~ St. Maarten’s Backyard Astronomy for July 14 - 16 ~
Sun rises at 5:44am
Sun sets at 6:51pm
Lunar phase: 4th quarter, waning crescent
Moon rises at 12:04am
Moon sets at 12:48pm
This weekend, let’s look at a lesser-known constellation. Why? Because, dear star gazer, the moon will be late to rise, and slim when it does – in other words, no bright moonshine to wash out the dimmer celestial lights. It’s the perfect time to find new stories among the stars.
The first thing you are likely to notice after sunset is Venus – as far as size and density, it’s the planet most like our own. Venus is a boldly brilliant star-like point of light and at this time of the year, you’ll find it in the western sky for a couple of hours after the sky becomes dark.
Use Venus as a starting point to find Mars. Another Earth-like planet, Mars is much dimmer than Venus and has a slightly red tinge to its light. Look above Venus and slightly to the left. While the planet Mars is a bit smaller than Earth, it is similar in density. These three planets are in what is known as the Goldilocks Zone – not too hot and not too cold. Close enough to the sun to stay warm, but not as close as Mercury, which could never be habitable to life as we know it. Beyond the orbit of Mars, space becomes very cold indeed. This weekend, Venus and Mars are close to the constellation of Leo the Lion – and Regulus, the brightest star in Leo, sits between the two planets.
Last weekend, I suggested looking southward to see a parade of constellations crossing through the night, but we want to look farther east this weekend, and a little higher up, to a constellation known as Scutum, the Shield.
If you get far away from any land-based lights, you might see our Milky Way galaxy. It’s a wide and hazy band of distant stars and gas that stretches up from the Southwest at the horizon towards the Southeast near our zenith point (i.e., overhead). The aborigines of Australia call it the Backbone of the Night, and I love that imagery. If you recall last weekend’s discussion about Sagittarius and Scorpius, the Milky Way passes between them. Look a bit farther up and to the left and there you’ll find a small but noteworthy constellation called Scutum.
There are only five stars in Scutum’s outline, but the constellation is noticeable in a dark sky because the Milky Way around it is so rich. In fact, Scutum lies near the Milky Way’s centre. Scutum doesn’t mark the exact centre of our galaxy, but it’s pretty close!
Scutum is one of two constellations named after real people (the other is Coma Berenices, named for an Egyptian queen) and it has an interesting history. In 1683, the Polish astronomer Johannes Hevelius named it for his king, Jan Sobieski III, who led his army to victory in the Battle of Vienna. Hevelius thought the five stars resembled the coat of arms on the king’s shield, so the constellation became known as Scutum Sobiescianum, or the Shield of Sobieski.
The Shield isn’t big, and it requires a dark sky to be seen, but you’ll see it nicely this weekend, with the unaided eye or binoculars. The very noticeable Teapot of Sagittarius is below Scutum – and the bright star Vega in the constellation Lyra shines high above.
Next weekend, we look for the Delta Aquariid Meteor Shower – the first of several meteor showers that will occur in late summer and fall!