Last Updated:
2007 May 05 07:58 UTC
Source file:
forthcoming_meteors.txt
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Last Updated: |
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Contents
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Meteor Activity in 2007Edited by Tony MarkhamMoonlight conditions for observing the major meteor showers will be mostly favourable in 2007. The most active two showers - the Perseids and Geminids - peak within a few days of New Moon, whilst the Taurids and Leonids are also favourably timed and the Lyrids and Orionids are fairly well timed (if you can observe late in the night). As ever, there will be some showers unfavourably timed and in 2007 this is the case for the Eta Aquarids, Delta Aquarids-S, Alpha Capricornids and Ursids. Quadrantids max Jan 03d23h 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 Asia. Moonlight will be a serious problem for the 2007 peak, however, as the moon will be Full.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 2007 occurs on Feb 17, Mar 19 and Apr 17.Lyrids max Apr 22d21h UTChart. Lyrid activity can be seen from Apr 18-25. 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. The Moon will be at First Quarter on Apr 24 - on maximum night it will set at around 2h local time for observers at the latitude of the UK (somewhat earlier for observers further south) and so will have set by the time that the radiant reaches its greatest altitude.Eta Aquarids max May 4This shower produces higher ZHR values than the Lyrids. However, while easy to observe from the southern hemisphere and from the tropics, for observers in northern Europe it only produces low observed rates as dawn is approaching before the radiant reaches a reasonable altitude. The shower is unfavourably placed in 2007, with the Full Moon occurring on May 2. The radiant is 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 outburst were unexpected as the Earth now passes some distance from the orbit of the particles which produced the earlier outbursts. It will be worthwhile monitoring this shower’s activity in the years to come. Conditions are fairly unfavourable in 2007 with the above period occurring between First Quarter and Full Moon. However, it is worth noting that for observers at the latitude of the UK the moon will be low in the sky and so its 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. New Moon in 2007 occurs on July 14 with Full Moon occurring on July 30.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-N and -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. With Full Moon in 2007 occurring on July 30 and Last Quarter on Aug 5, conditions will be unfavourable for the Delta Aquarids-S, Piscis Australids and Alpha Capricornids but slightly better for the Iota Aquarids and Delta Aquarids-N.Perseids max Aug 13d02h 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 Full Moon of July 30 will make observations difficult for the early Perseids, but conditions will be much more favourable after Last Quarter on Aug 4 and the moon will be absent at Perseid maximum. 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.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 mis-identified 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). Some sources also list an Iota Aquarid-N maximum on Aug 20 and a second Kappa Cygnid maximum on Aug 26. New Moon in 2007 occurs on Aug 12 with Full Moon occurring on Aug 28.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). New Moon in 2007 occurs on Sep 11, with Full Moon occurring on Sep 26.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 07h-09h30m UT on 2007 Oct 6. This would favour observers in North America, but it would be also be worthwhile observers at other longitudes monitoring for activity given the vagueness of the details reported to date.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 2007. The moon will be a thin crescent in the morning sky and so will not hinder observations. The radiant, at RA 17h23m, Dec +57, lies near the head of Draco.OrionidsChart. Conditions for Orionid observing will be fairly favourable in 2007 - but only if you can observe late in the night after the moon has set (Full Moon occurs on Oct 26). 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 - and it sometimes brings surprises such as the unusually high rates seen during the night of 2006 Oct 21-22. The radiant position at maximum is RA 06h24m , Dec +15 (on the border of Gemini and Orion), rising around mid evening and at its greatest altitude late in the night. Thus the highest observed rates are likely to be seen late in the night. The radiant 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.TauridsChart. 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. The 2007 maximum is favourably timed, with New Moon occurring on Nov 9. However, some Taurid activity will also be visible during the Orionid watches of October and the Leonid watches of November. The radiants are highest at around the middle of the night.Leonids max Nov 18d 05hUTChart. Leonid activity last from Nov 14-20. The moon will be at First Quarter on Nov 17 and so will not hinder observations of the 2007 Leonids - given that the radiant doesn't rise until late evening. We have now encountered all of the significant Leonid filaments and so for the next two decades we will only be seeing the Leonid background levels. However observations are still required to monitor how this varies between returns of the parent comet.Geminids max Dec 14d11h UTChart. Moonlight conditions are very favourable for the Geminids in 2007 with New Moon occurring on Dec 9. Although the Geminids have been 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.Ursids max Dec 22-23Moonlight conditions will be unfavourable for the Ursids in 2007 with Full Moon occurring on Dec 24. Ursid 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.Quadrantids 2008 max Jan 04d05h 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 western Europe. The moon will be a thin crescent in the morning sky and so will not be a serious problem for the 2008 peak. |
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