While you were outside watching for Perseid meteors last week, did you notice the sky full of planets?

Mars, Jupiter and Saturn have been with us all summer, but now Venus is entering the scene as well. Even little Mercury makes a curtain call in this late summer planet fest.

Mars and Saturn are front and center, just as darkness falls this week. Look due south starting around 9 p.m., and you’ll spot not two, but three, bright objects clustered together in a cute little triangle. Mars is the brightest one, and the westernmost of the trio. Saturn is the second brightest, at the top of the triangle.

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The third bright object isn’t a planet at all, but a distant red supergiant star named Antares. Its stellar nature is readily apparent because it is the only one of the three objects that twinkles. Watch Antares flicker and flash with every color of the rainbow, due to Earth’s atmosphere breaking up the star’s light like a prism would.

Mars is rapidly receding from us and fading, after its spectacular close encounter with Earth in May. Watch from night to night as Mars makes a beeline eastward, pinching up the little triangle until it disappears completely on the nights of Aug. 23 and 24.

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That’s when Mars passes between Saturn, above, and Antares, below, forming a straight line. Mars will appear less than 2 degrees from Antares and about 3 degrees from Saturn. After Aug. 24, the triangle reforms, but this time Mars will be the eastern-most of the trio.

This week offers the perfect opportunity to compare the ruddy color of Mars to that of its namesake star, Antares. Because of this star’s fiery red hue, the ancient Greek’s called it Antares, meaning, “the rival of Mars.” With Mars and Antares side by side, you tell me, which one looks redder?

Meanwhile, very low in the western sky about 30 to 45 minutes after sunset, you can catch sight of the planet Venus, just emerging from its pass behind the sun. Look for it in the golden sunset glow before any other stars (or planets) pop into view.

With each passing sunset, Venus will be a little bit higher and a little bit easier to see. You will need a clear, unobstructed view to the western horizon, though, to catch it this week.

A little higher up in the sunset glow, and not quite as bright as Venus, you can spot the planet Jupiter, roughly a fist width to the upper left of Venus. Jupiter is sinking lower into the sunset each night while Venus is climbing higher.

Watch the gap between the sky’s two brightest planets shrink up this week as they converge for a cosmic collision on the evening of Aug. 27. At least, it will look like a collision. The two planets will seem to merge into a single bright beacon, but Jupiter actually will be four times farther away from us than Venus.

The space you will see between the two planets, if you look very closely, will be about the width of a string of spaghetti held at arm’s length. I’ve never seen two bright planets pass this close in the sky — that’s how rare this is.

Start looking for the planets around 8:15 p.m. on the night of Aug. 27, again, very low in the western sky. Use binoculars to enhance the view.

Finally, you might be able to catch a glimpse of the planet Mercury this week, too, shining faintly about 4 degrees below Jupiter. It is faint, though, and the sunset glow will make it all the harder to see. If you do spot it, pat yourself on the back because you will become an honorary member of the “Five Planets in One Night Club.”

Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Steamboat Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper. Check out Jimmy’s astrophotography website at Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College's Steamboat Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper. Check out Jimmy’s astrophotography website at http://www.jwestlake.com.Professor Jimmy Westlake teaches astronomy and physics at Colorado Mountain College’s Steamboat Campus. His “Celestial News” column appears weekly in the Steamboat Today newspaper. Check out Jimmy’s astrophotography website at http://www.jwestlake.com.