Last Updated:
2009 Mar 28 21:51 UTC
Source file:
forthcoming_meteors.txt
|
Last Updated: |
|
Contents
|
Meteor Activity in 2009Edited by Tony MarkhamMoonlight conditions for observing the major meteor showers during 2009 will be more favourable than in 2008. The Quadrantids, Lyrids, Orionids, Leonids and Geminids all peak close to New Moon, although the Eta Aquarids and Perseids are less favourable. The Delta Aquarids, Alpha Capricornids, Taurids and Ursids will suffer some moonlight interference. 2009 also offers the possibility of seeing enhanced Leonid activity. Quadrantids max Jan 03d12h UTChart. The Quadrantid radiant, lying at Dec +50, is circumpolar for observers north of latitude 40 N. The radiant is at its lowest altitude at around 20h local time and is highest at the end of the night. The maximum is usually rather narrow, with the predicted time favouring observers in North America. Observers in western Europe will probably see their best rates around dawn on Jan 3rd. The Moon will be a near First Quarter and thus absent from the morning sky.VirginidsAfter the Quadrantids, night time meteor rates are rather low for northern hemisphere observers. However, from mid February to early May there are a number of minor showers, collectively referred to as the Virginids, whose radiants lie close to the ecliptic. Examples include the Delta Leonids (max Feb 26), the Alpha Virginids (max Apr 11-12) and the Gamma Virginids (max Apr 14). Peak rates generally occur in early April. New Moon in 2009 occurs on Feb 25, Mar 26 and Apr 25.Lyrids max Apr 22d10h UTChart. Lyrid activity can be seen from Apr 18-25 each year. With New Moon occurring on Apr 25, the Lyrids will be very favourably timed in 2009. The Lyrids are the main night time meteor shower of the spring months for northern hemisphere observers. Although they don't usually produce observed rates comparable with major showers that occur later in the year, the Lyrids do stand out relative to the low background activity of the spring months. Some intense but brief Lyrid outbursts have occasionally been seen, such as in 1982.For observers at northern latitudes, the Lyrid radiant is above the horizon all night, although it is fairly low at the start of the night. The highest Lyrid rates are usually to be seen when the radiant is highest in the sky late in the night. Eta Aquarids max May 4This shower is active from late April to mid May and produces higher peak ZHR values than do the Lyrids. However, while easy to observe from the southern hemisphere and from the tropics, for observers in northern Europe dawn is approaching before the radiant reaches a reasonable altitude. Thus observers at northern latitudes can only expect to see low observed rates.In 2009, the Eta Aquarid peak occurs midway between First Quarter and New Moon, so dark skies will, at best, be limited to a short interval between moonset and dawn. The radiant is in northern Aquarius, at RA 22h20m, Dec -01. Daytime showersFor observers at northern latitudes the Eta Aquarids are almost a daytime-only shower. However, active throughout May and June are several showers whose radiants are only above the horizon during daylight hours (although in a few cases, some activity may be detectable late in the night by observers in tropical latitudes). Consequently observation of these showers is limited to radio methods. ZHR and radiant information is generally poorly known. The most active of these showers appear to be the May Arietids (max May 16), the Omicron Cetids (max May 20), the Arietids (max Jun 7), The Zeta Perseids (max Jun 9) and the Beta Taurids (max Jun 28).June BootidsThis shower produced an unexpected outburst in 1998, with a broad peak during June 27-28. Another outburst was seen on 2004 June 23. Although several outbursts from this shower were seen in the early 20th century, these latest outbursts were unexpected as the Earth now passes some distance from the orbit of the particles which produced the earlier outbursts. The parent comet 7P/Pons-Winnecke was at perihelion on 2008 Sep 26, but there is no evidence that recent outbursts have been related to the position of the comet. It is worthwhile monitoring this shower's activity however in case further outbursts occur.In 2009 the above period is in the interval between New Moon and First Quarter. It is worth noting, however, that for observers at northern latitudes, the Moon, when present, will be low in the sky and so any negative influence on sky darkness will be reduced. July Minor ShowersNight-time sporadic activity picks up in July. Among the minor showers sometimes listed are the Alpha Cygnids, which are active throughout the month and into early August (radiant 21h00m, +48) and the Lacertids, which are active later in the month (radiant 22h05m, +37). Neither shower seems to have any clearly defined maxima. Full Moon in 2009 occurs on July 7, with New Moon occurring on July 22.Aquarid/Capricornid complexChart. This group of showers includes the Alpha Capricornids (max Aug 2), the Delta Aquarids-N (max Aug 5-9), the Delta Aquarids-S (max July 28-29), the Iota Aquarids-S (max Aug 6-7) and the Piscis Australids (max July 31). Except for the Delta Aquarids-S, the peak ZHRs are all below 10 per hour. The proximity of the radiants to each other, together with their motion from night to night means that visual observers must take great care to distinguish between the individual showers. The Alpha Capricornids have been noted for producing a number of slow moving flaring fireballs.With First Quarter in 2009 occurring on July 28 and Full Moon on Aug 6, the Delta Aquarid-S peak will be fairly favourably timed, but the other showers will be more seriously affected. Perseids max Aug 12d15h UTChart. Despite not producing peak rates as high as those of the Geminids, the Perseid meteor shower remains the favourite for most observers. This is because, in addition to being rich in bright and trained meteors, it also occurs during summer in the northern hemisphere as opposed to the cold nights of December for the Geminids. Perseid activity can be seen from the last week of July through to the third week of August. The highest observed rates on any given night are likely to be seen when the radiant is highest in the sky late in the night.Moonlight conditions in 2009 will be unfavourable for the early Perseids. With the Moon approaching Last Quarter by the night of maximum, circumstances improve for observers at lower northern latitudes, but less so for those at more northerly latitudes for who the Moon will be slow to disappear from the evening sky. August Minor ShowersSporadic activity is quite high in August and numerous minor showers have been reported as being active. Many of them are probably spurious, with some of their supposed members being misidentified Perseids and late members of the Aquarid/Capricornid complex.The more reliable showers include the Alpha Aurigids, which reach maximum late in the month (radiant RA 04h56m , Dec +43), and the Kappa Cygnids which reach maximum on Aug 20 (radiant 19h20m, +55) and often produce fireballs. Some sources also list an Iota Aquarid-N maximum on Aug 20 and a second Kappa Cygnid maximum on Aug 26. Full Moon in 2009 occurs on Aug 6, with New Moon occurring on Aug 20. Minor Showers in SeptemberSporadic activity is also high in September and, again, numerous minor showers have been reported - although not as many as for August, probably because less observers are usually active. The more reliable minor showers include the Alpha Aurigids (continuing from August), the Beta Cassiopeids (max Sep 1-6, radiant 00h05m, +63), the Epsilon Perseids (max Sep 3-7, radiant 04h10m, +37), the Delta Aurigids (max Sep 8, radiant 04h00h, Dec +47) and the Piscids (max Sep 8-9, radiant 00h36m, +07 ; max Sep 21, radiant 00h24m, +00). Full Moon in 2009 occurs on Sep 4, with New Moon occurring on Sep 18.October Camelopardalids max Oct 5-6 ?In 2005 and 2006, enhanced meteor activity from Camelopardus was recorded on video around this date. On neither occasion were there visual records of high activity, although the bright nearly Full Moon would have made observation very difficult in 2006. If this is an annual shower and it occurs at the same solar longitude each year, then it might be seen again around 19h-21h30m UT on 2009 Oct 5. This would favour observers at Asian longitudes, but it would be also be worthwhile observers at other longitudes monitoring for activity given the vagueness of the details reported to date. Moonlight circumstances will be unfavourable, with Full Moon having occurred on Oct 4.Giacobinids (Draconids) max Oct 8-921P/Giacobini-Zinner, the parent comet of this shower, passed through perihelion in July 2005, with some enhanced activity been reported when the Earth passed close to the comet's orbit at around 17h UT on Oct 8 2005. With the comet being well past perihelion, little or no activity is likely to be seen in 2009. The radiant, at RA 17h23m, Dec +57, lies near the head of Draco.Orionids Max Oct 20-24Chart. Conditions for Orionid observing will be very favourable in 2009. Orionid activity lasts from Oct 14-31, with a broad maximum occurring between Oct 20 and Oct 24 - however, even within this period there will be several peaks and troughs in the activity levels. The Orionids sometimes brings surprises such as the unusually high rates seen during the night of 2006 Oct 21-22. There were also indications of enhanced rates in 2008.The radiant position at maximum is RA 06h24m , Dec +15 (on the border of Gemini and Orion) but actually appears quite diffuse since it consists of a number of sub-centres, as shown by the chart, whose combined activity can give the impression of the radiant remaining almost stationary for several days. In 2009, New Moon occurs on Oct 18 and First Quarter occurs on Oct 26th. With the Orionid radiant not rising until mid evening and being highest in the sky late in the night, moonlight will not be a problem. Taurids Max Nov 7Chart. Activity lasts throughout October and November, with a broad maximum in early November. Observed rates are far from spectacular, but some observers report that the shower produces a good percentage of fireballs. Indeed a good number of bright Taurids were reported in 2005. Some Taurid activity will also be visible during the Orionid watches of October and the Leonid watches of November. The Taurid radiants are highest at around the middle of the night.The 2009 maximum is fairly favourably timed. Full Moon occurs on Nov 2, but the Moon will be quickly disappearing from the evening sky as we pass through the broad maximum. Leonids max Nov 17d 22hUT?Chart. Leonid activity last from Nov 14-20 each year. The Leonids produced storm level activity for observers at favoured locations in 1999, 2001 and 2002.It had been assumed that we had encountered all of the significant Leonid filaments. However, in 2008 the Earth passed close to a filament of material ejected at the 1466 return of the parent comet, resulting in rates being enhanced to around normal Perseid levels. A closer approach to this filament is predicted to occur in 2009 at around Nov 17d 22h UT, favouring observers at Asian longitudes. Observing conditions will be favourable in 2009 with New Moon occurring on Nov 16. The Leonid radiant rises in the late evening and is highest in the sky around dawn. Geminids max Dec 14d00h UTChart. Although the Geminids were overshadowed by the enhanced Perseid activity of the early 1990s and the enhanced Leonid activity of 1998-2002, the Geminids are the shower that produce the highest reliable rates year on year and only lose out in popularity to the Perseids due to the colder December nights. Geminid activity can be seen from Dec 7-16. Results from recent years have shown the peak ZHR to be over 100 and to remain above 70 per hour for about 24 hours - and the shower's profile is evolving from year to year. The Geminids are typically rich in bright meteors, but produce few trained meteors. The radiant is highest at about 02h local time and for observers at northern temperate latitudes is above the horizon all night.Moonlight conditions are favourable for the Geminids in 2009 with Last Quarter occurring on Dec 9 and New Moon occurring on Dec 16. Ursids max Dec 22-23Ursid activity lasts from approx Dec 16-25, with the radiant, at RA 14h28m, Dec +78, being highest late in the night and circumpolar for most northern hemisphere observers. High rates were recorded from this shower in 1945, 1982 ,1986, 2000, 2004 and 2006. It is suspected that other such peaks may have been missed due to lack of observations. With the Moon reaching First Quarter on Dec 24, observations before midnight will be hindered by moonlight, but darker skies will be available after midnightQuadrantids 2010 max Jan 03d18h UTChart. The Quadrantid radiant, lying at Dec +50, is circumpolar for observers north of latitude 40 N. The radiant is at its lowest altitude at around 20h local time and is highest at the end of the night. The maximum is usually rather narrow, with the predicted time for 2009 favouring observers at Asian Longitudes. However it should be noted that the 2009 peak was broader than usual with the ZHR being above 100 for nearly 12 hours. America and the Pacific region. The Moon will have been Full on Dec 31 and so will still be a problem from mid evening onwards by the night of maximum. |
|
Webmaster: Nick James |
The contents of this site, and communications between this site and its users, are protected by database right, copyright, confidentiality and the right not to be intercepted conferred by section 1(3) of the Regulation of Investigatory Powers Act 2000. The use of those contents and communications by Internet Service Providers or others to profile or classify users of this site for advertising or other purposes is strictly forbidden. |
