This Week’s Sky at a Glance, June 10 – June 17 ~by Curt Nason
Summer is globular cluster season. Globulars are massive, spherical clusters of old stars that orbit the core of a galaxy. They are typically composed of hundreds of thousands of stars in a volume of space where, in our galactic neighbourhood, there might be a few hundred stars. Picture a snow globe after you shake it, and imagine the tiny flakes as stars. Globular clusters formed about the same time their host galaxies were forming, approximately 12 billion years ago. The area of sky around Sagittarius, Scorpius and Ophiuchus above them is where we find many of the brighter globulars in the Messier catalogue.
The brightest star in Scorpius is the red supergiant Antares, which marks the heart of the scorpion. Easily within a binocular field to the right of Antares is the globular cluster M4, one of the closest to us at 7000 light years. Viewing from a rural location makes a big difference in how well you will see this and other globular clusters. Further to the right of Antares a bow of three bight stars forms the scorpion’s claws, and halfway between Antares and the upper star of the bow is M80, looking much tinier than M4 because it is nearly five times more distant. To the upper left of the Sagittarius Teapot’s lid is M22, another globular gem, and just above the lid is the tougher target of M28.
Although these objects are a hazy patch of light in binoculars, they are spectacular in a telescope at high magnification under a dark sky, when several of the individual stars can be seen. A common description is that of sugar crystals on black velvet.
This Week in the Solar System
Saturday’s sunrise in Moncton is at 5:27 am and sunset will occur at 9:09 pm, giving 15 hours, 42 minutes of daylight (5:36 am and 9:11 pm in Saint John). Next Saturday the Sun will rise at 5:27 am and set at 9:12 pm, giving 15 hours, 45 minutes of daylight (5:35 am and 9:14 pm in Saint John).
The Moon is full and a day past apogee on Friday, June 9, making this the smallest full Moon of the year, the annual Puny Moon. It is also called the Strawberry Moon, Honey Moon, or the Trees Fully Leaved Moon. The Moon is at third quarter on June 17. Jupiter will look a little different in a scope or binoculars for an hour after midnight on the evening of June 10, with only one of its four large moons visible. One moon is behind the planet and two are passing in front of it. Saturn is at opposition on Thursday, rising at sunset and being visible all night. Its rings are at their best viewing for the next 15 years, and around opposition they are also brighter due to the sunlight reflecting directly back toward us. Venus dominates the very early morning sky and it is near its greatest extent from the Sun. Around 10 am, try finding it high in the sky with binoculars, and if you are successful try to see it without binoculars.
The William Brydone Jack Astronomy Club meets at the UNB Fredericton Forestry / Earth Sciences Building on June 13 at 7 pm. All are welcome.
Questions? Contact Curt Nason.