Friday

EarthSky’s meteor shower guide for 2011

Amplify’d from earthsky.org
Coming up in 2011

In 2011, if you’re in the northern hemisphere, the best time to watch meteors is late July and early August. Nights are warm, and two major showers – the Delta Aquarid meteor shower and the Perseid meteor shower – converge to put on a show. Watch in the first week of August to have moonless skies from midnight to dawn, the best time of night for watching meteors. This week (July 24-29), the moon is waning in the predawn sky, but it’s a slim moon, not casting much light, and some meteors might show up in its glare. The moon will be new, or between the Earth and sun on July 30. Afterwards, the moon will begin to wax again, but you’ll have an entirely moon-free sky after midnight during the first week of August. Full moon will come on August 13, a peak morning for the Perseids.

July 29, 2011 Delta Aquarids

Like the Eta Aquarids, this shower favors the southern hemisphere, and the tropical latitudes in the northern hemisphere. The meteors appear to radiate from the southern part of the sky. From northern temperate latitudes, the maximum hourly rate may reach 15-20 meteors in a dark sky. Unlike many meteor showers, this one doesn’t have a very definite peak, despite the date given above. Instead, these medium-speed meteors ramble along fairly steadily throughout late July and early August. An hour or two before dawn usually presents the most favorable view of the Delta Aquarids. Try watching in late July and early August, in the hours between midnight and dawn.

August 12 and 13, 2011 Perseids
And when we say August 12 or 13, we mean the morning hours after midnight – not that night. Unfortunately, the full moon will spoil 2011′s Perseid display, obscuring all but the brighter meteors, during the shower’s actual peak. But you will see Perseids in the weeks leading up to the peak, too, if you have dark skies. These typically fast and bright meteors radiate from a point in the constellation Perseus the Hero. You don’t need to know Perseus to watch the shower because the meteors appear in all parts of the sky. The Perseids are considered by many people to be the year’s best shower, and often peak at 50 or more meteors per hour – in years when the moon is out of the sky. However, 2011 is not a great year for the Perseids, because the moon is full on the expected peak date. The Perseids tend to strengthen in number as late night deepens into midnight, and typically produce the most meteors in the wee hours before dawn. These meteors are often bright and frequently leave persistent trains. Start watching for the Perseids in the first week of August. They will be building gradually to their peak. By the second week of August, the moon will begin interfering with the skies between midnight and dawn. On the mornings of August 12 and 13, you can still watch for some Perseid meteors to streak across this short summer night from midnight until dawn. Yet the full moon will interfere.

October 7 and 8, 2011 Draconids

The radiant point for the Draconid meteor shower almost coincides with the head of the constellation Draco the Dragon in the northern sky. That’s why the Draconids are best viewed from the northern hemisphere. However, the big and brilliant waxing gibbous moon makes 2011 a less than favorable year for watching this shower. The Draconid shower is a real oddity, in that the radiant point stands highest in the sky as darkness falls. Unlike many meteor showers, the Draconids are more likely to fly in the evening hours than in the morning hours after midnight. This shower is usually a sleeper, producing only a handful of languid meteors per hour in most years. But watch out if the Dragon awakes! On occasion, fiery Draco has been known to spew forth hundreds – if not thousands – of meteors in a single hour. Even if the predicted outburst comes in 2011, the shower must complete with the light of the waxing gibbous moon. The glare of moonlight is sure to obscure the 2011 Draconid shower, but you can try viewing it on the peak evenings of October 7 and 8.

October 20 and 21, 2011 Orionids

The rather large waning crescent moon obtrudes somewhat on this year’s Orionid meteor shower. Although the moon doesn’t rise till after midnight, the Orionids usually wait until the wee morning hours to pick up steam. Despite the moonlight, meteor enthusiasts may want to give the Orionids a try anyway. On a dark, moonless night, the Orionids exhibit a maximum of about 15 meteors per hour. These fast-moving meteors occasionally leave persistent trains and bright fireballs. If you trace these meteors backward, they seem to come from Orion’s Club, or north of Orion’s bright, ruddy star Betelgeuse. The Orionids have a broad and irregular peak that is difficult to predict. More meteors tend to fly after midnight, and the Orionids are typically at their best in the wee hours before dawn. The best viewing will probably be before dawn on October 21 or 22, though the waning crescent moon may somewhat tarnish this year’s Orionid display.

November 5, 2011 South Taurids

The South (and North) Taurids are perhaps best suited to die-hard meteor aficionados. The meteoroid stream that feeds the Taurids is very spread out and dissipated. That means the Taurids are extremely long lasting (September 25 to November 25), but usually don’t offer a lot more than about 7 meteors per hour, even on the South Taurids’ expected peak date of November 5/6. The big and bright waxing gibbous moon ruins the show during the evening hours on November 5, but if you’re a night owl, try watching after moonset, or in the wee hours after midnight on November 6.

November 11 and 12, 2011 North Taurids

This shower is long-lasting (October 12 – December 2) but modest, and the peak number is forecast at about 7 meteors per hour. Typically, you see the maximum numbers at around midnight to 1 a.m., when Taurus the Bull moves nearly overhead. This year, the bright waning gibbous moon shines right in front of the constellation Taurus, making 2011 an unfavorable year for watching these rather slow-moving but sometimes bright North Taurid meteors. The greatest numbers of North Taurid meteors come at late night and after midnight on the nights of November 11 and 12, but you might want to write off this year’s North Taurids because of the strong moonlit glare.

November 17, 2011 Leonids

Historically, the Leonids have produced some of the greatest meteor storms in history, with rates as high as many thousands of meteors per hour. These storms sometimes recur in cycles of 33 to 34 years. Most years, the Lion whimpers rather than roars, producing a maximum of perhaps 10-15 meteors per hour. Like the October Orionids, the Leonids ordinarily pick up steam after midnight and display the greatest meteor numbers just before dawn. This year, however, the last quarter moon will be shining near the radiant point of the shower in the constellation Leo. The unwelcome presence of the moon is sure to dampen this year’s Leonid display. If you’re game, you can try watching from late night November 17 till dawn November 18, though the moonlit glare will subdue the 2011 Leonid meteor shower.

The waning gibbous moon makes 2011 a rather unfavorable year for watching the Geminids, the year’s grand finale for the major meteor showers. As a general rule, it’s either the August Perseids or the December Geminids that give us the most prolific display of the year. In 2011, moonlight obscures both showers. Unlike many meteor showers, you can usually start watching the Geminids by 9 or 10 p.m. This year, however, the moon rises at mid-evening and shines all the way until daybreak. On a dark, moonless night, the Geminid meteor shower often produces 50 or more meteors per hour. The best viewing of these often bright, medium speed meteors should be after midnight on December 14 and 15, but the bright moon will greatly lessen the number of visible Geminid meteors in 2011
December 13 and 14, 2011 Geminids


Earlier in 2011

January 4, 2011 Quadrantids

When we say January 4, we mean in the wee hours before dawn, not that night. Because the new moon also happens on January 4, we’re guaranteed of dark skies for this year’s Quadrantid shower. Although the Quadrantids can produce over 100 meteors per hour, the sharp peak only lasts for an hour or two, and doesn’t always come at an opportune time. In other words, you have to be in the right spot on Earth to view this meteor shower in all its splendor. If this year’s forecast proves correct, eastern Europe and western Asia will be in the right place and North America will miss out. However, meteor showers are notorious for defying predictions, so it may be worth a try. Face the general direction of north-northeast, but take in as wide an expanse of sky as possible. Watch from about 2 a.m. till dawn.

April 22, 2011 Lyrids

The Lyrid meteors – April’s “shooting stars” – tend to be bright and often leave trails. About 10-20 meteors per hour at peak can be expected in years when the moon is out of the way. Plus, the Lyrids are known for uncommon surges that can sometimes bring the rate up to 100 per hour. Those rare outbursts are not easy to predict, but they’re one of the reasons the tantalizing Lyrids are worth checking out. The radiant for this shower is in the constellation Lyra, which rises in the northeast at about 10 p.m. Unfortunately, in 2011, the waning gibbous moon obstructs the view in the late night and morning hours, the best time to watch the Lyrid shower. As a general rule, the greatest number of Lyrid meteors fall in the dark hours before dawn. The optimal night will probably be from late night April 22 until dawn April 23, though the night before (April 21/22) may be almost as good. The glare of the waning gibbous moon will wipe out all but the brighter Lyrid meteors. But seeing even one meteor scooting along in the light of the moon is worthwhile!

May 5, 6, and 7, 2011 Eta Aquarids

This shower has a relatively broad maximum but is expected to show the greatest number of meteors before dawn on May 6. Fortunately, the thin waxing crescent moon will set in early evening, leaving dark skies for this year’s Eta Aquarid show. At northerly latitudes – like in the northern states and Canada – the meteor numbers are few and far between. In the southern half of the US, 10 to 20 meteors per hour may be visible in a dark sky. Farther south – like in the southern hemisphere – the meteor numbers increase dramatically, perhaps two to three times more Eta Aquarid meteors streaking the southern skies. For the most part, this is a predawn shower. The radiant for this shower appears in the east-southeast at about 4 a.m. and the hour or two before dawn offers the most meteors. The broad peak to this shower means that some meteors may fly in the dark hour before dawn for a few days before and after the predicted optimal date. Although the most meteors will probably rain down on May 6 before dawn, the day before or after may offer a sprinkling of Eta Aquarid meteors as well.

Most important: a dark sky. Here’s the first thing – the main thing – you need to know to become as proficient as the experts at watching meteors. That is, to watch meteors, you need a dark sky.
Know your dates and times. You also need to be looking on the right date, at the right time of night. Meteor showers occur over a range of dates, because they stem from Earth’s own movement through space. As we orbit the sun, we cross “meteor streams.” These streams of icy particles in space come from comets moving in orbit around the sun. Comets are fragile icy bodies that litter their orbits with debris. When this cometary debris enters our atmosphere, it vaporizes due to friction with the air. If moonlight or city lights don’t obscure the view, we on Earth see the falling, vaporizing particles as meteors.
What to bring. You can comfortably watch meteors from many places, assuming you have a dark sky: your back yard or deck, the hood of your car, the side of a road. If you want to bring along equipment to make yourself more comfortable, consider a blanket or reclining lawn chair, a thermos with a hot drink, binoculars for gazing along the pathway of the summer Milky Way. Be sure to dress warmly enough. Even the summer nights can be chilly, especially in the hours before dawn when the most meteors should be flying.

In 2011, the moon gets in the way of the April Lyrids, August Perseids, October Draconids, October Orionids, November North Taurids, November Leonids, and December Geminids. Moon-free nights greet the January Quadrantids, May Eta Aquarids, and July Delta Aquarids. Some moon-free viewing time is in store for the November South Taurids. Our almanac page provides links for access to the moonrise and moonset times in your sky.



Tips for watching meteors



Most important: a dark sky.
Here’s the first thing – the main thing – you need to know to become as proficient as the experts at watching meteors. That is, to watch meteors, you need a dark sky.


Know your dates and times. You also need to be looking on the right date, at the right time of night. Meteor showers occur over a range of dates, because they stem from Earth’s own movement through space. As we orbit the sun, we cross “meteor streams.” These streams of icy particles in space come from comets moving in orbit around the sun. Comets are fragile icy bodies that litter their orbits with debris. When this cometary debris enters our atmosphere, it vaporizes due to friction with the air. If moonlight or city lights don’t obscure the view, we on Earth see the falling, vaporizing particles as meteors.


What to bring. You can comfortably watch meteors from many places, assuming you have a dark sky: your back yard or deck, the hood of your car, the side of a road. If you want to bring along equipment to make yourself more comfortable, consider a blanket or reclining lawn chair, a thermos with a hot drink, binoculars for gazing along the pathway of the summer Milky Way. Be sure to dress warmly enough. Even the summer nights can be chilly, especially in the hours before dawn when the most meteors should be flying.



Are the predictions reliable?
Although astronomers have tried to publish exact predictions in recent years, meteor showers remain notoriously unpredictable. Your best bet is to go outside at the times we suggest, and plan to spend at least an hour reclining comfortably while looking up at the sky.


In 2011, the moon gets in the way of the April Lyrids, August Perseids, October Draconids, October Orionids, November North Taurids, November Leonids, and December Geminids. Moon-free nights greet the January Quadrantids, May Eta Aquarids, and July Delta Aquarids. Some moon-free viewing time is in store for the November South Taurids. Our almanac page provides links for access to the moonrise and moonset times in your sky.


Peak dates are derived from data published in the Observer’s Handbook by the Royal Astronomical Society of Canada and Guy Ottewell’s Astronomical Calendar.



Animation Credit: NASA MSFC


Remember, meteor showers are like fishing. You go, you enjoy nature … and sometimes you catch something.


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