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Royal Astronomical Society of New ZealandMeteors - "Shooting Stars" |
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Royal Astronomical Society of New ZealandMeteors - "Shooting Stars" |
This page will have information about some meteor showers
visible from the southern hemisphere
Further information on meteors will also be available at the
Comet and Meteor
Section web site.
Another useful source is Meteor Showers on Line.
A possible new meteor shower for
mid September.
A possible brief meteor shower at the
beginning of March
| Shower name | Month visible | Shower name | Month visible | Shower name | Month visible |
|---|---|---|---|---|---|
| gamma-Normids | March | Virginids | March | pi-Puppids | April |
| eta-Aquarids | April and May | Sagittarids | April to July | June Bootids | June |
| Group of 5 Showers | July and early August | Pisces Austrinids | Southern delta-Aquarids | ||
| alpha Capricornids | Southern iota-Aquarids | Northern delta-Aquarids | |||
| Northern iota-Aquarids | August | Piscids | September | Orionids Observing the Orionids |
October |
| Leonids Observing the Leonids |
November | alpha Monocerotids | November | Phoenicids | December |
| Geminids Observing the Geminids |
December |
Meteors are caused by small particles ranging in size from a grain of sand to a pea entering the Earth's atmosphere at high speed. Because of the speed, which can be between about 20 km/s and 70 km/s, the particles "burn up" in the upper atmosphere, leaving a visble incandescent trail. When the Earth moves through a stream of such particles left by a comet, a meteor shower may result.
Normally a small number of meteors can be seen each hour at night. During a shower the number visible may increase considerably with the meteors appearing to originate from a small area of the sky, called the radiant. This is a perspective effect due to the meteors travelling in parallel lines but as they approach the observer they appear to spread out. The shower is named after the constellation in which the radiant lies.
The information on this page is based on information from the International Meteor Organisation. Further details on meteor observing can be obtained from their web pages.
Contributed by Dennis Goodman
This 'shower' is believed to peak around 14-15 September. The radiant point is between the Hyades and the Pleiades in the constellation Taurus, near a 4.3 magnitude star.
The radiant is rather low for NZ observers, but nevertheless it will be worth watching to see if any meteors radiate from that point. I suggest watching from about 4 am on both September 14 and September 15 until dawn gets too advanced. Don't expect to see huge numbers - more likely just a few per hour, if any. This is not a confirmed radiant, so we are simply interested to see if there is any activity.
If recording observations, please note the start and end time of observing run, weather conditions and limiting magnitude (brightness of faintest stars visible). Count the number of meteors you can trace to come from the radiant point in Taurus. If they radiate from anywhere else, don't count them as a shower meteor.
Please send any observations to Dennis Goodman, P O Box 2214, Christchurch who will then on-send them to Stephen O'Meara and the American Meteor Society. If you wish to report by Email, send observations to the the webmaster. I will make sure they get passed onto Dennis Goodman.
The chart shows the sky near the possible radiant in Taurus. At 4.30 am the Pleiades will be close to due north form New Zealand with an altitude about 20° from the south of the South Island increasing to about 30° from the north of the North Island. The view is a southern hemisphere view. Stars to magnitude 5.5 are shown. Chart produced by GUIDE 8.0.
Provided by Alan Gilmore from IAU Circular 8079
Note, March 1.912+/-.0.010 UT is March 1, 21:53 =/- 24 minutes, that is March 2 at 9.53 am NZST. Thus the shower will not be visible from New Zealand nor Australia. At that time, and with the southerly declination of the radiant, it appears that South Africa may have the best view.
gamma-Normid meteors are similar to the sporadics in appearance, and for most of their activity period are virtually undetectable above this background rate. The peak itself is normally quite sharp, lasting for only a day or two either side of the maximum.
The Virginids maximum is just after full Moon. The radiant has a wide spread, some 15° in right ascension and 10° in declination.
The pi-Puppids are produced by Comet 26P/Grigg-Skjellerup. The hourly rate is variable, up to 40 an hour have been recorde. However 2001 may not be a good year as the next perihelion passage of Grigg-Skellerup is in October 2002.
This is a fine, rich stream associated with Comet 1P/Halley, like the Orionids of October, but it is visible for only a few hours before dawn essentially from tropical and southern hemisphere sites. The fast and often bright meteors make the wait for radiant-rise worthwhile, and many events leave glowing persistent trains after them.
A relatively broad maximum, sometimes with a variable number of submaxima, usually occurs in early May. ZHRs are generally above 30 for almost a week centred on the main peak. However with full Moon on May 7, the shower is is not well placed for watchers in 2001. The radiant culminates at about 08h local time.
The radiant has a wide spread, some 15° in right ascension and 10° in declination.
This shower made an unexpected return in 1998. Prior to 1998, only four definite returns of the shower had been detected, in 1916, 1921 and 1927. With no significant visual reports between 1928..1997, it was assumed no longer encountered the Earth.
The shower's parent comet 7P/Pons-Winnecke was last at perihelion in January 1996 and is next due in May 2002, and its orbit currently lies around 0.24 astronomical units outside the Earth's orbit at its closest approach, so we have no way at present to predict likely future activity. In 1998, high Bootid rates (50 -100+ per hour) were visible for more than half a day. The waning crescent Moon, just four days from new, will present no real problems.
Pisces Austrinids Southern delta-Aquarids alpha Capricornids
Southern iota-Aquarids
Northern delta-Aquarids
Notes on the July showers
The Aquarids and Piscis Austrinids are all streams rich in faint meteors, making them well-suited to telescopic work, although enough brighter members exist to make visual and photographic observations worth the effort too, primarily from more southerly sites.
The alpha-Capricornids are noted for their bright - sometimes fireball-class - events, which, combined with their low apparent velocity, can make some of these objects among the most impressive and attractive an observer could wish for. A minor enhancement of alpha-Capricornid ZHRs to about 10 was noted in 1995 by European IMO observers, although the Southern delta-Aquarids were the only one of these streams previously suspected of occasional variability.
Such a concentration of radiants in a small area of sky means that familiarity with where all the radiants are is essential for accurate shower association for all observing nights. Visual watchers in particular should plot all potential stream members seen in this region of sky rather than trying to make shower associations in the field. The only exception is when the Southern delta-Aquarids are near their peak, as from southern hemisphere sites in particular, rates may become too high for accurate plotting.
These showers are rich in faint meteors making them suitable for telescopic work. The new Moon will favour observation in 2001.
The Piscids can be observed from either hemisphere throughout September. There is some doubt as to when the Piscid peak occurs, or if there is only one.
The Orionids have several maxima apart from the main one. For
example a strong peak on October 17-18 has been observed in
Europe in 1993 and 1998. Observations are possible from midnight
on.
A weak shower, the epsilon Geminids, is nearly coincident with
the Orionids and have a peak October 18.
Further details on observing the Orionids
The Leonids derive from comet 55P/Tempel-Tuttle ;ast at perihelion in February 1998. A meteor storm was seen in 1999 in the region of the Canary Islands. High levels of activity are possible in 2001. From the Southern hemisphere the radiant rises after midnight.
In an outburst in 1995, this shower produced a rate of about 420 per hour - for 5 minutes! The whole outburst lasted about 30 minutes. The expected peak time for 2001 is well placed for viewing from New Zealand and Australia.
The phoenicid return in 1956 was impressive with about 100 per hour. Activity is otherwise very uncertain. The radiant is well placed for southern hemisphere observers
One of the finest annual showers but with a radiant well north of the equator. In the southern hemipshere the radiant appears around local midnight, even so this is a splendid shower of often bright, medium-speed meteors.