What’s Up in the Sky – July, 2017
Observe Three Planets This Month
July can be a great month for sky watching in spite of certain drawbacks. First and foremost is the fact that the Sun sets after 9:00 p.m. all month, which means it doesn’t get dark enough for viewing until after ten. Other hinderances include insects and humidity, but quite often the month provides at least a few favorable nights.
One way to get around the lack of darkness is to do lunar observing. A first quarter Moon is visible well before sunset and can be viewed for several hours afterwards. July begins with the Moon at this phase so there will be viewing opportunities for the first week of the month. Just google “observing the Moon” for tips on when, where, and how to view the various mountains, valleys and craters.
Another opportunity occurs during the last week of July following the New Moon on the 23rd. In fact, on Monday, July 24, the very thin crescent Moon is joined by the planet Mercury which is just below the star Regulus. This will be a challenging but rewarding observation. You will need binoculars or a small telescope and a clear, unobstructed view of the western horizon (Lake Michigan is a perfect spot). Sunset that night is at 9:13 p.m. so begin your search about twenty to thirty minutes later. Look slightly north of due west for the thin crescent of the Moon, then scan left (south) to spot Mercury and Regulus. They will be the brightest objects in the area so if you see anything, that would be them.
You may want to follow this up with another try the following night when the Moon will be more toward the south and to the left of the other two objects. You will also notice that Mercury will have gone from the lower right to the lower left of Regulus. They will be separated by about the width of two fingers held at arm’s length.
Two other planets are well placed for observing in July: Jupiter and Saturn. When darkness falls, look in the southwest for Jupiter and southeast for Saturn. They should be easy to spot as they will be two of the brightest objects in that part of the sky. Also, Jupiter will be just below the First Quarter Moon on June 30 and very close to the Crescent Moon on July 28. Saturn will be right below the Gibbous Moon on July 6.
The best viewing, however, will be the following week when the Moon is out of the way and the sky is dark. A good telescope will give excellent views of Saturn’s rings and Jupiter’s moons. A desktop planetarium such as Stellarium (http://www.stellarium.org/) can be used to predict dates and times of events such as transits and occultations of Jupiter’s moons. Those are times when one or more of the moons either passes in front of the planet or disappears behind it. Both are very interesting events you can observe up in the sky.
This month in history:
July 3: Harrison Schmitt born – 1935
July 4: Mars Pathfinder lands on Mars – 1997
July 6: Newton’s book, Principia, is published – 1687
July 9: Voyager 2 flies past Jupiter – 1979
July 20: First humans walk on Moon (Apollo 11) – 1969
July 24: First rocket launched from Cape Canaveral – 1950
