Our Celestial Coast: A Triangle of Planets

Reprinted from the Island Free Press

The triangle formed by Mars, Saturn and Antares will continue to parade across the southern sky this month. It was visible near the southeast horizon at “nautical” dusk yesterday. Mars is the bright red lead star and Saturn is the trailing star. Antares, which is also red, is not as bright as the two planets and can be found between them, but a little closer to the southern horizon.

Saturn will be at opposition on Friday. That means it will be the brightest it gets. This is your best chance to get a look at the ringed planet and its moons. Saturn will be visible all night and, as usual, can be viewed with binoculars. Sometimes, you can make out the biggest moon, Titan, through binoculars, but it’s difficult.

Mercury will be at its highest point above the eastern horizon on Sunday morning. This makes it a great time to get up early and view the planet. Mercury will rise at 4:38 a.m. and probably stay visible until about 5:30 a.m.

Jupiter will start June a little to the south of the zenith. It will be visible until it sets in the west at about 1:50 a.m. It will follow this same pattern throughout the month, appearing a little bit more to the west at dusk and setting about two minutes earlier each night.

The summer solstice will be on June 20. That means the days will start getting shorter, but, on the plus side, the nights will get longer and give us more time to look at the stars.

May Highlights

May did not offer a lot of clear nights, so I tried to make the most of the few that came along. Surprisingly, the southern skies offered the best views because of the prevailing winds.

Moon Phases

New moon: Saturday
First Quarter: June 12
Full moon: June 20
Last Quarter: June 27

Astronomy Talk

Civil dusk is when the center of the sun is six degrees below the horizon in the evening. There are a few stars and planets visible at this point, but the sky in the background is still bright through a telescope.

Nautical dusk is when the center of the sun goes 12 degrees below the horizon in the evening. There is still a bit of sky glow from the sun, but it’s usually dark enough to start doing some observing particularly in the eastern side of the sky.

Astronomical dusk is when the center of the sun is at 18 degrees below the horizon. That’s the time when the sun doesn’t add any sky glow.

Currently, civil dusk is about 40 minutes before nautical dusk. Astronomical dusk follows about 40 minutes later. In the winter, there is about 30 minutes between civil dusk and nautical dusk. Similarly, there is about 30 minutes between nautical dusk and astronomical dusk at that time of year.

A planet is said to be in opposition when it is on the opposite site of the Earth from the sun.

Active galaxies are galaxies that have a small core of emission embedded in an otherwise typical galaxy. Models of active galaxies concentrate on the possibility of a supermassive black hole, which lies at the center of the galaxy.

This story is provided courtesy of the Island Free Press, a digital newspaper covering Hatteras and Ocracoke islands. Coastal Review Online is partnering with the Free Press to provide readers with more environmental and lifestyle stories of interest along our coast. You can read other stories about Hatteras and Ocracoke here.

About the Author

Gerry Lebing

Gerry Lebing is a retired computer scientist with the U.S. Geological Survey. Astronomy is a subject that Gerry says he has always been interested in and one that he pursues seriously -- he's built an small observatory next to his house in Waves on Hatteras Island. You can send him questions about the night sky by email, gerry@wmi.org.