We are halfway through summer now and this month promises two close planetary conjunctions, an asteroid occultation for part of the country, the closest and biggest full moon of the year in the middle of three super moons this summer, and the annual Perseid meteor shower. So get outside as often as you can and look up to be inspired by the wonders of our ever-changing solar system. The nights are slowly getting longer to give you more time to enjoy and understand these majestic motions always going on around us.

Mars has slowly been closing the gap on Saturn throughout the summer. As this month starts, they are 13 degrees apart. A fist held up at arm’s length covers 10 degrees of the sky. Notice that the star Spica is about the same distance to the right of Mars as Saturn is to the left, in a nearly straight line.

The waxing crescent moon will drift by all three celestial objects during the first four days of the month. It is moving eastward at the rate of half a degree per hour. Notice that Mars starts out a little brighter than Saturn, but as it catches up with the ringed planet at the rate of half a degree per day, it also gets a little fainter. By the time the red planet catches up on the 23rd, it is the same brightness as Saturn, which is 0.6 magnitude. Both planets are back in their prograde (eastward) motion since they are well past opposition.

The other nice planetary conjunction unfolding this month is between Venus and Jupiter, our two brightest planets. They will be less than a half degree apart, which is the width of the full moon, 45 minutes before sunrise on the 18th. Notice that Venus is two magnitudes, or about six times brighter than Jupiter. After that the king of the planets will rise higher in the sky even as Venus sinks a little lower. Watch them again during the mornings of the 21st through the 23rd as the slender waning crescent moon approaches the pair of planets as it sinks lower through the winter hexagon.

On the evening of the 19th, a faint asteroid named 232 Russia will occult a faint star in Libra for 2 to 3 seconds. It will only be visible over a narrow path from North Dakota across Pennsylvania and into southern New Jersey. These can be very interesting and educational events if you can set up some cameras along the edges of the track and get a very detailed image of the exact shape of the asteroid as it briefly covers up the star.

The closest full moon of the year will happen at 2:09 p.m. on the 10th. It will be within 25 minutes of perigee at that time. That makes it the closest of the three consecutive super moons that we will have this summer. The July and September ones occur within one day of its perigee, which qualifies it to be called a super moon. That only happens once about every 13 months on average, but this summer we get to see three in a row.

A super moon is up to 30 percent brighter and 14 percent larger than a full moon at apogee, when it is farthest from Earth. The moon is about 222,000 miles away at perigee and 252,000 miles away at apogee. Even that much of a difference could be hard to distinguish and the moon would never go from being very close to perigee one month to being very close to apogee the next month. The full moon always looks much larger when it is first rising over the horizon because of an optical effect called the moon illusion.

Another good way to look at it is to picture the moon about 28 earth diameters away at perigee during the super moons and about 31 earth diameters away at apogee, when the full moon appears at its smallest, also called a micro moon. That may still seem far away, but it is only 1.2 seconds at the speed of light.

The next total lunar eclipse will occur Oct. 8. It will be visible for us on the East Coast when the full moon sets, which will be toward sunrise. That will be the second in a series of four total lunar eclipses in a row with no partial ones in between, which is called a tetrad. That is extremely rare and has only happened seven times in the last 2,000 years.

The Perseid meteor shower will peak on Tuesday night the 12th into Wednesday morning. Unfortunately that will happen just two days past the full moon. That means the waning gibbous moon will rise about two hours after sunset, washing out the best part of the shower, which usually occurs after midnight toward the morning as the earth is spinning into the meteor shower instead of away from it.

However, you can salvage some of this year’s shower by being aware that any meteors that emanate from its radiant while that point is still low on our horizon will become earth grazers, and leave a long and spectacular trail through our atmosphere. There may only be one or two of these before the moon rises, but they will become unforgettable, burning their way into your memory even as they burn their way through our atmosphere.

Instead of a split second for a normal meteor close to the radiant, an earth grazer could last up to 15 seconds and even change color several times as it plunges deeper into our atmosphere. On Aug. 10, 1973, a brilliant earth grazer was even visible in the daytime as it skipped off our atmosphere over Jackson Lake in the Grand Tetons in Wyoming.

You can start looking for early Perseids as soon as the month begins and well before the full moon. Next year, the peak of the Perseids will be ideal, with no moon to interfere with any part of one of nature’s great shows.

Caused by Comet Swift-Tuttle, which orbits the sun every 133 years, the Perseids usually produce about 60 to 100 meteors per hour if the sky is clear and not washed out by the moonlight. Smashing into our atmosphere at around 40 miles per second, most of these sand grain-sized pieces of comet dust burn up around 70 miles high in less than one second. Look toward the Northeastern sky for Perseus, which will rise around 9 p.m. on the 12th. Try to catch some spectacular earth grazers before that time.


Aug. 2: The moon will be visible between Spica and Mars one hour after sunset.

Aug. 3: First quarter moon is at 8:50 p.m. The moon will pass between Mars and Saturn, and will occult Saturn over Australia. In 2004, the Messenger Spacecraft was launched to Mercury and has since revealed several of its secrets.

Aug. 4: The Phoenix Mars lander was launched in 2007.

Aug. 6: In 2012, the Mars science lab rover, Curiosity, safely landed. It has made many exciting discoveries and has taken some great pictures.

Aug. 10: In 1990, Magellan entered orbit around Venus. Full moon is at 2:09 p.m. This is called the Sturgeon or Green Corn Moon. This super moon will be the largest full moon of the year, happening just 25 minutes before its perigee.

Aug. 12: In 1877, Asaph Hall discovered Deimos, the smaller of the two moons of Mars, which are probably captured asteroids. If you could walk around on Phobos or Deimos, the two moons of Mars, you would only weigh a few ounces and you could jump out of a 1,000-foot deep crater and throw a baseball into orbit. The Perseid meteor shower peaks tonight.

Aug. 17: Last quarter moon is at 8:26 a.m.

Aug. 18: Venus and Jupiter will be less than a half degree apart low in the eastern morning sky, 45 minutes before sunrise. This is their closest approach in 14 years. Try to get come pictures of the pair of planets.

Aug. 22: In 1963, the X-15 jet set a world record of 354,000 feet, or 67 miles high, which is about where most of the meteors burn up in our atmosphere.

Aug. 25: New moon is at 10:13 a.m.

Aug. 31: Saturn and Mars will be close to the moon one hour after sunset.

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

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