This month offers a compromise of the best of the best. In July, Jupiter and then six days later, Saturn, came to opposition. In August, Venus arrived at its greatest western elongation from the sun in the predawn morning sky. October will be the "month of Mars" as the Red Planet comes nearest to Earth for the next 15 years. So, overall, during September we'll have four bright planets appearing very close to their best. Jupiter and Saturn are conveniently placed in the evening sky.

Mars makes its appearance before midnight and finally Venus arrives on the scene between midnight and dawn. The only planet "out of the loop" is Mercury, which will be miserably placed all month long, very low near the west-southwest horizon after sundown and buried deep in bright twilight.

In our schedule, remember that when measuring the angular separation between two celestial objects, your clenched fist held at arm's length measures roughly 10-degrees. Here, we present a schedule below which provides some of the best planet viewing times as well directing you as to where to look to see them.

Mercury

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Mercury — is going to have a rotten evening apparition for skywatchers at north temperate latitudes this month. This in spite of the fact that it increases its angular distance east from the sun from 14 degrees to 26 degrees by Oct. 1, the time of greatest elongation. However, the zero-magnitude planet also moves well south of the sun, and from latitude 40 degrees north is unfavorably situated, setting only 45 minutes after sunset.

Nevertheless, you can try to spot it on a clear evening by scanning with binoculars 20 to 30 minutes after sundown. Look near the horizon due west early in September, and west-southwest late in the month. On Sept. 22, Mercury passes 0.7 degrees to the upper left of 1st-magnitude Spica, brightest star in Virgo. Mercury is more than twice as bright as Spica, but is quite difficult to see because of its very low altitude and being deeply immersed in bright twilight.

Viewers in the Southern Hemisphere (Montevideo, Johannesburg, Melbourne), on the other hand, have a grand view of Mercury in September; it gets fairly high in the west in twilight, affording a fine view of its conjunction with Spica.

Venus

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Venus — dominates the night sky from the time it rises, about 3.5 hours before the sun all month. It shines at magnitude -4.2 and is positioned about one-third of the way up in the eastern sky by the middle of morning twilight. Despite the fact that Venus was at greatest elongation (maximum angular separation) from the sun on Aug. 17, the planet is even a bit higher in September — about 40 degrees high at each September sunrise around latitude 40 degrees north.

On the morning of Sept. 6, Venus is in line with the Gemini Twins, Castor and Pollux (though a distant 10.5 degrees from Pollux). On the 13th, Venus glides about 2.5 degrees south of M44, the pretty Beehive Star Cluster in Cancer, and on the following morning, a lovely celestial tableau adorns the eastern sky as a crescent moon, three days before new, sits 4.5 degrees to the left of brilliant Venus. Finally, Venus ends the month just 3.5 degrees to the upper right of bluish 1st magnitude Regulus in Leo — which it will meet in a very close conjunction on Oct. 3.

Mars

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Mars — approaching opposition, is making a grand entry every evening in the eastern sky. It comes up a little over two hours after sunset on the 1st and 50 minutes after sundown (during mid-twilight) by month's end. Give it at least two hours to climb above the poor seeing near the horizon. By then it will be at an altitude of just over 20 degrees (as seen from 40 degrees north latitude).

Mars appears much sharper and steadier when it transits the meridian, at around 4 a.m. local daylight time on Sept. 1, 3 a.m. at midmonth, and 2 a.m. on the 30th. Its altitude is then nearly 60 degrees. The distance from the Earth decreases from 45.6 to 38.8 million miles (73.4 million to 62.4 million km) this month, while the Red Planet brightens dramatically from magnitude -1.8 to -2.5. In fact, on Sept. 28, it will supplant Jupiter as the second brightest planet. Mars is that brilliant yellow-orange "star" sitting just above the waning gibbous moon late on the evening of Sept. 5.

Jupiter

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Jupiter — glaring at magnitude -2.4, is highest in the south at evening twilight fades. It reversed its retrograde (westward movement relative to the stars) on Sept. 12, after halting above the handle of the Teapot of Sagittarius. On Sept. 24, you'll find it about 4.5 degrees to the upper left of the moon.

Saturn

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Saturn — glows in the south after dusk, about 7.5 degrees east (left) of Jupiter. A steady yellowish light in the otherwise rather empty constellation of Capricornus. On Sept. 25, it is positioned about 3.5 degrees above the waxing gibbous moon. Saturn is very conveniently placed for early evening viewing now that it is well past its July 20 opposition.

In addition, since the Earth has sidled off the line from the sun to Saturn, we no longer look squarely into Saturn's sunlit face. This means we see a little around the planet's eastern edge to view some of its shadow falling on the rings. A small telescope shows the rim of a black shadow quite clearly.

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Joe Rao serves as an instructor and guest lecturer at New York's Hayden Planetarium. He writes about astronomy for Natural History magazine, the Farmers' Almanac and other publications in New York's lower Hudson Valley. Follow us on Twitter @Spacedotcom and on Facebook.