IMO Meteor Shower Calendar 2009

compiled by Alastair McBeath. Based on information in IMO Monograph No. 2: Handbook for Visual Meteor Observers, edited by Jürgen Rendtel, Rainer Arlt and Alastair McBeath, IMO, 1995, as amended by the commentaries in WGN 34:3 (June 2006), pp. 71-84, with subsequent corrections, plus additional material extracted from reliable data analyses produced since. Particular thanks are due to Rainer Arlt, David Asher, Jeff Brower, David Entwistle, Esko Lyytinen and Jérémie Vaubaillon for valuable discussions in respect of several events in 2009.

Introduction

Welcome to the 2009 International Meteor Organization (IMO) Meteor Shower Calendar. Of the more active annual showers, the Quadrantids, Lyrids, η- and Southern δ-Aquariids, Orionids, Leonids and Geminids are best placed with regards the Moon, along with the occasionally stronger Ursids in December. Of greatest potential interest for what they may produce are the η-Aquariids and Orionids (which should be near their theoretical 12-year ZHR peaks in 2009, the Orionids having already produced unexpectedly strong activity in both 2006 and 2007, albeit apparently not from this cause), the moonlit Perseids, which may show an additional maximum again this year, and the Leonids, which could yield ZHRs in the 100+ category, maybe (if we are very fortunate) bordering on near-storm levels again! For radio observers, and hopeful daylight fireball enthusiasts, there is the chance of another Taurid 'swarm' return in June-July. There are minor showers to be monitored as well, and ideally, meteor observing should be carried out throughout the year to check on all the established sources, and for any new ones. We appreciate this is impractical for most people, so the Shower Calendar has been helping to highlight times when a particular effort might most usefully be employed since 1991.

The heart of the Calendar is the Working List of Visual Meteor Showers, Table 5, which had its most recent overhaul by IMO analysts in 2006, to help it remain the single most accurate listing available anywhere today for naked-eye meteor observing. Of course, for all its accuracy, it is a Working List, so is continually subject to further checks and corrections, based on the best data we have, so it is always as well to check the information here fully, before going out to observe (and please notify us if you find any anomalies!).

Apart from the visually-observable showers, there are many others weakly active throughout the year which only still-imaging, video, radar or telescopic observations can separate from the omnipresent background sporadics, as well as showers with radiants too near the Sun to be observed by the various optical methods, which can be detected only by forward-scatter radio or radar observations. Some of these showers are given in Table 7, the Working List of Daytime Radio Meteor Showers. The IMO's aims are to encourage, collect, analyze, and publish combined meteor data obtained from sites all over the globe, to help better our understanding of the meteor activity detectable from the Earth's surface. Thus, we encourage these more specialist forms of observing too, so all meteor workers, wherever you are and whatever methods you use to record meteors, should follow the standard IMO observing guidelines when compiling your information, and submit those data promptly to the appropriate Commission for analysis (contact details are at the end of the Calendar). Thanks to the efforts of the many IMO observers worldwide since 1988 that have done this, we have been able to achieve as much as we have to date, including keeping the shower listings vibrant. This is not a matter for complacency however, since it is solely by the continued support of many people across the planet that our steps towards constructing a better and more complete picture of the near-Earth meteoroid flux can proceed.

Although timing predictions are included below on all the more active night-time and daytime shower maxima, as reliably as possible, it is essential to understand that in many cases, such maxima are not known more precisely than to the nearest 1° of solar longitude (even less accurately for the daytime radio showers, which have received little regular attention until quite recently). In addition, variations in individual showers from year to year mean past returns are only a guide as to when even major shower peaks can be expected. The information given here may be updated after the Calendar is published, so be sure to watch for alerts on the Internet (including on IMO-News) and in WGN, the IMO's bimonthly journal. Some showers are known to show particle mass-sorting within their meteoroid streams, so the radar, radio, still-imaging, telescopic, video and visual meteor maxima may occur at different times from one another, and not necessarily just in those showers. The majority of data available are for visual shower maxima, so this must be borne in mind when employing other observing techniques.

However and whenever you are able to observe, we wish you all a most successful year's work and very much look forward to receiving your data. Clear skies!

Antihelion Source

The Antihelion Source (ANT) is a large, roughly oval area with a size of 30° in right ascension and 15° in declination, centred about 12° east of the solar opposition point on the ecliptic, hence its name. It is not a true shower at all, but is rather a region of sky in which a number of variably, if weakly, active minor showers have their radiants. Until 2006, attempts were made to define specific showers within this complex, but this often proved very difficult for visual observers to achieve. IMO video results from the last decade have shown why, because even instrumentally, it was impossible to usefully define distinct radiants for many of the showers here! Consequently, we currently believe it is best for observers to simply identify meteors from these showers as coming from the ANT alone. At present, we think the July-August α-Capricornids (CAP), and particularly the Southern δ-Aquariids (SDA; because their stream parameters are rather different from the average ANT orbits), should remain discretely observable visually from the ANT, so they have been retained in the Working List, but time and plenty of observations will tell, as ever. Later in the year, the strength of the twin Taurid showers (STA and NTA) means the ANT should be considered inactive while the Taurids are underway, from late September to late November. To assist observers, a set of charts showing the location for the ANT and any other nearby shower radiants is included here, to compliment the numerical positions of Table 6, while comments on the ANT's location and likely activity are given in the quarterly summary notes.

January to March

First quarter Moon favours the northern-hemisphere Quadrantids in early January, but the probable southern-hemisphere α-Centaurid peak, due around 23h UT on February 7, is too close to full Moon on February 9. Mid-March brings an equally poor minor γ-Normid return for similarly southern places, likely at maximum sometime between March 10-17, perhaps most plausibly around March 13. The Antihelion Source's radiant centre starts January in south-east Gemini, and crosses Cancer during much of the month, before passing into southern Leo for most of February. It then slips through southern Virgo during March. Likely ANT ZHRs will be < 2, though IMO analyses suggest there may be an ill-defined minor peak with ZHRs ~ 2 to 3 around λo ~ 286°-293° (January 6 to 13 in 2009, ruined by full Moon, if so), and ZHRs could be ~ 3 for most of March. The late January to early February spell, during which several new, swift-meteor minor showers radiating from the Coma-Leo-Virgo area have been suggested in some recent years, enjoys a new Moon for its potential core period, January 20-27. Theoretical approximate timings (rounded to the nearest hour) for the daytime radio shower maxima this quarter are: Capricornids/Sagittariids - February 1, 9h UT; and χ-Capricornids - February 13, 10h UT. Recent radio results suggest the Cap/Sgr maximum may variably fall sometime between February 1-4 however, while activity near the expected χ-Capricornid peak has tended to be slight and up to a day late. Both showers have radiants < 10°-15° west of the Sun at maximum, so cannot be regarded as visual targets even from the southern hemisphere.

Quadrantids (QUA)

Active: January 1-5
Maximum: January 3 12h50m UT (λo = 283°16)
ZHR = 120 (can vary ~ 60-200)
Radiant: α = 230° δ = +49°
Radiant drift: see Table 6
v = 41 km/s; r = 2.1 at maximum (but variable)
TFC: α = 242° δ = +75° and α = 198° δ = +40° (β > 40° N)
IFC: before 0h local time α = 150° δ = +70°
∞ after 0h local time α = 180° δ = +40° and α = 240° δ = +70° (β > 40° N)

The waxing crescent Moon will set near local midnight for the maximum of the Quadrantids at northern hemisphere sites, from many of which, the shower's radiant is circumpolar, in northern Boötes. As this area attains a useful elevation only after local midnight, rising higher in the sky towards morning twilight, this is excellent news. However, the expected peak's timing falls poorly for land-based observers, except for those in the extreme western areas of North America, on islands in the North Pacific Ocean, and the extreme east of Russia. An interesting challenge is to try spotting the occasional long-pathed shower member from the southern hemisphere around dawn, but sensible Quadrantid watching cannot be carried out from such places.

The maximum timing above is based on the best-observed return of the shower ever analysed, from IMO 1992 data, confirmed by radio results in most years since 1996. The peak itself is normally short-lived, and can be easily missed in just a few hours of poor northern-winter weather, which may be why the ZHR level apparently fluctuates from year to year, but some genuine variability is probably present too. For instance, visual ZHRs in preliminary results from 2008 persisted for more than two hours at close to their best, with the maximum itself centred around three to four hours later than anticipated. An added level of complexity comes from the fact that mass-sorting of particles across the meteoroid stream may make fainter objects (radio and telescopic meteors) reach maximum up to 14 hours before the brighter (visual and photographic) ones, so observers should be alert throughout the shower. A few, but apparently not all, years since 2000 seem to have produced a, primarily radio, maximum following the main visual one by some 9-12 hours. Visual confirmation of any repeat near this time in 2009 would fall ideally for sites from Europe east to central Asia. Oddly, in 2008, there seemed to be two possible radio Quadrantid peaks, but the first was apparently about six hours before the visual one, during an apparent rates-plateau ahead of the main maximum in the visual data.

Past observations have suggested the QUA radiant is diffuse away from the maximum, contracting notably during the peak itself, although this may be a result of the very low activity outside the hours near maximum. Still-imaging and video observations from January 1-5 would be particularly welcomed by those investigating this topic, using the IFCs and TFCs given above, along with telescopic and visual plotting results.

April to June

Meteor activity picks up towards the April-May boundary, with excellently moonless shower peaks in late April from the Lyrids and π-Puppids, and even the η-Aquariids in early May survive the waxing gibbous Moon. The minor η-Lyrids will likely pass unobserved however, with their low-activity maximum on May 9 coincident with full Moon. Later in May and throughout June, most of the meteor action switches to the day sky, with six shower maxima expected during this time. Although occasional meteors from the o-Cetids and Arietids have been claimed as seen from tropical and southern hemisphere sites visually in past years, ZHRs cannot be sensibly calculated from such observations. For radio observers, the theoretical UT peaks for these showers are as follows: April Piscids - April 20, 9h; δ-Piscids - April 24, 9h; ε-Arietids - May 9, 8h; May Arietids - May 16, 9h; o-Cetids - May 20, 8h; Arietids - June 7, 11h; ζ-Perseids - June 9, 11h; β-Taurids - June 28, 10h. Signs of most of these were found in radio data from 1994-2007, though some are difficult to define individually because of their proximity to other radiants. There seems to be a modest recurring peak around April 24, perhaps due to combined rates from the first three showers listed here, for instance, while the Arietid and ζ-Perseid maxima tend to blend into one another, producing a strong radio signature for several days in early to mid June. There are indications these two June shower maxima now each occur up to a day later than indicated above.

The Antihelion Source should be relatively strong, with ZHRs of 3 to 4 found in recent investigations through till mid April, and again around late April to early May, late May to early June, and late June to early July. At other times, the ZHR seems to be below ~ 2 to 3. The radiant area drifts from south-east Virgo through Libra in April, then across the northern part of Scorpius to southern Ophiuchus in May, and on into Sagittarius for much of June. For northern observers, circumstances for checking on any potential June Lyrids (not currently on the Working List, but possibly producing some weak activity, if at all, around June 16) are not too favourable this year, with last quarter Moon rising around midnight. Conditions are rather better for possible June Boötid hunting.

Taurid 'swarm' return: Work by David Asher has suggested the possibility of another return of the Taurid meteoroid 'swarm' during June 2009. If so, it may be detectable as an increased radio meteor flux during the ζ-Perseids or the β-Taurids, both of which are probably associated with the Taurid Complex of meteor showers, asteroids and comets. Each of the last three predicted night-time 'swarm' events during the October-November Taurids, in 1995, 1998 and 2005 produced noticeably different activity to normal. In 2005, and most impressively of the three, this included increased Taurid ZHRs and a lot of shower fireballs from late October to mid-November. Another night-time 'swarm' return was due in late 2008, still to come when this Calendar text was prepared. However, previous theoretical daytime 'swarm' returns in 1995, 1999 and 2002 have proven elusive, with nothing very remarkable found in the June-July radio results for any of those years that might be definite signs of such a return. The encounter geometry in 2009 June is expected to be similar to that in 2005 October-November, so any repeat of comparable activity may give the best chance of such a daytime-sky recovery, if it happens. The most likely time for anything to be detected is probably about 5- days before the β-Taurid peak, thus around June 20-23, but its potential timing and strength are unknown. There is also the chance that if an increased fireball flux takes place, there may be some daylight fireballs reported visually, though of course these cannot be deliberately watched for.

Lyrids (LYR)

Active: April 16-25
Maximum: April 22 11h UT (λo = 32°32 (but may vary - see text))
ZHR = 18 (can be variable - up to 90)
Radiant: α = 271° δ = +34°
Radiant drift: see Table 6
v = 49 km/s; r = 2.1
TFC: α = 262° δ = +16° and α = 282° δ = +19° (β > 10° S)

The λo = 32°32 timing given above is the 'ideal' maximum found in the most detailed examination of the Lyrids in modern times, published in 2001 by Audrius Dubietis and Rainer Arlt, drawing on IMO results from 1988-2000. However, the maximum time was found to be variable from year to year between λo = 32°0-32°45 (equivalent to 2009 April 22, 3h to 14h UT). Activity was discovered to be variable too. A peak at the ideal time produced the highest ZHRs, ~ 23, while the further the peak happened from this, the lower the ZHRs were, down to ~ 14. (The last very high maximum occurred outside the examined interval, in 1982 over the USA, when a short-lived ZHR of 90 was recorded.) The mean peak ZHR was 18 over the thirteen years examined. While generally thought of as having a short, quite sharp, maximum, this latest work revealed the shower's peak length was inconstant too. Using the interval that ZHRs were above half the maximum amount, the Full-Width-Half-Maximum time, a variation of from 14.8 hours (in 1993) to 61.7 hours (in 2000) was detected, with a mean value of 32.1 hours. The very best rates are normally achieved for just a few hours however. One other aspect of the analysis confirmed data from earlier in the 20th century, that occasionally, as their highest rates occurred, the Lyrids produced a short-lived increase in fainter meteors. Overall, the unpredictability of the shower in any given year always makes the Lyrids worth watching, since we cannot say when the next unusual return may take place.

Lyrids are best viewed from the northern hemisphere, but they are visible from many sites north and south of the equator, and the shower is suitable for all forms of observation. As its radiant rises during the night, watches can be usefully carried out from about 22h30m local time onwards from mid-northern sites, but only from well after midnight from the mid-southern hemisphere. The waning crescent Moon will rise too late in the night in the northern hemisphere to cause any problems, and will be just a minor distraction further south on April 22. If the ideal maximum time recurs, it should be best seen from sites across the central to eastern Pacific Ocean, and the extreme west of North America, but other maximum times are perfectly possible, as noted above.

π-Puppids (PPU)

Active: April 15-28
Maximum: April 23 16h UT (λo = 33°5)
ZHR = periodic - up to around 40
Radiant: α = 110° δ = -45°
Radiant drift: see Table 6
v = 18 km/s; r = 2.0
TFC: α = 135° δ = -55° and α = 105° δ = -25° (β < 20° N)

Activity has only been detected from this source since 1972, with notable, short-lived, shower maxima of around 40 meteors per hour in 1977 and 1982, both years when its parent comet, 26P/Grigg-Skjellerup was at perihelion. Before 1982, little activity had been seen at other times, but in 1983, a ZHR of ~ 13 was reported, perhaps suggesting material has begun to spread further along the comet's orbit, as theory predicts. Comet Grigg-Skjellerup's most recent perihelion in 2008 March produced nothing meteorically significant that April, but lunar circumstances in 2008 were poor, and faint-meteor activity (which was predicted as likely in advance) could have been missed. There were no predictions for activity in force for 2009 when this Calendar was prepared. The π-Puppids are best seen from the southern hemisphere, with useful observations mainly practical there before midnight, as the radiant is very low to setting after 1h local time. April's new Moon on the 25th creates perfect viewing circumstances this year. Covering whatever happens is important in all years, even if that is to report no obvious activity, as past datasets on the shower have typically been very patchy. So far, visual and radio data have been collected on the shower, but the slow, sometimes bright nature of the meteors makes them ideal subjects for imaging too. No telescopic or video data have been reported in any detail as yet.

η-Aquariids (ETA)

Active: April 19-May 28
Maximum: May 6 0h UT (λo = 45°5
ZHR = 85 (periodically variable - ~ 40-85)
Radiant: α = 338° δ = -01°
Radiant drift: see Table 6
v = 66 km/s; r = 2.4
TFC: α = 319° δ = +10° and α = 321° δ = -23° (β < 20° S)

A fine, rich shower associated with Comet 1P/Halley, like the Orionids of October, but one visible for only a few hours before dawn, essentially from tropical and southern hemisphere sites. Some useful results have come even from sites around 40°N latitude in recent years however, and occasional meteors have been reported from further north, but the shower would benefit from increased observer activity generally. The fast and often bright meteors make the wait for radiant-rise worthwhile, and many events leave glowing persistent trains after them. While the radiant is still low, η-Aquariids tend to have very long paths, which can mean observers underestimate the angular speeds of the meteors, so extra care is needed when making such reports.

A relatively broad maximum, sometimes with a variable number of submaxima, usually occurs in early May. Fresh IMO analyses in recent years, based on data collected between 1984-2001, have shown that ZHRs are generally above 30 between about May 3-10, and that the peak rates appear to be variable on a roughly 12-year timescale. The next highest rates should fall towards 2008-2010, if this Jupiter-influenced cycle is borne-out, thus ZHRs could be around their very best in 2009, according to this idea. However, activity in 2007 seemed unexpectedly weaker than normal (peak ZHRs maybe only ~ 50), which combined with the unexpectedly strong Orionid returns in October 2006 and 2007, add an extra degree of uncertainty over what may happen from the η-Aquariids this year. The waxing gibbous Moon on May 6 will set in time to still leave most of the best-visible interval viable for visual watchers well south of the equator, at least. All forms of observing can be used to study the shower, with radio work allowing activity to be followed even from many northern latitude sites throughout the daylight morning hours. The radiant culminates at about 8h local time.

June Boötids (JBO)

Active: June 22-July 2
Maximum: June 27 08h30m UT (λo = 95°7
ZHR = variable - 0-100+
Radiant: α = 224° δ = +48°
Radiant drift: see Table 6
v = 18 km/s; r = 2.2
TFC: α = 156° δ = +64° and α = 289° δ = +67° (β = 25°-60° N)

This source was reinstated on the Working List after its unexpected return of 1998, when ZHRs of 50-100+ were visible for more than half a day. Another outburst of similar length, but with ZHRs of ~ 20-50 was observed on 2004 June 23, a date before definite activity had previously been recorded from this shower. Consequently, the shower's start date was altered to try to ensure future activity so early is caught, and we encourage all observers to routinely monitor throughout the expected activity period, in case of fresh outbursts. Prior to 1998, only three more probable returns had been detected, in 1916, 1921 and 1927, though that in 1921 was very uncertainly recorded. With no significant reports between 1928 and 1997, it seemed likely these meteoroids no longer encountered Earth. The dynamics of the stream were poorly understood, although recent theoretical modelling has improved our comprehension. The shower's parent, Comet 7P/Pons-Winnecke, has an orbit that now lies around 0.24 astronomical units outside the Earth's at its closest approach. Its most recent perihelion passage was in 2008 September. Clearly, the 1998 and 2004 returns resulted from material shed by the comet in the past which now lies on slightly different orbits to the comet itself. Dust trails laid down at various perihelion returns during the 19th century seem to have been responsible for the last two main outbursts. There were no predictions in force for possible activity in 2009 at the time of writing, but conditions for checking are very favourable from the mid-northern latitudes where the radiant is best seen, with an early-setting waxing crescent Moon. The prolonged - in some places continuous - mid-northern twilight means the summer nights are short anyway. The radiant is usefully accessible virtually all night, and all observing techniques can be employed.

July to September

The Antihelion Source is the chief focus for visual attention for most of July, as its radiant area moves steadily through eastern Sagittarius, then across northern Capricornus into south-west Aquarius. Results suggest the Source may not be especially recognisable after the first few days however, as ZHRs for most of the month seem < 2, and for a time in mid-month even < 1! Activity appears to improve somewhat, with ZHRs ~ 2 to 3, by late July and through the first half of August. This level of ZHRs may make it more practical to still identify the reasonably moonless α-Capricornid maximum, despite that radiant's overlap with the Antihelion Source's. The Southern δ-Aquariids are strong enough, and the Piscis Austrinids have a radiant probably distant enough from the ANT area, that both should still be separable from it, particularly from the southern hemisphere. By the best from the major, badly moonlit, Perseids, and the almost Moon-free κ-Cygnid peak, ANT ZHRs will likely have dropped back below 2 again, as the radiant tracks on through Aquarius, and into western Pisces by the α-Aurigid maximum on the August-September boundary. The minor September Perseids lose out to the waning gibbous Moon for their likely maximum around September 9, but part of the probable very weak δ-Aurigid peak later in the month should be clear enough of the Moon to observe.

For most of September, ANT rates continue from their radiant in Pisces, albeit with ZHRs probably no better than 2-3, but remember that from September 25, Antihelion meteors are no longer to be recorded as such, as both Taurid showers take over the near-ecliptic shower baton until late November. For daylight radio observers, the interest of May-June has waned, but there remain the visually-impossible γ-Leonids (peak due near August 25, 10h UT, albeit not found in recent radio results), and a tricky visual shower, the Sextantids. Their maximum is expected on September 27, around 10h UT, but may possibly occur a day earlier. In 1999 a strong return was detected at λo ~ 186° equivalent to 2009 September 29, while in 2002, the September 27 peak was not found, but one around September 29-30 was! It seems plausible that several minor maxima in early October may also be due to this radio shower. The waxing gibbous Moon creates no additional difficulties for visual observers hoping to catch some Sextantids in the pre-dawn of late September, though radiant-rise is less than an hour before sunrise in either hemisphere.

Perseids: Although the major northern hemisphere Perseids are badly affected by the last quarter Moon near their best this year, there is the possibility they may produce more than one peak again, perhaps also with somewhat increased rates. The usual maximum is due around August 12, 17h30m-20h00m UT (λo = 140°0-140°1), but Esko Lyytinen suggests we may encounter the 1610 Perseid trail earlier on August 12, around 9h00m UT (λo = 139°661). This could produce activity additional to the normal Perseid ZHRs then of a few tens, maybe up to a hundred, probably with a fairly normal magnitude distribution, or perhaps marginally brighter. He further suggests that rates overall could be enhanced above usual by the relative proximity of the annual stream's core, most likely at other times on August 12 ahead of the normal peak. The 19th century trail should pass roughly 0.003 astronomical units inside the Earth's orbit at λo = 139°499, so around 5h UT on August 12, though it may add less than 10 to the ZHR at that point. Naturally, information to verify what takes place will be very valuable despite the Moon, so visual observers are encouraged to try to follow as much of what happens over the possible Perseid maxima as practical.

Piscis Austrinids (PAU)

Active: July 15-August 10
Maximum: July 28 (λo = 125°)
ZHR = 5
Radiant: α = 341° δ = -30°
Radiant drift: see Table 6
v = 35 km/s; r = 3.2
TFC: α = 255° to 000° δ = 00° to +15°
choose pairs separated by about 30° in α (β < 30° N)

Very little information has been collected on the Piscis Austrinids in recent decades, so the details on the shower are not well confirmed, and it seems possible the ZHR may be a little optimistic. However, that impression may be due simply to the large amount of northern hemisphere summer data, and the almost complete lack of southern hemisphere winter results, on it. The shower seems to be rich in faint meteors, rather like the nearby ANT and SDA, so telescopic work is advisable to try to establish more about it. First quarter Moon for the probable maximum will set between 22h-00h (its setting time is progressively later for places further south).

Southern δ-Aquariids (SDA)

Active: July 12-August 19
Maximum: July 28 (λo = 125°)
ZHR = 20
Radiant: α = 339° δ = -16°
Radiant drift: see Table 6
v = 41 km/s; r = 3.2
TFC: α = 255° to 0° δ = 0° to +15°
choose pairs separated by about 30° in α (β < 40° N)

Like the PAU and ANT, SDA meteors are often faint, thus are suitable targets for telescopic observing, although enough brighter members exist to make visual and imaging observations worth the effort too, primarily from more southerly sites. Radio work can pick up the SDA as well, and indeed the shower has sometimes given a surprisingly strong radio signature. Careful visual plotting is advised, to help with accurate shower association. The SDA/PAU/ANT/CAP radiants are well above the horizon for much of the night, and the SDA enjoys identical dark-sky conditions in the second half of the nights near its maximum to the PAU. Its peak may not be quite so sharp as the single date here might imply, with perhaps similar ZHRs from July 28-30. Its rates have been suspected of some variability at times too, though not in the more recent investigations.

α-Capricornids (CAP)

Active: July 3-August 15
Maximum: July 30 (λo = 127°)
ZHR = 4
Radiant: α = 307° δ = -10°
Radiant drift: see Table 6
v = 23 km/s; r = 2.5
TFC: α = 255° to 0° δ = 0° to +15°
choose pairs separated by about 30° in α (β < 40° N)
IFC: α = 300° δ = +10° (β > 45° N)
α = 320° δ = -05° (β=0° to 45° N)
α = 300° δ = -25° (β < 0°)

The CAP and SDA were both definitely detected visually in former years, standing out against the much weaker other radiants supposed active in Capricornus-Aquarius then. Whether the CAP can still be detected separately from the new ANT radiant area remains to be discovered, as its radiant now partly overlaps that of the large ANT oval region. The slightly slower speed of the α-Capricornids compared to the ANT may help distinguish them from the ecliptical background.} In their favour, CAP meteors are noted for being bright, at times even of fireball-class, 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 CAP ZHRs to ~ 10 was noted in 1995 by European IMO observers. More recent results suggest the maximum may continue for an extra day, so perhaps from July 30-31 this year. The waxing gibbous Moon sets somewhat later for this interval than for the PAU and SDA, even so, between roughly 23h-3h (again, later moonsets occur at more southerly latitudes).

κ-Cygnids (KCG)

Active: August 3-25
Maximum: August 17 (λo = 145°)
ZHR = 3
Radiant: α = 286° δ = +59°
Radiant drift: see Table 6
v = 25 km/s; r = 3.0
IFC: α = 330° δ = +60° and α = 300° δ = +30° (β > 20° N)

The waning crescent Moon creates no problems for viewing the expected κ-Cygnid peak this year from northern hemisphere sites, where the shower is chiefly accessible. Its r-value suggests telescopic and video observers may benefit from the shower's presence, but visual and photographic workers should note that occasional slow fireballs from this source have been reported too. The almost stationary radiant results from its close proximity to the ecliptic north pole in Draco. There has been some suggestion of a variation in its activity at times, perhaps coupled with a periodicity in fireball sightings, but more data are needed on a shower that is often ignored in favour of the major Perseids during August.

Aurigid Showers

α-Aurigids (AUR)

Active: August 25-September 8
Maximum: September 1 01h UT (λo = 158°6)
ZHR = 7
Radiant: α = 84° δ = +42°
Radiant drift: see Table 6
v = 66 km/s; r = 2.6
TFC: α = 052° δ = +60°; α = 043° δ = +39° and
α = 023° δ = +41° (β > 10° S)

δ-Aurigids (DAU)

Active: September 18-October 10
Maximum: September 29 (λo = 186°) but see text
ZHR = 3
Radiant: α = 82° δ = +49°
Radiant drift: see Table 6
v = 64 km/s; r = 2.9
TFC: As AUR

Along with the September Perseids (SPE), these essentially northern hemisphere showers appear to be part of a series of poorly-observed sources with radiants around Aries, Perseus, Cassiopeia and Auriga, active from late August into October. IMO investigations using data collected since 1986 have suggested there are at least three showers which repeat annually, of which the AUR are the marginally stronger. Telescopic data to examine all the radiants in this region of sky - and possibly observe the telescopic β-Cassiopeids simultaneously - would be especially valuable, but still-imaging, video records and visual plotting would be welcomed too.

The AUR have produced short, unexpected outbursts at times, with EZHRs of ~ 30-40 recorded in 1935, 1986 and 1994, although they have not been monitored regularly until very recently, so other events may have been missed. Only three watchers in total covered the 1986 and 1994 outbursts, for instance! While badly moonlit, the first predicted outburst happened roughly as expected in 2007, producing short-lived EZHRs of ~ 130 for western North America, with many bright meteors. Radio data suggested there was a 'tail' to that event where more faint meteors continued for maybe an hour after the strongest peak, but visual observers could not confirm this, pobably due to the moonlit sky. Both Aurigid radiants reach useful elevations after 23h-0h local time, and this year conditions are reasonably good for the AUR peak, with the waxing gibbous Moon setting between midnight and 2h on August 31-September 1. No predictions for stronger activity had been made when this text was written, however.

The DAU name has recently been adopted for the weaker segment of what may be a single shower, as its radiant and activity follow along directly from those of the September Perseids. At present, the showers should be treated as distinct in your observations. The DAU seem to give a weak and very ill-defined maximum between roughly λo = 181°-191° (2009 September 24 to October 4). September 29 is simply the approximate middle of this peak interval, with a waxing gibbous Moon this year that will set before local midnight north of the equator. The later part of this possible maximum spell will see increasing moonlight problems as full Moon approaches on October 4.

October to December

An excellent final quarter to the year beckons, with maxima from the all more active showers splendidly moonless. Only three less active shower peaks are lost to the bright Moon, those of the Southern Taurids, σ-Hydrids (December 12) and Coma Berenicids (probably around December 29, but see the notes below). The period near the possible Puppid-Velid early-December maximum/reference date, December 7, is also badly Moon-affected. The ANT starts the quarter effectively inactive in favour of the Taurids, but as the Taurids fade away, we should be able to again distinguish them from the sporadics as the sole ecliptical background from November 26, with a radiant centre position in eastern Taurus. During December, this centre tracks across southern Gemini, and although analyses indicate its likely ZHRs are < 2 for most of this time, some of this apparent inactivity may be due to the strength of the Geminids very close-by to the north during part of December, plus also the minor Monocerotids a little way to its south simultaneously.

October 5/6 meteors: Short-lived video outbursts were recorded in 2005 and 2006 by European observers, with activity from a north-circumpolar radiant near the 'tail' of Draco, around α ~ 165° δ ~ +78° on October 5/6. The 2005 event (only) was recorded very weakly by radio, but no visual results confirmed either occurrence, and no recurrence was reported in 2007. The 2008 repeat time was still to come when this was written. As the 2005/2006 events happened between λo ~ 192°55-192°64, this would be equivalent to 2009 October 5, 19h20m-21h30m UT, poorly timed for observing thanks to the bright Moon, full on October 4. The meteors showed an atmospheric velocity of ~ 45-50 km/s. If the active interval keeps to the same time, it would be best observed by video from Europe east across all of Asia.

Coma Berenicids (COM): As noted in the 2008 Shower Calendar, IMO single-station video data prepared just be