August is one of the best months of the year for amateur skywatchers to get out at night and look at the universe.
The Milky Way, under dark skies, will be at its best in August. Get binoculars and gaze south after the sky is dark. Patrol the enormous number of stars in our galaxy. Even in good binoculars, you will not be able to resolve the great majority of stars visible. There are so many stars, and they are so far away, they make a sort of "star haze." However, this star haze will give you an idea of what a very large number of stars there are in the Milky Way. The Milky Way is an average spiral galaxy, but it contains more than 100 billion stars--maybe very many more!
In the first few days of August, the waxing crescent Moon will be about five degrees to the right of Mars -- about 5 thumb-widths. This should help in locating Mars. You will probably be under-excited at seeing Mars through a telescope -- it is rather small.
The first-quarter Moon, what many people call a half moon, will lie between Mars and Saturn at dusk, so look on either side of the Moon to find these planets.
In August, you will also see the largest full Moon of the year (the night of Aug 10th). The full Moon will rise around sunset and set around sunrise in the U.S. and it should be quite bright if the weather cooperates. The full Moon is not much to look at with magnification because the brightness reduces the contrast of surface detail to a very great degree. However, if you see this full Moon, you can say you saw the biggest one of the year.
The annual Perseid meteor shower will occur the night of Aug. 12-13. It will be best after midnight. However, considering the Moon phase, the bright Moon will make observing the meteors difficult. Even so, one might expect to see 25 to 50 meteors from a dark site. Stand where you can put the Moon behind you and look in the direction in the sky opposite it. This may help a bit in seeing some of the brighter meteors.
Around dawn on Aug. 18, Venus and Jupiter will be just 0.2 degrees apart in the sky. In actuality, they are not close at all, but from our perspective from our orbital position in the Solar System, they will appear quite close. If you have never found these two planets in the night sky before, now would be the best time to locate them, even if you have to get up a bit early. If you wait until Aug. 23 to look for Jupiter and Venus, the waxing crescent Moon will form a nice triangle with these two planets.
If you make some of the observations noted above, you may wonder why the planets and the Moon move in such a way as to appear to come close to one another in the night sky. The reason for this is that the Moon, the Sun, and the planets all pass through the sky in roughly the same path. Our Solar System, seen edge on, would be flat. As we Earthlings look out toward Saturn and inward toward the Sun, the planets and the Sun and Moon will move just about along the same line in the sky. This imaginary line is called the Plane of the Ecliptic. All of the eclipses of both the Sun and the Moon will also always occur along this line. This is the way gravity works in our Solar System. In their separate orbits around the Sun, the planets "line up" along the equator of the Sun, where the gravitational attraction between the Sun and the planets is strongest. This may be a bit difficult to imagine, but these gravitational mechanics have been at work for very many years and the process is quite reliable.
In August, get the bug repellent, grab the binoculars, and go out and see the wondrous night sky!
-- Dr. David Cater is a former faculty member of JBU. Email him at [email protected]. The opinions expressed are those of the author.
Editorial on 07/29/2014