Jasper Dark Sky Festival

This Week’s Sky: August 21 – 28

A total eclipse of the Sun and a lovely evening conjunction.

Brecher-M57-July-25-2012

The Ring Nebula (M57) in the constellation Lyra is a prime summer-sky sight. Courtesy Ron Brecher

All Week

The view facing east, one hour before sunrise.

Going… going… but not yet gone. That’s what you might say to yourself as you step outdoors and see Jupiter hanging low in the southwest at dusk. Big Jove reached opposition back in April and has been a constant evening companion ever since. The planet currently shines at magnitude –1.8 and will continue to linger ever lower until its November conjunction with the Sun. Faring slightly better is magnitude 0.4 Saturn, now well past the meridian as darkness falls. With its magnificent rings, Saturn is always worth training a scope on—but the earlier the better. One hour after sunset, it sits less than 24 degrees above the horizon, as seen from Toronto, Ontario. The farther north you are, the lower it appears. To see the night sky’s final planet, you have to wait until the predawn, when Venus rises a little before 4 a.m., local daylight time. Gleaming at magnitude –3.9, Venus easily outclasses the bright winter stars it shares the dawn sky with.

August 21

As this map illustrates, the closer to the path of totality you’re situated, the greater the percentage of the solar disc eclipsed by the Moon. Map Courtesy Michael Zeiler/GreatAmericanEclipse.com

The Moon is new today at 2:30 p.m., EDT. And, as you may have heard, it also passes in front of the Sun, producing at total solar eclipse visible along a narrow path that spans the breadth of the contiguous United States. All of Canada will get to enjoy a far less dramatic (but more convenient) partial eclipse. For much, much more on this exciting event, visit our eclipse page and review the July/August issue of SkyNews.

August 25

The view facing west-southwest, 45 minutes after sunset.

Look to the west-southwest early this evening to see a tidy, equilateral triangle featuring a waxing crescent Moon, Jupiter and Spica. The Moon and Jupiter sit roughly five degrees apart, approximately five degrees above first-magnitude Spica. The trio are a lovely naked eye sight and, with a sufficiently attractive horizon, should make for a fine photograph.

Weekend Stargazer

Lyra

The constellation Lyra is home to the Ring Nebula, M57. Click on the chart for a full-size version.

On the August 25 – 27 weekend the Moon sets early enough for you to enjoy some deep-sky observing in the late evening. One object currently in prime position is the Ring Nebula (M57), in Lyra. It’s a well-known deep-sky wonder, yet can be difficult for beginners to track down.

The problem is usually one of perception. The Ring glows at magnitude 8.8, so it’s relatively bright. But what newbies often fail to take into account is the nebula’s small size. It spans only 70 arc seconds—a little less than twice the apparent size of Jupiter. Fortunately, M57’s location is easy to find. The object is situated between the stars Lambda (λ) and Beta (β) Lyris—a little closer to Beta than Lambda. Even small telescopes used at low magnification will show the tiny ghostly disc, but you’ll need higher power to see the dark central hole that gives the Ring its name.

If you have a big scope and are up for a serious challenge, you might try for the nebula’s notoriously difficult 15th magnitude central star. The key is to apply plenty of magnification on a night with steady seeing. But even under these conditions, the star can elude even experienced observers. Don’t be surprised (or disappointed) if you can’t spot this feeble spark.

At SkyNews we love to read about your experiences and see your photos. You can share them with us by e-mailing skynews@skynews.ca.

Categories: This Week's Sky
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