Fred Barrett | Jul 04, 2018
You can’t beat July and August for the beauty and quantity of constellations that can be observed in the night sky. The nicest ones and the easiest to find are imbedded in the Milky Way. It is a white band of stars and dark dust clouds that arches high overhead from the southern to the northern horizon. Let’s go on a tour. I will describe what can be seen at roughly 9p.m. EST in the middle of July. Starting at the southern horizon, you will see the “Teapot”, an asterism in the constellation Sagittarius. An asterism is a formation of stars in a constellation that can resemble an everyday object. In this case, a Teapot, and at the end of the spout you can find the centre of our galaxy. Moving up the through the Milky Way, we soon find Aquila, the “Eagle.” At the top of this constellation is the bright star Altair. Further north, at the zenith of the sky, straight up, we can observe Cygnus, the Swan. It has the shape of a cross, and at its northern end at the top of the cross is the swan’s tail and the beautiful star Deneb. Looking southwest of Cygnus is the constellation Lyra. Its nickname is the “weaver” since its shape resembles a tool used to spin yarn. The star Vega at its top is hard to miss. It shines very brightly. The 3 stars, Altair, Deneb and Vega are known as the Summer Triangle. They offer a handy reference point for finding other constellations in the summer sky. Just west of Lyra is Hercules. A great ball of stars, called a globular cluster, is easy to find through your binoculars at the north west quadrant of the constellation. Astronomers call it M31. Next stop on the path, as we slip down towards the northern horizon, is the constellation Cepheus. We soon come upon Cassiopeia. It appears in the form of a great ‘W’ shape. Just north of Cassiopeia, near the horizon and between it and Perseus, is a wonderful double-cluster of stars that are quite easy to find in binoculars. Find yourself a star map and travel the trail along the Milky Way. There’s so much to see and discover. Moving from interstellar space and back to Earth, have a look at the Moon. In binoculars or a small telescope, a great deal of detail pops out – craters, mountains, valleys and plains. The worst time to observe the Moon is when it is full. The Sun’s light falls from straight overhead and the details that are brought out by shadows are completely washed out. The best time to observe is when the Moon is at its waxing or waning quarter. It is the best time for shadows. Take a look at the terminator boundary between the light and dark sides – there’s plenty of mountain and crater shadows to bring out detail. Here’s another tidbit; the Earth is farthest from the Sun at midsummer.
Mars is spectacular all month and it’s up all night. It will be closer than it’s been in 15 years. Don’t miss it! As night falls, Mercury and Venus are in the west. Look southeast for Mars and Jupiter and shift to the south for Jupiter. By midnight, Mars is still in the southeast and Jupiter has moved to the southwest. Saturn is in the south.
July 6: Last quarter Moon. Earth is at aphelion, its farthest distance from the Sun – 94.5 million miles.
July 12: New Moon.
July 13: Moon is at perigee, closest to the Earth – 355,355kms.
July 15: At midnight, there is a nice view of the moon passing 1.6 degrees north of Venus.
July 19: First quarter Moon.
July 20: The Moon is 4 degrees north of Jupiter at 8p.m. EDT.
July 25: The Moon is 2 degrees north of Saturn.
July 27: The Moon is at apogee – 403,864 Kms. Mars is at opposition – it sits in a direct line between the Sun and Earth. At 6p.m. EDT, the Moon is 7 degrees north of Mars. Full Moon. This month it is called the Full Hay Moon – haying time. It is also called Full Thunder Moon since most thunderstorms seem to occur in this month.
July 30: The modest Delta Aquariid meteor shower peaks.
July 31: Mars is closest to the Earth: 35.8 million miles. Note that opposition is not the closest distance between Earth and Mars.
Keep looking up!
“The Beginner’s Observing Guide by Leo Enright is an invaluable companion for adventures in the sky. It also contains useful star charts. It can be ordered from the Royal Astronomical Society of Canada at www.rasc.ca/publications. A subscription to our very own excellent Canadian astronomy magazine “SkyNews” can be arranged at the RASC website as well.