the calendar says May, the sky’s Summer Triangle returns to prominence this month. The asterism’s three bright stars — Vega in Lyra, Deneb in Cygnus, and Altair in Aquila — all clear the horizon by midnight local daylight time. An hour later, they rule the eastern sky. Vega shines brightest and appears at the apex of the triangular asterism. Look for Deneb to Vega’s lower left and Altair to the lower right of the other two. The Summer Triangle will grace the Northern Hemisphere’s evening sky from now through the end of the year.

 

Source

Astronomy Magazine