| Jul 05, 2012


By Fred Barrett

What a great Venus transit! I hope you all saw the excellent article by Julie Druker on the front page of the June 7th Frontenac News. Check the Frontenac News website archives if you missed it.

July and August are the glory days for observing. The Milky Way arches high overhead from the southern to the northern horizon. Starting In the south is the “Teapot”, an affectionate name for Sagittarius. It looks just like a teapot! Moving up through the Milky Way, we quickly come to Aquila, the Eagle, with its bright star Altair. Moving on we come to the Swan, Cygnus, at the zenith of the sky and its bright star Deneb. To the west of Cygnus is Lyra, also called the weaver, since its shape resembles a yarn spinner. The star Vega at its top is hard to miss.

The three stars Altair, Deneb and Vega are known as the summer triangle. They offer a handy way to orient yourself in the summer night sky if you want to venture farther afield.

To the west of Lyra is Hercules with its great globular cluster of stars called Messier 13. Next is Cepheus as we slide down towards the northern horizon. Soon after is Cassiopeia near the horizon. If you have your binoculars out, there is a beautiful double cluster of stars that you should be able to make out just north of Cassiopeia, a beautiful sight.

Don’t forget the Moon. You can see a lot of detail without having to resort to optical aids. Of course with binoculars or a modest telescope more detail pops out: craters, mountains, valleys, plains.

When is the best time to observe the Moon? If you think it's around full moon you are wrong! In fact this is the worst time. Sunlight is falling on the moon's surface from straight overhead when it is full, and it looks like a white plate with little detail. The best time to observe the Moon is when it is at one of its two quarters. The sunlight is coming in at an angle from the left or right at this time. A few days either side of the quarter Moon is just as good. Pay special attention to the terminator, the boundary between light and dark. Shadows from surface features are at their maximum. If you watch long enough, you can actually see the shadows change in size.

Full Moon for July occurs July 3. It is variously called the Summer Moon, Hay Moon, Ripe Corn Moon and Full Buck Moon. Bucks start to grow new antlers at this time. Different First Nation societies have other names depending on where they live or lived and the climate their area. The Moon name often has to do with the growing season or the weather. The next full Moon occurs on August first and it is called the Grain Moon and Sturgeon Moon. Sturgeon was more easily caught at this time.

Summer weather has nothing to do with how far we are from the Sun. As a matter of fact, the Earth is farthest away from the Sun in the summer. The Earth is at aphelion or its greatest distance from the Sun on July 4. That distance is 94.5 million miles or about 153 million kilometers.

There is a sight that you should really try to see in early July. From about July 1st to the 10th and about an hour before sunrise, look low to the east northeast. The Pleiades, Jupiter, Venus and the star Aldebaran form a near straight line. Aldebaran in the middle of the Hyades cluster and the red baleful eye of the constellation Taurus the Bull, is at the bottom. Venus is slightly above and very near Aldebaran. Next above is Jupiter and above it the Pleiades. They get higher as the days go by. Watch them as the days pass and they slowly change their formation. In mid-July the crescent moon passes through the formation. I know that dawn occurs hideously early at this time of year but it is well worth getting up an hour before the Sun rises at least for one morning to see this spectacular sight!

Look west southwest about an hour after sunset from about July 3rd on and you will see Saturn and Mars in the constellation Virgo near the bright star Spica. If you follow an arc from the handle of the big dipper you arrive at Arcturus and if you continue in that arc an equal distance you arrive at Spica. Both stars are bright. They get closer as the month progresses. Mars actually passes between Saturn and Spica in mid-August!

There are no meteor showers this month but I’m giving you a heads up for the marvelous Perseid meteor shower on August 11th. It will be a moonless night. Conditions couldn’t be better.

 

If you have questions or suggestions, Fred Barrett may be contacted at This email address is being protected from spambots. You need JavaScript enabled to view it.

The Beginner’s Observer’s Guide by Leo Enright is available at the Sharbot Lake Pharmacy or by contacting the Royal Astronomical Society of Canada www.rasc.ca/publications, subscriptions for our very own excellent Canadian astronomy magazine, Sky News, are also available from RASC..

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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