Major Meteor Showers in 2008
2007 was an excellent year for meteor observers. While the Alpha Aurigid outburst was very short-lived and relatively weak (not to mention Moon-plagued), favored observers saw some very impressive meteors in a splendid confirmation of predictions. The Perseids and Geminids were their reliable selves, and once again the Orionids were stronger than normal.
In 2008, most of the major showers have moonlight problems. In particular, the Geminid peak falls right when the nearly full Moon dominates the winter sky. It's hard to imagine worse observing conditions for that shower. The Orionids don't fare much better, with the Moon at last quarter during their peak. In view of the exciting Orionid performances in 2006 and 2007, the Orionids should be on anyone's observing list just the same. Conditions are excellent for serious Perseid observing on the peak morning of August 12. Even though the Moon is a fat waxing gibbous, it is far to the south and will set early enough to allow several hours of observing before morning twilight brightens the sky. These are the prime hours for meteor observing--possibly the best of the year! I'm especially looking forward to them because if the timing falls just right this is the year that will produce hourly Perseid counts of 100+ from my location on the West Coast of North America. 2004 was awesome; 2008 could be as well.
It is a mixed bag for the lesser-observed showers. The January Quadrantids have a very short and sharp maximum that is often missed due to the weather. This year, the only moonlight interference is from a rather slim waning crescent. April's Lyrids are badly moonlit. The Eta Aquarids in early May (while difficult to observe due to the southerly radiant and its proximity to the Sun) are moon-free. The Moon interferes somewhat with the peak of the South Delta Aquarids, but there will still be some interesting late-July observing from dark sites. The Taurids are well worth watching in late October and early November for a possible enhancement of numbers and/or fireballs. The Leonids have proven to be quite complex, but whatever they do this year will be difficult to observe due to the proximity of a bright, glaring Moon.
Don't forget to consider the effect of radiant elevation when planning an observing session. Even if a shower is near its activity peak, you won't see a thing from it if the radiant is below your local horizon. In the case of a strong shower, you may expect a (very) few long "earthgrazing" meteors when the radiant is near the horizon, but even when the radiant has reached an elevation of 30 degrees you will only see half as many meteors as you would if it were at your local zenith. Most shower radiants are highest during local morning hours, often just before twilight begins. That's usually when you want to observe, although occasionally a rising Moon or a sharp activity peak will suggest an earlier time. See "WHEN TO WATCH" below.
I mainly get questions about "when to watch" and "where to look". "Where to look" is usually fairly easy: center your field of view high in the darkest, least-obstructed part of your sky. If you have tall trees or an overpowering city light dome in one direction, you probably should face another direction. You don't have to look right at the shower's radiant. Indeed, you'll probably see fewer meteors if you do. But it's also nice and productive to keep the radiant somewhere within the field of view. If there's a bright Moon in the sky, keep it out of your field of view or try to block it with something, like a tree or a car or a chair...
WHEN TO WATCH: For each shower, I list the shower's name and a "Predicted Maximum". This is when THE SHOWER should be at its maximum activity, whether or not you are in a position to view it. If this maximum time happens to coincide with a time when it's clear and dark and the radiant is high in your sky, you'll probably be a happy camper. However, life usually involves compromises. So, for each shower I've included a paragraph titled "WHEN TO WATCH". This is my take on the best viewing window for each shower. These times are generally valid for all of North America and are given as local time (i.e., you don't have to worry about converting for your time zone). It may be worth looking up the beginning of astronomical twilight for your location on a given date; this will give you an idea of how late you may observe into the prime morning hours.
Vagaries of meteor activity, your personal ability to perceive meteors, and local sky conditions all have a dramatic effect on the rates you observe. Sky conditions to consider include weather and light pollution. If you can't see the summer Milky Way in Cygnus on a moonless night when this region of the sky is overhead, you probably won't see much from even the strongest annual showers. Clear, dark skies are essential for observing meteors. More shower meteors are visible from a dark site, and sporadic (random) meteor rates are enhanced greatly.
QUADRANTIDS
Predicted Maximum: January 4, 6:40 UT (= Jan. 3, 10:40pm PST; = Jan. 4, 1:40am EST)
Moon: Waning Crescent (minor interference)
WHEN TO WATCH: North American observers should cover the morning of Friday, January 4, from about 1:00am until the beginning of morning twilight.
The peak of this shower doesn't last long, and is notoriously variable in strength and timing and duration. Regardless of the timing of the peak, the radiant has to be above the horizon for you to see anything. If you live south of 40 degrees north latitude, keep to the morning window indicated above under "When to Watch". The East Coast of North America and perhaps Western Europe will be favored. Observers above 50 degrees north find the radiant low but well above the horizon throughout the evening hours. If you've got the guts and the stamina and the cold-weather gear, it may be worth it to start your observing session earlier, especially in the western half of North America. Peak observed rates will probably be 20-40 Quadrantids per hour, maybe up to 80 if the peak hits just right for your location. Obviously, you need clear and dark skies or you're not going to see much of anything.
Quadrantids are medium-velocity meteors, and some bright ones are often visible around the time of maximum activity. The radiant is in a rather blank area surrounded by the constellation figures of Bootes, Hercules, Draco and Ursa Major (see the radiant map). Off-maximum nights only produce a few shower members; the shower has a very short duration from about January 1-5. The morning hours are often fairly rich in sporadic (non-Quadrantid) meteors, especially if your skies are nice and dark.
Note: No dice on the Quadrantids at my place; really horrible weather once again...
LYRIDS
Predicted Maximum: April 22, ~4:00 UT (= Apr. 21, 9:00pm PDT; = Apr, 22, 12:00am EDT)
Moon: Waning Gibbous (major interference)
WHEN TO WATCH: It's difficult to recommend this shower this year due to the bright moonlight. On the evening of Monday, April 21, there is about 1 hour of darkness before the Moon rises in most locations, but the radiant is pretty low at that time. The radiant altitude is better from midnight until the beginning of morning twilight on Tuesday, April 22, but the Moon will be glaring. Peak observed rates will probably be about 5 Lyrids per hour.
Lyrids produce fairly fast meteors with a reputation for being faint on average. This shower is generally weak but the peak is variable in strength, timing and duration. There have been a few exceptional displays in the past, and there are some predictions of strong Lyrid returns in the future. Sporadic meteor activity is generally low at this time of the year.
ETA AQUARIDS
Predicted Maximum: May 5 (broad)
Moon: New (no interference)
WHEN TO WATCH: The broad maximum of this shower means that you're not pinned down to a single morning. That's a really good thing for me, as surprisingly the weather is often awful in early May here in Oregon. Any morning from Sunday, May 4 through Wednesday, May 7 might produce interesting results. Or not... See below for an explanation of the unique challenges of observing this shower.
This shower is better for Southern Hemisphere observers, but is a bit difficult for everyone. The key is to watch during the last hour or so before twilight gets really bright. In terms of local time this depends on your latitude and also on your longitude with respect to the center of your time zone. Check an almanac or planetarium software. At latitude 42.6 degrees North, I've had my best results from about 3:40-4:40am local daylight time.
The Eta Aquarids would produce maximum rates of >50 per hour if we could see them with the radiant high in a dark sky. In the northern temperate latitudes, we don't get close to that. We get just a small taste of them in an intricate dance just before dawn. At 40 degrees North, the radiant is only about 15 degrees up when twilight begins. If I could get those conditions for an hour, I might see 10-15 ETAs. However, everything's changing. Before that time, there are fewer shower members visible because the radiant is lower. After that time, the radiant is higher and rates would keep rising but for the onrush of twilight. You're fortunate indeed if you see 10 ETAs in an hour, along with about 5 sporadic (random) meteors.
The low radiant elevation means that the earliest ETAs you see will be "earthgrazers": long, relatively slow and often tracing paths along the horizon. Bright earthgrazers are spectacular. Unfortunately, because of their greater distance from the observer, low earthgrazers tend to be faint. As the radiant gets a bit higher, the ETAs take on more of their typical appearance: fast meteors, bright on average and often leaving a glowing train. You'll only catch a few of them, though, because dawn is approaching. This shower seems to fluctuate irregularly, and you could easily hit either a spurt or a lull during the all-too-brief observing windows.
Note: I got in an hour of observing for the Eta Aquarids on May 5, and saw 9 ETAs along with 9 other meteors. See my Observing Log for details.
SOUTH DELTA AQUARIDS
Predicted Maximum: July 27 (broad)
Moon: Waning Crescent (minor to moderate interference)
WHEN TO WATCH: 1am-4am on any morning between Monday, July 28 and Wednesday, July 30.
The South Delta Aquarids are barely a major shower from 40 degrees N. They are part of a complex of radiants in Aquarius, Capricornus and Piscis Austrinus, all of which combine with sporadic and early Perseid activity to provide a nice display of meteors on moonless mornings in late July. The stream normally produces about 5-10 meteors/hour, with overall activity of about 30/hour under good conditions. Good conditions are really important; you won't see much from the city. On the other hand, dark sites in the Southern Hemisphere could produce exceptional rates. From the Northern Hemisphere, this is strictly a morning shower, and the radiant never gets very high.
The South Delta Aquarids are medium-speed meteors, and tend to be faint on average. Meteors from this stream are easily confused with those of several minor showers with nearby radiants. The Piscis Austrinids have a radiant near the bright star Fomalhaut. A weak, diffuse radiant called the "anthelion" or "eclipticids" is also nearby. Farther west is the Alpha Capricornid radiant, which produces slower, often impressive meteors. You may not be able to assign every shower meteor to its correct radiant, but that doesn't mean you can't enjoy the show!
PERSEIDS
Predicted Maximum: August 12, 11:30 UT [= Aug. 12, 4:30am PDT; = Aug. 12, 7:30 am EDT])
Moon: Waxing Gibbous (moderate interference)
WHEN TO WATCH: Tuesday morning, August 12, from about 1:00 am until morning twilight gets too bright.
The Perseids are probably the most-watched annual meteor shower. The shower has a very long duration, from about July 15 through August 25. The shower is most interesting around its peak on August 12 or 13. This year, the peak comes on August 12 because of the leap year. The radiant is above the horizon the entire night for observers north of latitude 32N, but it is fairly low at the end of evening twilight. Evening Perseid rates are fairly low, and the bright Moon makes things worse this year. The real meat of the show comes during the predawn hours when the Moon is down and the radiant is high.
Predawn rates for observers with truly dark skies may exceed 100 Perseids per hour (West Coast of North America and/or Eastern Asia may be favored this year), with a nice sprinkling of sporadic and minor shower meteors added to the mix. Adjacent mornings from August 10 through August 13 are well worth watching, although rates will be significantly lower.
Perseids are fast meteors and tend to be fairly bright on average. An occasional fireball is seen.
Update: I watched on the mornings of the 11th, 12th, and 13th, and the show did not compare to the previous "leap year" peaks. I averaged 66 Perseids/hour on August 12. However, it looks like there was an unexpected, short-lived outburst over Europe early on August 13. My reports are available in my Observing Log.
ORIONIDS
Predicted Maximum: October 21 (broad and irregular)
Moon: Last Quarter (major interference)
WHEN TO WATCH: From about 1:00 am until twilight gets too bright, on any morning between Monday, October 20 and Friday, October 24.
The Orionids are capable of producing interesting activity from October 17-25. Maximum rates seen from a dark site may reach 20-25 per hour, but sometimes there are lulls even around the traditional maximum of October 21. Recently, the shower has been much more exciting. In 2006, rates were much higher than expected for several mornings around the peak. 2007 also saw at least a couple of mornings of enhanced activity. It is unknown whether 2008 will continue the pattern. The Moon will definitely put a damper on things this year, and will make finding a dark site with clean air that much more important.
The Orionids are fast meteors, perhaps a bit faint on average but capable of producing fireballs. The 2006 outburst featured brighter-than-normal Orionids. Note that the radiant is north of Betelgeuse and not right in the middle of Orion. A minor shower called the Epsilon Geminids has a nearby radiant that can cause confusion, but usually produces only 1-2 meteors per hour. Early activity from the Taurids can produce a few nice, slow meteors from radiants farther west. Finally, 5-15 sporadic meteors are usually visible each hour from dark sites.
TAURIDS
Predicted Maximum: Very broad maximum in early November
Moon: Waxing Crescent (minor interference)
(radiant map from IMO--two branches of this shower are NTA and STA)
WHEN TO WATCH: Any clear night during the last few days of October or the first week of November, from about 10pm to 4am local daylight time.
The Taurids produce maximum rates of about 5-10/hour. The shower has a complex double radiant. For 2008, it has been suggested that there may be an increase in the number of bright and/or fireball-class Taurids. Taurids are rather slow meteors; bright ones are often vividly colored and may be spectacular. Usually, they are noticed casually while undertaking other observations. This year's display may or may not be worth watching in and of itself; the Taurids are included here to give fair warning.
LEONIDS
Predicted Maximum: November 17, 9:00 UT (=Nov. 17, 1:00am PST; =Nov. 17, 4:00am EST)
Moon: Waning Gibbous (major interference)
WHEN TO WATCH: I wouldn't recommend the Leonids for casual observers this year. Activity will probably be low, and if there are spurts or mini-outbursts the bright Moon will interfere. The radiant is best placed from about 2am until the beginning of morning twilight; the radiant is below the horizon and the shower unobservable during the evening hours. The Leonids are expected to be most active on the mornings of Monday, November 17 and Tuesday, November 18.
Update: Jeremie Vaubaillon has done some stream modeling that does predict a couple of activity enhancements for the Leonids in 2008. The first would come on November 17 at 1:32 UT (equivalent to 8:32pm EST and 5:32pm PST on November 16--this outburst would not be visible from North America). The second would come on November 18 at 21:38 UT (equivalent to 4:38pm EST and 1:38pm PST--neither would this one). For more information, see this page.
The Leonids are very fast meteors. The shower is active at a low "background" level for about a week from November 14-21.
GEMINIDS
Predicted Maximum: December 13, ~23:00 UT (=Dec. 13, 3pm PST; =Dec. 13, 6:00pm EST)
Moon: Full (major interference)
WHEN TO WATCH: The Geminids have a fairly broad maximum, so viewing should be productive during the morning hours of Saturday, December 13 and again for the entire night of December 13/14 (late Saturday evening into Sunday morning). The Moon will be a huge fly in the ointment this year; clean, clear air will help a bit. The Geminids tend to be brighter just after maximum activity, pointing to late Saturday evening and early Sunday morning as the best bet.
The Geminids are accessible from the entire Northern Hemisphere and from many Southern Hemisphere locations as well. The radiant is highest in the sky at around 2am, but from mid-northern latitudes it is at a decent elevation from around 10pm until the beginning of morning twilight. The Geminids can produce observed rates of up to 100/hour at maximum, but this year the Moon will allow us to see only a bare fraction of the show.
Geminids are medium-speed meteors. Most of them don't leave glowing trains, but the brighter ones are often colored (yellow, green and blue are most common).
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Other Sources of Meteor Activity
The major showers listed here are fairly reliable and occur every year. However, meteor activity is visible on any clear night. Random sporadic meteors, minor showers, and major showers near the beginning or end of their activity period all contribute to this "background". For the Northern Hemisphere, there is a general pattern of lower rates during the first half of the year and higher rates during the second half, but rates vary greatly from hour to hour, day to day, and observer to observer. Occasionally, unexpected high activity occurs. It is up to the observer to objectively describe what was seen. In many cases, high activity may be ascribed to randomness. At other times, many of the meteors seen may be attributed to a common radiant.
There are some periodic, irregular, and hypothetical showers that could produce surprises during 2008. The meteorobs mailing list is a good way to keep track of predictions and developments "beyond the majors".
Other Meteor Shower Info.
Outside Links
General shower attributes, radiant maps and predicted times of maximum are adapted from the International Meteor Organization's 2008 Meteor Shower Calendar. All on-site text and contents are Copyright 2007 by Wes Stone and may be reproduced for not-for-profit use so long as credit is given.
