This Week’s Sky at a Glance, 2021 July 3 – 10 ~by Curt Nason
With the Milky Way becoming prominent on summer evenings, binocular stargazing is a great way to pass the time. From Cygnus heading south the Milky Way is split by the Great Rift, a region where the starlight between us and the centre of our galaxy is blocked by vast dust clouds. The western side of the Milky Way runs through parts of Lyra and Ophiuchus to Scorpius, and the eastern side runs through Aquila and Scutum to Sagittarius.
A good place to start observing is with orange Antares in Scorpius. Check out the colour of this supergiant star, and pick out the globular cluster M4 in the same field of view to its right. East of Scorpius is the Teapot asterism that makes up much of Sagittarius the Archer. If you extend the two stars at the top of the Teapot’s spout to the right you will find M6, the aptly named Butterfly Cluster. To its lower left is a large star cluster called M7 or Ptolemy’s Cluster. To the right of M7 is a pair of bright stars, Shaula and Lesath, which marks the stinger of Scorpius. They have been nicknamed the Cat’s Eyes.
About a binocular-field width above the Teapot’s spout you will find a fuzzy patch with a small cluster of stars in or near it. The fuzzy patch is a cloud of dust and gas called M8, the Lagoon Nebula, where stars are forming. Radiation from hot young stars makes the gas glow, and it can be seen with the naked eye in rural areas. A telescope will reveal dark dust lanes in the nebula that suggest its lagoon name. The cluster of stars is called NGC 6530, where NGC stands for New General Catalogue. Just above M8 is a smaller cloud, M20 or the Trifid Nebula, and the nearby star cluster M21.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:33 am and sunset will occur at 9:13 pm, giving 15 hours, 40 minutes of daylight (5:41 am and 9:15 pm in Saint John). Next Saturday the Sun will rise at 5:38 am and set at 9:10 pm, giving 15 hours, 32 minutes of daylight (5:46 am and 9:12 pm in Saint John). At 7:27 pm on Monday the Earth will be at aphelion, its greatest distance from the Sun for the year.
The slim waning crescent Moon passes to the left of Mercury Thursday morning, and it is new the following evening. Mercury is at its greatest elongation from the Sun and Monday and it brightens over the week. Venus can be seen shortly after sunset low in the northwest, sitting on the western edge of the Beehive star cluster this Saturday. Mars pops into view later five degrees to the upper left of Venus. Saturn rises before 11 pm in the upper middle of Capricornus, followed by Jupiter 50 minutes later in western Aquarius.
Questions? Contact Curt Nason.