How often do we have a Blue Moon in July? For the answer, you have to look to a concept from astronomy and calendar studies, at what’s called the Metonic cycle.
Blue Moon coming! As seen in the photo above by Patrick Casaert, the moon has been waxing to full this week. Patrick used a blue filter to create his moon photo, and if you see the moon in tonight’s sky, you’ll see it’s nearly full … but not at all blue in color. Yet, as the second full moon for the month of July, many will call it a Blue Moon.
Orion the Hunter appears each Northern Hemisphere winter as a mighty constellation arcing across the south during the evening hours. But, before dawn in late July and early August, you can spot Orion in the east. Thus Orion has been called “the ghost of the shimmering summer dawn.” The Hunter rises on his side, with his three Belt stars – Mintaka, Alnitak and Alnilam – pointing straight up.
The Great Square of Pegasus can point you to the constellation Aquarius and to the radiant point of the Delta Aquarid meteor shower.
In a dark, moonless night sky in late July and early August, you can see up to 15 to 20 Delta Aquarid meteors per hour. In 2015, the moon is in the way. Get ready, though. The Delta Aquarids will still be flying at the peak of this year’s Perseid meteor shower, which will be mostly moon-free!
What’s a Double Double star? Ordinary binoculars show you Epsilon Lyrae as two stars in one. But look more closely. A telescope reveals that each of the two stars in the Epsilon Lyrae system is, in itself, a double star. That’s why Epsilon Lyrae is famous for being the Double Double star, a single point of light to the eye that’s really four stars in one. One stellar pair circles around the other stellar pair in an intricate gravitational dance.
The moon is to the north of the constellation Scorpius the Scorpion tonight. You can pick out two stars near the moon – in the Tail of the Scorpion – are called Shaula and Lesath. Together, these two represent the Scorpion’s Stinger. Shaula is some 350 light-years away and Lesath is about 500 light-years away
The moon was full on July 2, and it’ll be full again on July 31. The second of two full moons in a calendar month is often called a Blue Moon.
Tonight – July 26, 2015 – the southernmost constellation of the Zodiac – Scorpius the Scorpion – lurks low in the evening sky. You can locate the Scorpion because the moon is moving through this part of the sky. You’ll find star Antares, the brightest star in the constellation Scorpius the Scorpion, and the planet Saturn, near the July 26 waxing gibbous moon.
Late July 2015 presents the extended peak of the Delta Aquarid meteor shower – though under the glaring night of the almost-full moon. The best viewing hours are after midnight and before dawn, centered around 2 a.m. (3 a.m. daylight-saving time) for all time zones around the world. This long and rambling shower is officially active from about July 12 to August 23 each year, so you may be better off to wait for a couple weeks – or when the moonlight is much less obtrusive. This shower overlaps with the more famous Perseid meteor shower in August. Those who observe the Perseids are likely to see some Delta Aquarid meteors in the mix. Follow the links inside to learn more.