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Star Trak: August 2019

For immediate release: July 29, 2019

BLOOMINGTON, Ind. -- The annual Perseid meteor shower will peak on the night of Aug. 12-13. The Perseid shower is one of the most popular every year because it happens on warm summer nights, when gazing at the starry sky is always enjoyable. This year its peak will be just two days before full moon, so moonlight will interfere with the display. In a dark sky as many as 110 meteors per hour may be visible. Some will leave smoke trails that last several seconds after the meteor has vanished.

The Perseids will be visible for most of August, though there will be fewer meteors to see the farther from the peak date you watch. If the peak is hidden by clouds, try looking for meteors again as soon as the night sky is clear. To minimize the effect of local light pollution, which can obscure as many as half of the meteors, try to avoid artificial lights.

Perseids Meteor ShowerPerseids Meteor Shower
Photo Credit: NASA/JPL

Face east if you have a clear view in that direction, and use a building or tree to block the moon. Look about halfway up the sky from the horizon. You won't need binoculars or a telescope because the meteors move much too fast for those devices. The Perseids produce more of the extremely bright meteors called fireballs than any other shower. The chances of seeing a fireball will be greatest near dawn.

The Perseids may appear anywhere in the sky, but they will seem to originate from a point called the radiant in the constellation Perseus, which gives these "shooting stars" their name. The higher the radiant is above the northeastern horizon, the more meteors will be visible. Perseus is just north of the W-shaped constellation Cassiopeia in the Milky Way. Meteors near the radiant will have short trails because we see them nearly straight on, while those far from the radiant will look longer because they are seen from the side.

Most meteor showers happen when Earth crosses the orbit of a comet, and the Perseids come from Comet Swift-Tuttle. The meteors are caused by particles released from the comet's nucleus and left behind in space. As Earth plows through this stream of debris, ranging in size from sand grains to pebbles, each particle slams into our atmosphere at a speed of more than 30 miles per second and burns up almost instantly from friction with air molecules. The resulting heat momentarily creates a streak of glowing air that we see as a meteor. All of this happens about 60 miles above the ground, regardless of how close some meteors may appear.


Mercury will have its best morning appearance of the year during August for observers at mid-northern latitudes. On Aug. 9 it will rise about 90 minutes before the sun and be 10 degrees above the east-northeastern horizon a half hour before sunrise. Nearby the two bright stars Castor and Pollux will form a line with the planet. Mercury will continue to brighten as the month passes, but it will drop lower until it is lost in the sun's glow by Aug. 26.

Jupiter will be near the bright red-orange star Antares in the constellation Scorpius during August. The giant planet will be highest in the south around nightfall, so that will be the best time to view it with a telescope. As soon as evening twilight ends, astro-photographers at dark sites will have fine opportunities to capture Jupiter against the background of the Milky Way. Jupiter will set around 2 a.m. local time at the start of the month and two hours earlier by month's end.

Thirty degrees east of Jupiter will be bright yellow Saturn. At the beginning of the month the ringed planet will be highest in the southern sky around 11:30 p.m., sinking out of sight in the west by 4 a.m. All of that will happen two hours earlier at month's end. Saturn's famous rings will be tilted 25 degrees to our line of sight.

Venus and Mars will be hidden from view by the glare of the sun throughout August.

Light pollution

If you look at the constellation Cassiopeia in the northeast on a clear summer night and can't see the Milky Way sprawling high across the sky from the northern to the southern horizon, it means your sky has significant light pollution. This is the case for about two-thirds of the world's population. This dimming of the night sky is caused by excessive artificial lighting, much of which is wasted. See the International Dark-Sky Association website for more information.

Moon phases

The moon will be at first quarter on Aug. 7, full on Aug. 15, at third quarter on Aug. 23 and new on Aug. 30.

Author: Hal Kibbey Email: hkibbey [at]

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