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Perseid meteors: All you need to know

Perseid meteor shower peak was predicted for the morning of August 12. If you missed it, watch for meteors in a country sky between midnight and dawn Saturday morning.

Early Perseid meteor caught on the morning of July 25, 2016 by Ken Christison.  Start watching for these meteors!  Thank you, Ken.

View larger. | Early Perseid meteor caught on the morning of July 25, 2016 by Ken Christison. Notice how colorful it is. Thanks, Ken.

UPDATE AUGUST 12, 2016: METEOR OUTBURST REPORT! The Sociedad de Astronomía del Caribe (Astronomical Society of the Caribbean) reports a possible Perseid outburst seen from La Pitahaya, Cabo Rojo, Puerto Rico this morning.

We saw 506 Perseid meteors in a period of 4.75 hours. But we did see an outburst from 3:40 am to 4:00 am local time. During that short period, we counted 7.5 (7 to 8) meteors per minute, which means we saw 150 meteors in just 20 minutes!

One of the Perseids seen was unforgettable, says EarthSky contributor Eddie Irizarry of the Sociedad de Astronomía del Caribe:

… after the fast meteor streaked the skies, it left a bright, light blue colored smoke trail that lasted about 45 seconds as seen with the naked eye! The dissipating trail was observed for an additional 60 seconds using binoculars. That was a big one!

In 2016, astronomers expected an outburst of Perseid meteors on the night of August 11-12. The shower is still going on. You can see meteors in the Perseid shower, from anywhere on Earth, in the moon-free hours before dawn on Saturday morning, August 13. From southerly latitudes in the Southern Hemisphere, you’ll enjoy the shower, too, but you’ll see fewer meteors than we see from the Northern Hemisphere. The waxing gibbous moon will set before the predawn hours on August 12 and 13. Follow the links below to learn more:

Why a Perseid meteor outburst in 2016?

When and how should I watch the Perseid meteor shower in 2016?

General rules for Perseid-watching.

What’s the source of the Perseid meteor shower?

What is the radiant point for the Perseid meteor shower?

See it! Photos of 2016’s Perseid meteor shower

Predicted Zenithal Hourly Rate (ZHR) for Perseids in 2016. The ZHR is the rate of the shower at its peak, when the radiant point is overhead (before dawn from all parts of Earth).  Chart via a presentation by meteor expert Bill Cooke, head of NASA's Meteoroid Environment Office, from presentation he gave at the Meteoroids 2016 conference in the Netherlands in June, 2016.

Predicted zenithal hourly rate (ZHR) for Perseids in 2016. The ZHR describes the shower at its peak, when the radiant is overhead (before dawn from all parts of Earth). Chart via meteor expert Bill Cooke, head of NASA’s Meteoroid Environment Office.

Why a Perseid meteor outburst in 2016? EarthSky asked Bill Cooke, head of NASA’s Meteoroid Environment Office, why we should expect a Perseid meteor outburst in 2016. He told us:

Every time Swift-Tuttle goes around the sun, it deposits a trail of particles which we call a meteor stream. Over time, the gravitational influence of Jupiter and other giant planets (but mainly Jupiter) changes the particle orbits, and as a result, their close approach distances to Earth will vary.

If the change for a given stream is towards Earth’s orbit, we may see greater than normal activity when our planet passes the trail’s nodal crossing.

This year Jupiter’s influence has moved the 1079, 1479, and 1862 [meteor] streams closer to Earth, so all forecasters are projecting a Perseid outburst with double double normal rates on the night of August 11-12 [evening of August 11, morning of August 12].

The peak rates were expected to last about half a day. And predictions varied for the actual time of the peak rates.

Predicted times - via computer models - for peak of Perseid meteor outburst in 2016. Translate UTC to your time zone, here. Chart via a presentation by meteor expert Bill Cooke, head of NASA's Meteoroid Environment Office, from presentation he gave at the Meteoroids 2016 conference in the Netherlands in June, 2016.

Predicted times – via computer models – for peak of Perseid meteor outburst in 2016. Translate UTC to your time zone. Chart via meteor expert Bill Cooke.

As evening falls on August 10, 11 and 12, the waxing gibbous moon will be shining near planets Mars and Saturn, and the star Antares. The green line depicts the ecliptic - the sun's yearly path and the moon's monthly path in front of the constellations of the Zodiac. The moon will set before the predawn hours on August 11, 12 and 13,  at which time the Perseid meteors  streak the nighttime most abundantly.

As evening falls on August 10, 11 and 12, the waxing gibbous moon shines near planets Mars and Saturn, and the star Antares. Read more about the moon’s passage near these planets.

When and how should I watch the Perseid meteor shower in 2016? The peak night was probably last night, August 11-12. Typically Perseid peaks are about 100 meteors per hour. This year, with an outburst expected, the rates may have been about double that for some observers on Earth.

The Perseid meteor shower is known to rise to a peak gradually, over several weeks, and then fall off rapidly in the days following the shower. Will you see meteors on Saturday morning, August 13? Yes, probably, if you go someplace where the sky is dark (free of city lights) and if you wait to watch until after moonset.

Also remember, the the Delta Aquarid meteor shower is still rambling along steadily. You’ll see the Perseids and Delta Aquarids together.

No matter how many meteors you see, you might see something, and it might be a lot of fun.

In a typical year, although the meteor numbers increase after midnight, the Perseid meteors still start to fly at mid-to-late evening from northerly latitudes. South of the equator, the Perseids start to streak the sky around midnight.

Here’s how to watch in bright moonlight. Sit within a moon shadow, and otherwise enjoy an open view of sky.

Don’t rule out early evenings, either. As a general rule, the Perseid meteors tend to be few and far between at nightfall and early evening. Yet, if fortune smiles upon you, you could catch an earthgrazer – a looooong, slow, colorful meteor traveling horizontally across the evening sky. Earthgrazer meteors are rare but memorable. Perseid earthgrazers can only appear at early to mid-evening, when the radiant point of the shower is close to the horizon.

The constellation Perseus, radiant of the Perseid meteor shower

From mid-northern latitudes, the constellation Perseus, the stars Capella and Aldebaran, and the Pleiades cluster light up the northeast sky in the wee hours after midnight on August nights. The meteors radiate from Perseus.

Cassiopeia and Double Cluster

Here’s a cool binocular object to look for while you’re watching the meteors. The constellation Cassiopeia points out the famous Double Cluster in northern tip of the constellation Perseus. Plus, the Double Cluster nearly marks the radiant of the Perseid meteor shower. Photo by Flickr user madmiked

General rules for Perseid-watching. No special equipment, or knowledge of the constellations, needed.

Find a dark, open sky to enjoy the show. An open sky is essential because these meteors fly across the sky in many different directions and in front of numerous constellations.

Give yourself at least an hour of observing time, for these meteors in meteor showers come in spurts and are interspersed with lulls. Remember, your eyes can take as long as 20 minutes to adapt to the darkness of night. So don’t rush the process.

Know that the meteors all come from a single point in the sky. If you trace the paths of the Perseid meteors backwards, you’d find they all come from a point in front of the constellation Perseus. Don’t worry about which stars are Perseus. Just enjoying knowing and observing that they all come from one place on the sky’s dome.

Enjoy the comfort of a reclining lawn chair. Bring along some other things you might enjoy also, like a thermos filled with a hot drink.

Remember … all good things come to those who wait. Meteors are part of nature. There’s no way to predict exactly how many you’ll see on any given night. Find a good spot, watch, wait.

You’ll see some.

Earth encounters debris from comet, via AstroBob

Earth encounters debris from comet, via AstroBob

What’s the source of the Perseid meteor shower? Every year, from around July 17 to August 24, our planet Earth crosses the orbital path of Comet Swift-Tuttle, the parent of the Perseid meteor shower. Debris from this comet litters the comet’s orbit, but we don’t really get into the thick of the comet rubble until after the first week of August. The bits and pieces from Comet Swift-Tuttle slam into the Earth’s upper atmosphere at some 130,000 miles (210,000 km) per hour, lighting up the nighttime with fast-moving Perseid meteors.

If our planet happens to pass through an unusually dense clump of meteoroids – comet rubble – we’ll see an elevated number of meteors. We can always hope!

Comet Swift-Tuttle has a very eccentric – oblong – orbit that takes this comet outside the orbit of Pluto when farthest from the sun, and inside the Earth’s orbit when closest to the sun. It orbits the sun in a period of about 133 years. Every time this comet passes through the inner solar system, the sun warms and softens up the ices in the comet, causing it to release fresh comet material into its orbital stream.

Comet Swift-Tuttle last reached perihelion – closest point to the sun – in December 1992 and will do so next in July 2126.

The radiant point for the Perseid meteor shower is in the constellation Perseus.  But you don't have to find a shower's radiant point to see meteors.  Instead, the meteors will be flying in all parts of the sky.

The radiant point for the Perseid meteor shower is in the constellation Perseus. But you don’t have to find a shower’s radiant point to see meteors. Instead, the meteors will be flying in all parts of the sky.

What is the radiant point for the Perseid meteor shower? If you trace all the Perseid meteors backward, they all seem to come from the constellation Perseus, near the famous Double Cluster. Hence, the meteor shower is named in the honor of the constellation Perseus the Hero.

However, this is a chance alignment of the meteor shower radiant with the constellation Perseus. The stars in Perseus are light-years distant while these meteors burn up about 100 kilometers (60 miles) above the Earth’s surface. If any meteor survives its fiery plunge to hit the ground intact, the remaining portion is called a meteorite. Few – if any – meteors in meteor showers become meteorites, however, because of the flimsy nature of comet debris. Most meteorites are the remains of asteroids.

In ancient Greek star lore, Perseus is the son of the god Zeus and the mortal Danae. It is said that the Perseid shower commemorates the time when Zeus visited Danae, the mother of Perseus, in a shower of gold.

Bottom line: The 2016 Perseid meteor shower probably feature a good show on in the predawn hours of August 11, 12, and 13. Astronomers produced a Perseid meteor outburst in 2016 on the night of August 11-12 (evening of August 11, morning of August 12), but we haven’t heard yet if the outburst occurred or who on Earth saw it.

Everything you need to know: Delta Aquarid meteor shower

Bruce McClure

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