This Week’s Sky: July 15 – 22

The (nearly) full Moon and Saturn meet after midnight.

The International Space Station.

The International Space Station. (Courtesy NASA)

All Week

The view facing south at midnight.

The view facing south at midnight.

A trio of bright planets currently adorns the sky, though for most observers that trio amounts to a duo. Planet #3, Venus, is no longer an easy catch. Although the morning “star” gleams a brilliant magnitude –3.9, it rises in bright twilight a mere 40 minutes before the Sun, making the planet tricky to see unless you have an unobstructed east-northeast horizon. Most of the solar-system action now takes place in the late evening, when you’ll find two excellent telescopic worlds: Jupiter and Saturn. Jupiter is in prime position, reaching the meridian at roughly 10:30 p.m., local daylight time. That’s when it’s highest and due south. At magnitude –2.5, Jupiter is by far the brightest object in the night sky (excluding the Moon) and a snap to identify. Trailing behind Jupiter, 30 degrees to the east, is Saturn. The magnitude 0.1 ringed wonder is only one week past opposition and culminates a little before 1 a.m., so you’ll have to stay up late to view it at its best. Unfortunately, even at that time, Saturn remains quite low. For those in the southernmost part of the country Saturn achieves an altitude of just 24 degrees.

July 15/16

The Moon and Saturn as seen in a small telescope at 28×.

The Moon and Saturn as seen in a small telescope at 28×.

Tonight the Moon has a close encounter with Saturn. This will be an enjoyable sight in steadily held binoculars, or a small telescope used at low power. The Moon is closest to Saturn at 4:37 a.m., EDT, when they’ll be separated by just 41 arc minutes. Unfortunately, for those in the eastern half of the country, the pair will be setting around that time. However, for observers on the West Coast, the objects will be well positioned when closest.

July 16

The Moon is full today at 5:38 p.m., EDT.

July 20

Fifty years ago today, humans first set foot on the Moon. For more on this historic event, check out the July/August issue of SkyNews.

Weekend Stargazer

This rendering of the International Space Station was created using the Heavens Above ISS Interactive 3D Visualization tool.

This rendering of the International Space Station was created using the Heavens Above ISS Interactive 3D Visualization tool.

Sky watchers will have to contend with light from the waning gibbous Moon and short nights over the July 19 – 21 weekend. That largely rules out hunting down faint deep-sky objects. Instead, you might want to set your sights on objects closer to home—a lot closer to home. The one upside to the season’s long, lingering twilight is that artificial satellites are easier to spot. For the same reason you can catch the glint from jetliners high overhead after sunset, you can also watch satellites slowly drifting across the sky during deep twilight—at the altitude of these objects, the Sun is still shining brightly.

The best known human-made object currently in orbit is the International Space Station (ISS). It circles our planet every 90 minutes at an altitude of 400 kilometres. If you’ve ever wondered about the identity of “that bright light” moving west to east, there’s a good chance it’s the ISS. As it happens, this is a good weekend for sighting the space station both at dusk and dawn.

If you want to catch the ISS, timing is everything. Fortunately, there are a number of excellent on-line resources that make figuring out when and where to look a piece of cake. My favourite is the Heavens Above site, which lists ISS passes and provides detailed viewing information. One of the site’s coolest features is its ISS Interactive 3D Visualization—a sort of real-time, ISS-eye view of the Earth. Try it out—it’s lots of fun. But more importantly, go outside to watch the ISS silently glide across the sky.

At SkyNews we love to read about your experiences and see your photos. You can share them with us by e-mailing [email protected].

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