The month of August is named for Augustus Caesar. The first day of this month marks the halfway point of our summer. The days are now continuing to get shorter even as the nights are getting longer again, which is great for seeing and enjoying more of the wonders of the night sky.

There will be several very interesting events this month. Mars will catch up with Saturn and line up with Antares for a nice show, and then Venus will catch up with Jupiter for a much closer conjunction on the 27th. The famous Perseid meteor shower will peak on the 11th and 12th, and it should be a much better show than usual thanks to Jupiter. The Juno mission is already getting great pictures of Jupiter, and there is only one year to go to the next great total solar eclipse and the first one to completely cross our country in about 100 years.

The month starts with three planets lined up in a straight line, 27 degrees long in the evening sky just after sunset. We haven’t had any bright planets low in the western evening sky for a while, so this will be a nice change and you don’t even have to get up early. Jupiter is the highest one, then Mercury is next, and then Venus is just over the horizon 20 minutes after sunset. You may need binoculars to see Venus that low. Also notice that it is right next to Regulus, the brightest star in Leo and the 21st-brightest star in the whole sky.

Then keep watching this trio as the slender waxing crescent moon slides right under Mercury on Thursday evening the 4th and then passes directly under Jupiter the next evening. By the middle of the month, Mercury will get within 4 degrees of Jupiter. Venus will keep catching up with Jupiter all month long and will be less than half a degree apart on Saturday the 27th. That will be the closest conjunction of any planets this year. They will be even closer in the southern part of South America, as these two brightest planets will blend together when viewed without binoculars.

When watching Jupiter carefully this month as those other planets appear to get close to it, remember that we just achieved a remarkable feat of engineering by getting Juno safely to exactly where it had to go to begin its highly dangerous elliptical orbits around this energetic planet in October. Going way beyond threading a tiny cosmic needle, scientists got even closer to the exact spot at the exact time than the New Horizons mission to Pluto, which is eight times farther away at about four billion miles. The Juno cam already took some great pictures, including the first real-time movie of the four large Galilean moons orbiting this giant planet like a miniature solar system.

Try to appreciate the great size and power of the king of our planets. At 10 Earth diameters across, Jupiter is 318 times heavier than Earth and spins around in only 10 hours. If you could see its intense magnetosphere, Jupiter would cover one full degree of the sky, which is twice the width of the moon or sun in our sky. That’s 120 times bigger than the visible part of this planet. Jupiter may look totally calm and serene at this great distance, but nothing could be further from the truth. To quote Scott Bolton, the chief scientist on the Juno mission, “its gravity is like a giant slingshot, slinging rocks, dust, electrons, whole comets. Anything that gets close to it becomes its weapon.”

Juno is definitely a suicide mission, but first it should discover many unknown answers about Jupiter, including if it even has a solid core, and much more about the nature of its powerful magnetosphere. It could even solve the greatest mystery of all in the solar system, exactly how Jupiter and the other planets formed, and in turn how exoplanets formed in other solar systems.

The billion-dollar Juno probe has nine highly sophisticated scientific instruments that will give us raw data to interpret. Its electronic brain is shielded by titanium so that it won’t get destroyed too quickly. Juno should be able to complete about 35 orbits over the next two years before we purposely crash it into the planet to avoid contaminating any of its moons that may harbor some life forms.

A little farther east along the ecliptic, you will encounter some equally unique but less violent planets, Mars and Saturn. By the 23rd, Mars will have caught up with Saturn and will form a straight line with the orange giant star named Antares in Scorpius. Golden Saturn will be the highest one, then orange Mars, and then Antares, which is about three times fainter than Mars, even though it really is one of the largest stars in our whole galaxy at 700 times the size of our sun.

The most famous of all the meteor showers, the Perseids, peak every August. Caused by Comet Swift-Tuttle, you can usually expect about 60 meteors per hour. This year we may get double that or even more, due to a recently discovered influence of Jupiter’s strong gravity on part of this comet’s debris field. Swift-Tuttle last returned in 1992, but there were also much better counts than usual every 12 years before and after that date. It takes Jupiter nearly 12 years to orbit the sun, which coincides perfectly. The last one was in 2004 and we are due for the next one this year. The moon will be waxing gibbous, but it will set around 1 a.m. That is the best time to watch a meteor shower anyway, because then we are on the side of the earth that is turning directly into the meteors, similar to looking out your front car window when driving into a snowstorm instead of looking out your back window. So get out and enjoy this amazing display of nature’s silent fireworks and try to take some photographs to preserve this exciting event.


Aug. 2: New moon is at 4:44 p.m.

Aug. 3: The Messenger spacecraft was launched to Mercury in 2004.

Aug. 4: The Phoenix mission was launched to Mars in 2007.

Aug. 5: The moon will be directly below Jupiter tonight.

Aug. 6: The Curiosity Rover was launched to Mars in 2012.

Aug. 10: First quarter moon is at 2:21 p.m.

Aug. 11: The Perseid meteor shower peaks tonight into the 12th. You could expect twice as many meteors as usual, up to 150 per hour.

Aug. 12: Asaph Hall discovered Deimos in 1877. He would discover Phobos, the larger moon of Mars at 14 miles across, just six days later.

Aug. 17: In 2006, Voyager 1 reached 100 a.u. into the solar system, or over twice the distance to Pluto. It reached the heliopause at about 123 a.u. in 2013.

Aug. 18: Full moon is at 5:26 p.m. This is also known as the grain, green corn or sturgeon moon.

Aug. 23: Mars forms a vertical line with Saturn and Antares tonight.

Aug. 25: In 2003, the Spitzer infrared space telescope was launched.

Aug. 27: Venus and Jupiter have an extremely close conjunction of less than a half degree.

Bernie Reim of Wells is co-director of the Astronomical Society of Northern New England.

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