Major Meteor Showers in 2002
Major Meteor Showers in 2002
The year 2001 was a very productive one for meteor observers. For visual work, the Moon's interference was minimal during the maxima of most of the major showers. The big event, the Leonids, reached storm levels (ZHR>1000) with the Moon out of the sky. This year will be much more challenging. The Perseids are favored by a waxing crescent, but all of the other major showers are badly moonlit. A good display from the Geminids should be seen as soon as the waxing gibbous Moon sets on the early morning of December 14. The Leonids, anticipated to storm again on the morning of November 19, will be well worth watching despite a nearly full Moon. A couple of the other annual showers offer marginal prospects for interested observers. Here is a rundown of major meteor showers in 2002, with observing prospects for the Pacific Northwest (USA).
LYRIDS (maximum April 22, 10:30UT [3:30am PDT]) (radiant drift map)
The Lyrids are active from April 16-25, but only qualify as a major shower on the morning nearest maximum. The timing of maximum is good for West Coast viewers this year, but the waxing gibbous Moon will be a nuisance. The Moon will set at about 4:30am, just as morning twilight is beginning. However, it will be low in the sky, and should permit observation of a fair amount of meteors from an otherwise dark site.
Observers should plan on watching from about 3am until twilight becomes too bright. The radiant is highest in the late morning hours, and activity should be peaking. Normally, the Lyrids produce a peak ZHR of about 20. Occasionally, outbursts of up to 100/hour have been observed. Under this year's conditions, observers should expect peak rates of 5-15 Lyrids/hour along with a handful of sporadics.
ETA AQUARIDS (maximum May 5 [broad]) (radiant drift map)
This shower strongly favors the Southern Hemisphere, and although maximum ZHRs usually exceed 40, observers as far north as 45N would be lucky to see 10 meteors/hour from this shower. This year, moonlight interferes slightly on May 5, when the thick waning crescent rises at 3:36am PDT (from Portland). Because the radiant rises late in the morning, and attains an altitude of only 13 degrees by the beginning of morning twilight (~3:50am), visibility is brief on any single morning. However, the maximum tends to be broad and irregular, with ZHRs >30 from May 3-10. NW observers may wish to observe on a postmaximum morning, when the Moon will be completely out of the way, and continue watching until twilight becomes too bright. Viewing should begin around 3am. With the radiant low on the horizon, expect hourly rates between 5 and 10, with a roughly equal number of sporadics. The low radiant favors earthgrazer-type meteors, which often run "low, long and slow" along the horizon.
PERSEIDS (maximum August 12, 23h UT [4pm PDT]) (radiant drift map)
The Perseids are, without a doubt, the most popular annual shower for NW observers. The often warm and clear weather, combined with the Perseids' reliably high rates and long shower duration, make this stream an ideal if non-representative introduction to meteor observing.
A few Perseids are visible starting in mid-July, when the radiant is far from Perseus in Cassiopeia. During the last week of July, my 2001 observations indicated Perseid rates of about 3/hour. By August 7, ZHRs exceed 10. On August 11 a steep increase begins, with rates rising from 20/hour to about 50/hour on the morning of August 12. The maximum occurs during daylight this year for the West Coast. Late on the evening of August 12, at the end of evening twilight, the ZHR should still be around 80. Observed rates will initially be around 30/hour due to low radiant elevation, but may climb to 50-60/hour in the morning hours of August 13. On the morning of August 14, rates should be around 30/hour.
The above is what I expect from the Perseids, but it is important to note that few meteor showers perform exactly as expected. That is why amateur data continues to be valuable. With mostly Moon-free conditions surrounding the Perseid peak (the waxing crescent sets at around 10:50pm on August 12), this shower should be attractive to new meteor counters. Remember that the best rates will occur in the hours just before morning twilight (although anytime after midnight is a good time to watch, and the entire night of August 12/13 should be monitored closely). Sporadic (non-Perseid) rates will be high (10-20/hour) and will add greatly to the display.
ORIONIDS (maximum October 21 [broad]) (radiant drift map)
The Orionids produce rates of 5-15/hour for a week in mid-October, with occasional surges in activity that may reach 25 or even 50/hour. The shower's radiant near Betelgeuse is best-placed just before morning twilight. This year, the Full Moon will wipe out nights around the Orionid maximum. Short Moon-free periods will occur on the mornings of October 17 and 18. While Orionid rates may be quite low, there is always the chance of an outburst as occurred on these dates in 1993.
LEONIDS (maximum November 19, 10:40UT [2:40am PST]) (radiant drift map)
The 2001 Leonids produced North America's most spectacular meteor display in 35 years, and the stream should be at it again this year. An outburst on the morning of November 19 is a virtual certainty, although the intensity is very much in question. Observers will have to contend with a nearly full Moon, which will cut observed rates in half from even the darkest sites. North American observers, especially in the West, are pinning their hopes on the dust trail left by Comet Tempel-Tuttle's 1866 perihelion passage. That trail caused a storm over Australia and Asia in 2001, but the peak rates of ~3000/hour were about half those predicted by the most reliable forecasts. So far, the dust trail modelers have not weighed in with a revised forecast for 2002. A reasonable estimate would be a peak ZHR of ~4000 over North America at 2:40am PST on November 19. For the Pacific Northwest, radiant elevation will shave about 40% off the ZHR at that time, and then there is the effect of that bright Moon. From an otherwise dark, transparent site, this would equate to an observed rate of ~1000/hour, similar to the 2001 display. Of course, this is all intelligent speculation. We'll have to wait and see what the Leonids really do.
Interestingly, Europe and Africa should see an outburst from the 1767 trail that produced the 2001 storm over North America. While this event should peak at 8pm PST on November 18, several hours before the radiant rises for the Northwest, the display may last long enough to give us another nice display of earthgrazers from 11pm on, preceding our main event.
Observing the 2002 Leonids will be a challenge. Although much of the nation dodged the weather bullet in 2001, that might be too much to ask for again. Unlike last year's shower, this peak doesn't land on a weekend. Combined with moonlight, this may discourage travel plans. In any event, all amateur astronomers should try to see this shower. Several theorists have noted that it doesn't look like another meteor storm will occur within the next 50 years.
Experienced observers have had good success observing major showers during moonlit conditions. In order to see the highest rates, you still have to seek out the darkest feasible site. Search for clean, dry air. A high-altitude location would be ideal, but if there is snow on the ground this will exacerbate the effect of the Moon. Keep the Moon out of your field of view, blocked by a car or building if possible. But, wherever you end up, make an effort to see the 2002 Leonids.
GEMINIDS (maximum December 14, 10h UT [2am PST]) (radiant drift map)
The Geminids are possibly the most reliable of the annual showers. While the shower's overall duration is much shorter than that of the Perseids, there is a definite plateau of maximum activity. Rates typically peak at 100-120/hour; this high activity lasts for several hours. If clouds and/or moonlight don't interfere, a good display is assured. Unfortunately, that's a big if. Pacific Northwest weather is usually terrible in mid-December. This year, the predicted maximum occurs on the morning of December 14 at around 2am PST, just as the waxing gibbous Moon is about to set. Lucky cloud-free observers will then get several hours of exciting Geminid activity before morning twilight. The placement of the maximum on Saturday morning should encourage travel to find clear, dark skies. It is certainly possible to see 80-100 Geminids in a single hour, along with 10-20 non-Geminids, but only from a dark site. Even the couple of hours between midnight and moonset should provide a decent show.
For harder-core (or cloud-frustrated) observers, the Geminids are also worth watching for three mornings before and one morning after the peak. Pre-maximum mornings allow longer vigils, as the Moon sets earlier. Expected ZHRs are 10 on the morning of the 11th, 20 on the morning of the 12th, 40-50 on the morning of the 13th, and 10-20 on the morning of the 15th.
These are the best meteor observing opportunities in the year 2002, and represent the showers that will be most appealing to novice and intermediate observers. Of course, there is meteor activity every night of the year. Sporadic rates are low from mid-winter through June. In July, rates of random and minor-shower meteors pick up, and are high through the remainder of the year. In July and August, there are many meteors from radiants in Aquarius and Capricornus, including the major South Delta Aquarids (very badly moon-affected at maximum in late July). The minor Kappa Cygnids add a few slow, sometimes bright meteors to the Perseid display. In October and November, the Taurids produce a few meteors per hour, including an occasional fireball. For more information on meteor observing, check out the links below.
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