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IMO INFO(2-19) 1
International Meteor Organization
2020 Meteor Shower Calendar
edited by J¨urgen Rendtel 1
1 Introduction
This is the thirtieth edition of the International Meteor Organization (IMO) Meteor Shower
Calendar, a series which was started by Alastair McBeath. Over all the years, we want to draw
the attention of observers to both regularly returning meteor showers and to events which may be
possible according to model calculations. We may experience additional peaks and/or enhanced
rates but also the observational evidence of no rate or density enhancement. The position of
peaks constitutes further important information. All data may help to improve our knowledge
about the numerous effects occurring between the meteoroid release from their parent object and
the currently observable structure of the related streams. Hopefully, the Calendar continues to
be a useful tool to plan your meteor observing activities during periods of high rates or periods
of specific interest for projects or open issues which need good coverage and attention.
Video meteor camera networks are collecting data throughout the year. Nevertheless, visual
observations comprise an important data sample for many showers. Because visual observers
are more affected by moonlit skies than video cameras, we consider the moonlight circumstances
when describing the visibility of meteor showers. For the three strongest annual shower peaks
in 2020 we find the first quarter Moon for the Quadrantids, a waning crescent Moon for the
Perseids and new Moon for the Geminids. Conditions for the maxima of other well-known
showers are good: the Lyrids are centred around new Moon, the Draconids occur close to the
last quarter Moon and the Orionids as well as the Leonids see a crescent only in the evenings.
Other maximum periods are more affected by moonlight: the η-Aquariids peak shortly before
full Moon, the Southern δ-Aquariids see a waxing gibbous Moon and the Ursids reach their
maximum close to first quarter Moon.
The heart of the Calendar is the Working List of Visual Meteor Showers (Table 5) which is
continuously updated so that it is the single most accurate listing available anywhere today
for visual meteor observing. Nevertheless, it is a Working List which is subject to further
modifications, based on the best data we had at the time the Calendar was written. Observers
should always check for later changes noted in the IMO’s journal WGN or on the IMO website.
Vice versa, we are always interested to receive information whenever you find any anomalies! To
allow for better correlation with other meteor shower data sources, we give the complete shower
designation including the codes taken from IAU’s Meteor Data Center listings.
1Based on information in the Meteor Observers Workbook 2014, edited by J¨urgen Rendtel (referred to as ‘WB’
in the Calendar), and “A Comprehensive List of Meteor Showers Obtained from 10 Years of Observations with
the IMO Video Meteor Network” by Sirko Molau and J¨urgen Rendtel (referred to as ‘VID’ in the Calendar), as
amended by subsequent discussions and additional material extracted from data analyses produced since. Partic-
ular thanks are due to Peter Jenniskens, Esko Lyytinen, Mikhail Maslov, Mikiya Sato and J´er´emie Vaubaillon for
new information and comments in respect of events in 2020 (see also the References in section 8). Koen Miskotte
summarized information for the SDA and CAP activity in late July. Last but not least thanks to David Asher,
Robert Lunsford, Alastair McBeath and Sirko Molau for carefully checking the contents.
2IMO INFO(2-19)
The available predictions for 2020 do not include any spectacular outburst, but some very
interesting encounters which are relevant for future predictions which are described in the text
and listed in Table 6a. Since there is always a possibility of completely unexpected events,
ideally meteor observing should be performed throughout the year. This way we can improve
the data for established meteoroid streams covering their entire activity periods. Combining data
obtained with different techniques improve the reliability of derived quantities and is helpful for
calibrating purposes.
Video meteor observations allow us to detect weak sources. An increasing number of confirmed
radiants provides us with more possibilities to establish relations between meteoroid streams
and their parent objects. Some of the sources may produce only single events but no annual
recurring showers, such as, for example, the June Bootids and the October Draconids.
Observing techniques which allow the collection of useful shower data include visual, video and
still-imaging along with radar and radio forward scatter methods. Visual and video data allow
rate and flux density calculations as well as determination of the particle size distribution in
terms of the population index ror the mass index s. Multi-station camera setups provide us
with orbital data, essential for meteoroid-stream investigations. Showers with radiants too near
the Sun for observing by the various optical methods can be detected by forward-scatter radio
or back-scatter radar observations – although attempts with optical observations can be useful
too. Some of the showers are listed in Table 7, the Working List of Daytime Meteor Showers.
The IMO’s aims are to encourage, collect, analyze, and publish combined meteor data obtained
from sites all over the globe, to improve our understanding of the meteor activity detectable
from the Earth’s surface. For best effects, it is recommended that all observers should follow
the standard IMO observing guidelines when compiling information, and submit those data
promptly to the appropriate Commission for analysis (contact details are at the end of the
Calendar). Many analyses try to combine data obtained by more than one method, extending
the ranges and coverage but also to calibrate results from different techniques. 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 attempts to construct a better and more complete picture of the
near-Earth meteoroid flux can proceed.
Timing predictions are included below on all the more active night-time and daytime shower
maxima as reliably as possible. However, it is essential to understand that in many cases, such
maxima are not known more precisely than to the nearest degree of solar longitude. 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. As noted already, the information given here may be
updated and added-to after the Calendar has been published. Some showers are known to show
particle mass-sorting within their meteoroid streams, so the radar, radio, still-imaging, 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, whose input is possible via the online form
on the IMO’s website www.imo.net. Clear skies!
IMO INFO(2-19) 3
2 Antihelion Source
The Antihelion Source (ANT) is a large, roughly oval area of about 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 (hence it has no IAU shower number), 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 have shown why, because
even instrumentally, it was impossible to define distinct and constantly observable radiants for
many of the showers here! Thus we recommend observers simply to identify meteors from these
streams as coming from the ANT alone. Apart from this, we have been able to retain the July-
August α-Capricornids, and particularly the Southern δ-Aquariids as apparently distinguishable
showers separate from the ANT. Later in the year, the Taurid showers dominate the activity
from the Antihelion region meaning the ANT should be considered inactive while the Taurids are
underway, from early September to early December. To assist observers, a set of charts showing
the location for the ANT and any other nearby shower radiants is included here, to complement
the numerical positions of Table 6, while comments on the ANT’s location and likely activity
are given in the quarterly summary notes.
3 January to March
The year starts with the Quadrantid (010 QUA) peak for the northern hemisphere observers
on January 4 just after the first quarter Moon. Conditions to collect data of the weak γUrsae
Minorids (404 GUM) around January 10 are very poor. The December Leonis Minorids
(032 DLM) which can be traced until early February are well observable during the two moon-
less periods in early and again in late January. The southern hemisphere’s α-Centaurids (102
ACE) around February 8 are badly affected by moonlight. A part of the γ-Normids (118
GNO) of March can be traced well in darker skies.
30
Jan 10
20
30
Feb 10
20
Mar 10
20
ANT (Jan–Mar)
The ANT’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 shifts through
southern Virgo during March. Probable ANT ZHRs will be <2, although IMO analyses of
visual data have suggested there may be an ill-defined minor peak with ZHRs ≈2 to 3 around
4IMO INFO(2-19)
λ⊙≈286◦–293◦(2020 January 6 to 13). ZHRs could be ≈3 for most of March with a slight
increase derived from video flux data around λ⊙≈355◦(2020 March 17).
On 2015 January 10 at 02h50mUT, radar and video data showed a short outburst of the κ-
Cancrids (793 KCA; radiant at α= 138◦,δ= +9◦) at λ⊙= 289 .
◦315. Activity was also found
in the 2016 video data (Molau et al., 2016a). There is no report of activity in the subsequent
years. In 2020 the position is reached close to full Moon. Nevertheless, observers are encouraged
to check for possible meteors near 2020 January 10, 10 −11hUT. The radiant of the Antihelion
source centre is at α= 122◦,δ= +19◦, i.e. roughly 20◦southeast, and the KCA meteors
(V∞= 47 km/s) are faster than the ANT (V∞= 30 km/s).
From late January until April, the general meteor activity is on its lowest level. Hence it should
be possible to detect weak sources easily. Of course, video data are best suited for this purpose.
But visual observers should also take notes about meteor trails in case that sources are discovered
and subsequently may be confirmed by independent samples.
Expected approximate timings for the daytime shower maxima this quarter are:
Capricornids/Sagittariids (115 DCS) – February 1, 6hUT and χ-Capricornids (114 DXC) –
February 14, 5hUT. Recent radio results have implied the DCS maximum may fall variably
sometime between February 1–4 however, while activity near the expected DXC 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 (010 QUA)
Active: December 28–January 12; Maximum: January 4, 08h20mUT (λ⊙= 283 .
◦15),
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.
The first quarter Moon (January 3) will set near local midnight and thus leaves good viewing
conditions for the expected Quadrantid maximum on January 4. For many northern hemisphere
sites, the shower’s radiant in northern Bo¨otes is circumpolar. Depending on the observer’s
latitude, the radiant attains a useful elevation around or after local midnight and culminates
close to dawn.
Dec 30
Jan 01
05
10
15
QUA
IMO INFO(2-19) 5
The 08hUT timing for the peak will be favourable North America. European observers should
expect a continuous increase of the rates into dawn. The λ⊙= 283 .
◦15 maximum timing is based
on the best-observed return of the shower ever analysed, from IMO data collected in 1992. This
was confirmed by various later observations. In video meteor flux profiles of recent years, the
peak occurred at λ⊙= 283 .
◦11 (i.e. an hour earlier). The peak is short-lived with an average
duration (full width at half-maximum, FWHM – that is the period with ZHR above half of
the peak level) of about four hours. Hence it can be easily missed if the observer is located
outside the “main observing window” (high radiant in nighttime) or just a few hours of poor
northern-winter weather. Additional complexity comes from the mass-sorting of particles across
the meteoroid stream which is related to the minor planet 2003 EH1and to comet 96P/Machholz.
Fainter (radio/radar) meteors reach maximum up to 14 hours before the brighter (visual and
photographic) ones. Mass segregation effects have also been found for a small peak preceding
the main maximum in 2016. On a few returns, a maximum following the main visual one by
some 9–12 hours occurred in radio data. Therefore observers should be alert throughout the
shower activity period to record possible peculiarities.
γ-Normids (118 GNO)
Active: February 25–March 28; Maximum: March 14 (λ⊙= 354◦) – see text; ZHR = 6;
Radiant: α= 239◦,δ=−50◦, Radiant drift: see Table 6;
V∞= 56 km/s; r= 2.4.
The γ-Normid ZHRs seem to be virtually undetectable above the background sporadic rate for
most of the activity period. An analysis of IMO data from 1988–2007 showed an average peak
ZHR ≈6 at λ⊙= 354◦, with ZHRs <3 on all other dates during the shower (WB, p. 19). Results
since 1999 indicate the possibility of a short-lived peak alternatively between λ⊙≈347◦–357◦,
equivalent to 2020 March 7–17. Recent video and visual plotting information confirmed activity
from that region, but an analysis of video data obtained only from locations south of the equator
has indicated that the activity occurs preferentially around March 25 (λ⊙= 4◦) instead, from a
radiant at α= 246◦,δ=−51◦. The situation requires data to clarify the GNO activity issue.
Post-midnight watching yields better results, when the radiant is rising to a reasonable elevation
from southern hemisphere sites. Moonlight disturbs the March 14 period (gibbous waning) while
the possible March 25 timing occurs close to new Moon this year.
Feb 20
28
Mar 10
20
GNO
6IMO INFO(2-19)
4 April to June
Much of the meteor activity in late April into May remains unobservable for optical methods as
it is caused by daytime showers with their radiants too close to the Sun. But also the visually
accessible meteor rates increase with the moon-free Lyrids (006 LYR, also called April Lyrids)
and π-Puppids (137 PPU). The ascent towards the η-Aquariid (031 ETA) maximum can
be observed until just before the full Moon on May 7. Moonlight strongly affects the η-Lyrids
(145 ELY) with an expected peak on May 9 or slightly later. The June Bootids (170 JBO)
occur before the first quarter Moon on June 28.
There may be weak activity from the α-Virginids (021 AVB) related to the minor planet
2010GE35 on 2020 April 24 near 06h25mUT (λ⊙= 34 .
◦273) from a radiant α= 198◦,δ= +7◦,
showing slow meteors (V∞= 18 km/s), according to theoretical modelling of J´er´emie Vaubaillon.
This is more than 30◦apart from the ANT which is centred at α= 226◦,δ=−17◦.
Again referring to theoretical modelling of J´er´emie Vaubaillon, the meteoroids of the Apollo
object 461852 (2006 GY2) pass the Earth slightly outside the Earth’s orbit in 2020. Nevertheless,
there may be a weak activity of slow meteors (V∞= 19 km/s) on 2020 May 14 near 22hUT
(λ⊙= 54 .
◦279) from a radiant at α= 248◦,δ= +46◦(less than 2◦east of τHerculis). Although
at best some low activity is expected, any confirmation of the existence of the shower and the
link with 461852 is welcome.
According to analyses of visual and video IMO data, the ANT should produce ZHRs between
2 and 4 with insignificant variations. There may be a rather slow increase towards end-May
followed by a decrease into July. 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 (charts see facing page).
Daytime showers: In the second half of May and throughout June, most of the annual meteor
action switches to the daylight sky, with several shower peaks expected during this time. For
radio observers, we list the UT peak times for these showers (see also the remark below):
April Piscids (144 APS) – April 22, 10h;
ε-Arietids (154 DEA) – May 9, 3h;
May Arietids (294 DMA) – May 16, 4h;
o-Cetids (293 DCE) – May 20, 3h;
Arietids (171 ARI) – June 7, 4h(more details see page 10);
ζ-Perseids (172 ZPE) – June 9, 6h;
β-Taurids (173 BTA) – June 28, 5h.
Signs of most were found in radio data from 1994–2008, though some are difficult to define
individually because of the proximity of radiants. The maxima of the Arietids and ζ-Perseids
tend to blend into one another, producing a strong radio signature for several days in early to mid
June. The shower maxima dates are not well established. An apparent modest recurring peak
around April 24 occurs perhaps due to combined rates from more than one shower. Problems of
shower identification concern the δ-Piscids (previously listed as having a peak on April 24). The
IAU list does not recognise this currently as a genuine shower. Similarly, there are problems in
identifying the o-Cetids in the IAU stream lists. The current number and abbreviation given
here for it is actually for the IAU source called the “Daytime ω-Cetid Complex”, because that
seems a closer match to the o-Cetids as defined by earlier reports.
IMO INFO(2-19) 7
20
Mar 10
20
30
Apr 10
20
30
May 10
20
ANT (Mar–May)
20
30
May 10
20
30
Jun 10
20
30
Jul 10
20
ANT (May–Jul)
Lyrids (006 LYR)
Active: April 14–30; Maximum: April 22, 07hUT (λ⊙= 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
The λ⊙= 32 .
◦32 (2020 April 22, 06h40mUT) timing given above is the ideal maximum position
found in IMO results from 1988–2000. However, the maximum time was variable from year to
year between λ⊙= 32 .
◦0–32 .
◦45 (equivalent to 2020 April 21, 22h40mto April 22, 09h40mUT).
Activity was variable too. Peaks at the ideal time produced the highest ZHRs, ≈23. The
further the peak happened from this, the lower the ZHRs were, down to ≈14 – a relation which
needs to be confirmed. The mean peak ZHR was 18 over the thirteen years examined. Further,
the shower’s peak length varied: using the FWHM time (for explanation see the QUA text on
page 5), a variation between 14.8 to 61.7 hours was detected (mean 32.1 hours). The best rates
are normally achieved for just a few hours. The analysis also confirmed that occasionally, as
8IMO INFO(2-19)
their highest rates occurred, the Lyrids produced a brief increase in fainter meteors. In 1982 a
short-lived ZHR of 90 was recorded. For 2020 there are no predictions for any activity increase
from theoretical modelling.
Lyrid meteors are best viewed from the northern hemisphere, but are visible from many sites
north and south of the equator. As the radiant rises during the night, watches can be carried
out usefully after about 22h30mlocal time from mid-northern sites, but only well after midnight
from the mid-southern hemisphere. New Moon on April 23 provides optimal conditions for Lyrid
observations in 2020. The given activity period of the Lyrids is based on recent video and visual
data which report recognizable numbers of shower meteors until the end of April.
π-Puppids (137 PPU)
Active: April 15–28; Maximum: April 23, 12hUT (λ⊙= 33 .
◦5);
ZHR = variable, up to around 40;
Radiant: α= 110◦,δ=−45◦; Radiant drift: see Table 6;
V∞= 18 km/s; r= 2.0.
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,
IMO INFO(2-19) 9
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. The comet passed its perihelion last in 2013 and on 2018
October 1. Not unexpectedly, nothing meteorically significant happened in either year. When
this Calendar was prepared, no predictions for any 2020 π-Puppid meteor activity had been
issued. The π-Puppids are best-seen from the southern hemisphere, with useful observations
mainly practical before midnight, as the radiant is very low to setting after 01hlocal time.
The lunar phase is helpful for optical observations this year. Covering whatever transpires is
important, even if that is to report no obvious activity. The IMO data over the past 15 years
have only records of 2018 and 2019 which confirm low, but detectable rates.
η-Aquariids (031 ETA)
Active: April 19–May 28; Maximum: May 5, 21hUT (λ⊙= 45 .
◦5);
ZHR = 50 (periodically variable, ≈40–85);
Radiant: α= 338◦,δ=−1◦; Radiant drift: see Table 6;
V∞= 66 km/s; r= 2.4.
This stream is associated with Comet 1P/Halley, like the Orionids of October. Shower meteors
are only visible for a few hours before dawn essentially from tropical and southern hemisphere
sites. The radiant culminates near 8hlocal time. Useful results may be obtained even from
places around 40◦N latitude. The shower is one of the best for southern observers and would
benefit from increased observer activity generally. The fast and often bright meteors make the
wait for radiant-rise worthwhile, and many events leave persistent trains.
A relatively broad maximum, sometimes with a variable number of submaxima, occurs around
May 5/6. IMO analyses of visual data collected since 1984 have shown that ZHRs are generally
above 30 in the period May 3–10. The peak rates appear to be variable on a roughly 12-year
timescale. Assuming this Jupiter-influenced cycle is real, the next high level returns may occur
in the years 2020–2022. Recent peak ZHRs were:
2008 2009 2017 2018 2019
≈85 ≈70 75 60 50 (preliminary)
The waxing gibbous Moon (full on May 7) leaves a suitable moonless morning observation
window to follow the activity until the maximum night.
10 IMO INFO(2-19)
Daytime Arietids (171 ARI)
Active: May 14–June 24 (uncertain); Maximum: June 07 (λ⊙= 76 .
◦6);
ZHR ≈30(?);
Radiant: α= 44◦,δ= +24◦; Radiant drift: see Table 6;
V∞= 38 km/s; r= 2.8.
The radiant is located only about 30◦west of the Sun, hence possibilities for optical observations
are very limited. The low radiant elevation by the time morning twilight is too bright means
the number of shower meteors recorded by individual video or visual observers is always low.
Consequently, an ongoing IMO project to pool data on the shower using all techniques was
initiated in 2014, to combine results from many independent observing intervals, even those
periods which contain few, or even no ARI meteors. The currently available video data do not
show a clear profile but a recognizable activity level (indicating an even higher ZHR as given
above) over a week or so. Hence all contributions for this project will be most welcome! Since
both the correction factor for radiant elevation and the observing conditions change rapidly in
the approach to morning twilight in early June, it is recommended that visual observers break
their watches into short intervals (of the order of about 15 minutes), determining the limiting
magnitude frequently for each interval. Observers at latitudes south of about 30◦N are better
placed because of the significantly poorer twilight conditions further north in June. Since the
twilight brightness is the main limiting factor, the lunar phase probably does not cause the major
problem (full Moon on June 5).
June Bo¨otids (170 JBO)
Active: June 22–July 2; Maximum: June 27, 22hUT (λ⊙= 95 .
◦7), but see text;
ZHR = variable, 0–100+;
Radiant: α= 224◦,δ= +48◦; Radiant drift: see Table 6;
V∞= 18 km/s; r= 2.2.
This shower is listed since its unexpected return of 1998 (ZHR 50 −100+ for more than half
a day). Another outburst of similar length (ZHR ≈20 −50) was observed on 2004 June 23.
The return predicted in 2010 yielded a poorly established ZHR <10 on June 23–24. Prior to
1998, only three more probable returns had been detected, in 1916, 1921 and 1927 (however,
with different reliability).
The orbit of the parent comet 7P/Pons-Winnecke (orbital period about 6.4 years, last perihelion
passage on 2015 January 30) currently lies around 0.24 astronomical units outside the Earth’s
at its closest approach. The 1998 and 2004 events resulted from meteoroids ejected from the
IMO INFO(2-19) 11
comet in the past when the comet was still in a different orbit. For the 2020 return, there are no
predictions of peculiar activity published. We encourage all observers to monitor throughout the
proposed period, in case of any activity. From mid-northerly latitudes the radiant is observable
almost all night, but the prolonged – in some places continuous – twilight overnight keeps the
useable time short. This year, the Moon reaches its first quarter on June 28. VID suggested
some June Bo¨otids may be visible in most years around June 20 −25 but with activity largely
negligible except near λ⊙= 92◦(2020 June 23), radiating from a radiant at α= 216◦,δ= +38◦
which is about ten degrees south of the radiant found in 1998 and 2004.
5 July to September
The ANT is the chief focus for visual attention in the first half of July, as its radiant area moves
steadily through eastern Sagittarius, then across northern Capricornus into southwest Aquarius.
ZHRs for most of the month should be ≈2 to 3. The large ANT radiant area overlaps that
of the minor α-Capricornids (001 CAP) in July–August, but the lower apparent velocity of
the CAP allows observers to separate the two. The Southern δ-Aquariids (005 SDA) are
strong enough, and the Piscis Austrinids (183 PAU) have a radiant distant enough from
the ANT area, that both should be more easily separable from the ANT, particularly from the
southern hemisphere. The waxing gibbous Moon after July 27 will have an increasing impact in
the closing days of July on the observation during the highest rates from these southern radiants,
which are due on July 27 (PAU) and July 30 (CAP, SDA), respectively.
30
Jul 10
20
30
Aug 10
20
30
Sep 10
20
Jul 05
10
15
20
25
30
Aug 05
10
CAP
Jul 10
15
20
25
30
Aug 05
10
15
20
SDA
Jul 15
20
25
30
Aug 05
10
PAU
ANT
The waning Moon (at last quarter on August 11) will still allow some useful observations of the
Perseids (007 PER) from their maximum onwards. Favourable conditions are found for the
minor κ-Cygnids (012 KCG). The Aurigid (206 AUR) peak on August 31 occurs shortly
before full Moon (on September 2) and there are no predictions for known activity enhancements
in 2020 from this source. The most interesting activity of the September ε-Perseids (208
SPE) is difficult to record this year because the last quarter Moon (September 10) in a high
northern position will illuminate the essential time after local midnight. J´er´emie Vaubaillon’s
calculations hint at possible activity caused by trails ejected in 1848 and 1375 (September 9 at
09h55mUT and 13h32mUT, respectively).
12 IMO INFO(2-19)
On 2016 July 28 at 00h07mUT (λ⊙= 125 .
◦132) a remarkable outburst (ZHR probably of
the order of 100) of the July γ-Draconids (184 GDR) was detected by radar and video
observations (Molau et al., 2016b). The same position is reached again on 2020 July 28 near
00h30mUT, well worth checking in case something may be observable around this time – despite
the lunar circumstances in July noted above. The radiant is at α= 280◦,δ= +51◦, and the
meteors have rather low speed (V∞= 27 km/s).
A possible activity of the β-Hydrusids from a radiant at α= 23◦,δ=−76◦on 2020 August
16 at 14h18mUT (λ⊙= 143 .
◦886) is listed in Table 3 of Peter Jenniskens (2006). There is only
one previous set of observations of this shower from 1985 August 16 from Australia (Jenniskens
2006, p. 346). The 2020 timing would be an encounter with a 1-revolution trail of an unknown
Jupiter family comet. The radiant is far south and any meteors can only be recorded from the
southern hemisphere. The velocity of the shower meteoroids is V∞= 24 km/s.
In 2015, several video data sets showed low rates had persisted essentially throughout September,
identified as originating with the χ-Cygnids (757 CCY). A weak maximum was found on
September 14/15 (ZHRs about 2 or 3). The shower was also suspected in previous years, but
at a lower activity level, hence further observations would be useful. New Moon on September
17 provides excellent conditions for optical observations to improve our knowledge of this minor
source. The radiant of these very slow meteors (V∞= 19 km/s) is at α= 300◦,δ= +31◦. For
convenience, we have included the radiant drift in Table 6.
Remember that the Southern Taurids (002 STA) begin around September 10, effectively
taking over the near-ecliptic activity from the ANT through to December.
For daylight radio observers, the high activity of May–June has waned, but there remain
the γ-Leonids (203 GLE; peak due near August 24, 23hUT, albeit not found in recent radio
results), and the Daytime Sextantids (221 DSX). From late September to early October
optical observers are encouraged to collect data of the DSX (see on page 14), too.
Perseids (007 PER)
Active: July 17–August 24; Maximum: August 12, 13hto 16hUT (node at λ⊙= 140 .
◦0–
140 .
◦1), but see text; ZHR = 110;
Radiant: α= 48◦,δ= +58◦; Radiant drift: see Table 6;
V∞= 59 km/s; r= 2.2.
IMO observations (see WB pp. 32–36) found the timing of the mean or ‘traditional’ broad
maximum varied between λ⊙≈139 .
◦8 to 140 .
◦3, equivalent to 2020 August 12, 08hto August
12, 21hUT. The orbital period of the parent comet 109P/Swift-Tuttle is about 130 years. The
Perseids produced strong activity from a primary maximum throughout the 1990s. Enhanced
activity was last observed in 2016 with additional peaks due to passages through separated dust
trails. A filament crossing has been recovered from the 2018 data. It occurred on August 12
around 20hUT (λ⊙≈139 .
◦79) at the predicted position. The filament is thought to be an
accumulation of meteoroids in a mean-motion resonance. A similar filament encounter (ZHR
about 100) is listed in Table 5d of Jenniskens (2006) for 2020. Its calculated position is close to
the early maximum period at λ⊙≤139 .
◦89 (2020 August 12, ≈10hUT).
The last quarter Moon on August 11 illuminates the favourable hours after local midnight. Visual
observers should try to block the direct moonlight. Generally, sites at mid-northern latitudes
are best for Perseid observing, as from here, the shower’s radiant can be usefully observed from
22h–23hlocal time onwards. Regrettably, the shower cannot be properly viewed from most of
the southern hemisphere.
IMO INFO(2-19) 13
κ-Cygnids (012 KCG)
Active: August 3–25; Maximum: August 17 (λ⊙= 145◦); ZHR = 3;
Radiant: α= 286◦,δ= +59◦; Radiant drift: see Table 6;
V∞= 25 km/s; r= 3.0.
The κ-Cygnids showed enhanced activity in 2014 and 2007. Apart from these events, the general
ZHR level seems to increase in the recent years, from an apparent dip in the period 1990–2005.
However, the currently-available data do not confirm a periodic activity variation in the visual
activity range, and for 2020 there are no available predictions suggesting further peculiarities
may occur.
VID suggested a number of discrepancies to the currently-accepted parameters listed above,
including that the peak might happen closer to August 14, and that activity might be present
only from August 6–19 overall. Research by Koseki (2017) has shown a complex radiant structure
extending into Draco and Lyra. The isolated radiant position and the low velocity should be
used to associate KCG meteors to the complex. The shower is best-observed from northern
hemisphere sites, from where the radiant is easily available all night.
14 IMO INFO(2-19)
Daytime Sextantids (221 DSX)
Active: September 9–October 9 (uncertain); Maximum: September 27 (λ⊙= 184 .
◦3),
Radiant: α= 152◦,δ= 0◦; Radiant drift: 1◦per day;
V∞= 32 km/s; r= 2.5 (uncertain).
Visual observers may observe some Sextantids in the pre-dawn of late September to early October
as part of the IMO project to collect and pool data obtained by all techniques for this shower. The
DSX radiant is roughly 30◦west of the Sun. Because it lies close to the equator and the activity
period is shortly after the equinox, the chances to contribute results are almost equally good
for observers in either hemisphere. As with the Arietids, both the radiant elevation correction
and the observing conditions change rapidly as morning twilight approaches. Hence visual
observers should report their data in intervals no longer than about 15–20 minutes, determining
the limiting magnitude frequently during each period. The timing, and even the date, of the
Sextantid maximum is uncertain. The waxing gibbous Moon (at first quarter on September 24)
will not affect pre-dawn DSX observing attempts.
6 October to December
During the last quarter of the year the most active showers are observable under good lunar
conditions: both the Orionids (008 ORI) and the Leonids (013 LEO) reach their maxima
shortly after new Moon and the Geminid (004 GEM) peak coincides with the new Moon.
The October Camelopardalids (281 OCT) produced a well detected ZHR ≈5 on 2018
October 6, 00h30mUT ±1.3h(192 .
◦45 ±0.
◦05). The same position is reached again on 2020
October 5, 12h40mUT which is just four days after full Moon. Hence any activity will be
difficult to observe. On October 8, the Draconids may show some additional activity. Further
good targets – moonlight considering – are the ε-Geminids (023 EGE) on October 18 and
the Leonis Minorids (022 LMI) on October 24. A month later, the α-Monocerotids
(246 AMO) on November 21 are promising, and in December we find favourable conditions
to observe the Monocerotids (MON) and the σ-Hydrids (HYD), both with their maxima
close to the Geminids. Suffering from moonlit skies are the δ-Aurigids (224 DAU) on October
11. This also holds for the November Orionids (250 NOO, maximum on November 28) and
the Phoenicids (254 PHO, maximum on December 2). Bright moonlight affects observations
of the complex Puppid-Velids (301 PUP) around December 7. Next, the weak Comae
Berenicids (020 COM) on December 16 can be traced well while the long-lasting December
Leonis Minorids (032 DLM) offer better observing conditions away from their weak maximum
around December 20. During the Ursid (URS) maximum the waxing gibbous Moon leaves a
rather short morning observation window to observe interesting regions of the stream.
The two Taurid branches reach their highest rates around October 10 (STA) and November 12
(NTA), both dates close to the Moon’s last quarter. The ANT start into the fourth quarter of
the year effectively inactive in favour of the Taurids, resuming only around December 10, as the
Northern Taurids fade away, from a radiant centre that tracks across southern Gemini during
later December, likely producing ZHRs <2.
The Near Earth Object 2015 TB145 is suspected to be an extinct comet nucleus. If it was
recently active, the Earth may encounter the associated meteoroid stream on 2020 October
20 at 22h09mUT (λ⊙= 217 .
◦659) according to the calculations of J´er´emie Vaubaillon. The
theoretical radiant is at α= 64◦,δ=−3◦, less than 5◦west of νEridani. Depending on the
latitude, the radiant rises at about 21hlocal time. The shower meteors have medium velocity
(V∞= 34 km/s).
IMO INFO(2-19) 15
In December 2016, observers had been alerted that some meteors of the 66-Draconids associ-
ated with the minor planet 2001 XQ could be possible. In visual data the activity remained below
the detection limit. According to dynamical modelling results for 2020 by J´er´emie Vaubaillon,
there might be another encounter of a highly perturbed trail. The calculated time is on Decem-
ber 4, 05h55mUT (λ⊙= 252 .
◦26), and the theoretical radiant is at α= 314◦,δ= +60◦, i.e.
between Draco and Cepheus in a circumpolar position for most mid-Northern latitudes. The
meteors are very slow with V∞= 17 km/s so that shower association should be easy. Any reports
around the predicted period are welcome.
Draconids (009 DRA)
Active: October 6–10; Maximum: October 8, 12h30mUT (λ⊙= 195 .
◦4), but see text;
ZHR = 10+ (?);
Radiant: α= 263◦,δ= +56◦; Radiant drift: negligible;
V∞= 21 km/s; r= 2.6.
The Draconids (also called October Draconids) are known as a periodic shower which produced
spectacular meteor storms in 1933 and 1946, and lower rates in several other years (ZHRs ≈20–
500+). Recent outbursts happened in 2011 (ZHR ≈300) and wholly unexpectedly in 2012
(chiefly very faint meteors, detected primarily by the Canadian CMOR meteor radar system).
The 2018 return yielded a ZHR of about 150 lasting for about 4 hours, much higher than the
predicted values. For 2020, there will be two trail encounters based on calculations by J´e´remie
Vaubaillon, both with no rate estimate. The respective times are from Jenniskens (2006):
1704 trail: 2020 October 7, 01h25mUT,
1711 trail: 2020 October 7, 01h57mUT.
Both are significantly ahead of the near-nodal period. The Moon (last quarter on October 10)
is not disturbing in the evening hours which are best for Draconid observations. The radiant
is north-circumpolar, at its highest during the first half of the night, and Draconid meteors are
exceptionally slow-moving.
Southern Taurids (002 STA
Active: September 10–November 20; Maximum: October 10 (λ⊙= 197◦); ZHR = 5;
Radiant: α= 32◦,δ= +09◦; Radiant drift: see Table 6;
V∞= 27 km/s; r= 2.3.
This stream, with its Northern counterpart, forms part of the complex associated with Comet
2P/Encke. For shower association, assume the radiant to be an oval area, about 20◦in αby 10◦
16 IMO INFO(2-19)
in δ, centred on the radiant position for any given date. The Taurid activity overall dominates
the Antihelion Source area’s during the northern autumn, so much so that the ANT is considered
inactive while either branch of the Taurids is present. The brightness and relative slowness of
many Taurid meteors makes them ideal targets for still-imaging, while these factors coupled with
low, steady, Taurid rates makes them excellent subjects for newcomers to practice their visual
plotting techniques on. The Southern branch of the Taurids reaches its peak about a month
before the Northern one, this year around the last quarter Moon. Its near-ecliptic radiant makes
the shower a target for observers at all latitudes, albeit those in the northern hemisphere are
somewhat better-placed, as here suitable radiant zenith distances persist for much of the night.
ε-Geminids (023 EGE)
Active: October 14–27; Maximum: October 18 (λ⊙= 205◦); ZHR = 3;
Radiant: α= 102◦,δ= +27◦; Radiant drift: see Table 6;
V∞= 70 km/s; r= 3.0.
A weak minor shower with characteristics and activity nearly coincident with the Orionids, so
great care must be taken to separate the two sources (chart see on page 17). Visual observers may
prefer plotting to improve the shower association. The waxing crescent Moon on October 18/19
will set before the radiant becomes usefully observable from either hemisphere. Northern ob-
servers have a radiant elevation advantage, with observing practical there from about midnight
onwards. There is some uncertainty about the shower’s parameters, with both visual and video
data indicating the peak may be up to four or five days later than suggested above.
Orionids (008 ORI)
Active: October 2–November 7; Maximum: October 21 (λ⊙= 208◦); ZHR = 20+;
Radiant: α= 95◦,δ= +16◦; Radiant drift: see Table 6;
V∞= 66 km/s; r= 2.5.
October’s waxing crescent Moon sets well before local midnight for the peak night of Octo-
ber 20/21 this year. The shower’s radiant is at a useful elevation from local midnight or so
in either hemisphere, somewhat before in the north. Each return from 2006 to 2009 produced
unexpectedly strong ZHRs of around 40–70 on two or three consecutive dates. An earlier IMO
IMO INFO(2-19) 17
analysis of the shower, using data from 1984–2001, found both the peak ZHR and rparameters
varied somewhat from year to year, with the highest mean ZHR ranging from ≈14–31 during the
examined interval. In addition, a suspected 12-year periodicity in stronger returns found earlier
in the 20th century appeared to have been partly confirmed. That suggested the higher activity
phase of the cycle should fall between 2020–2022. The average maximum Orionid ZHRs in the
years 2014–2018 was in the range of 20–25. The Orionids often provide several lesser maxima,
helping activity sometimes remain roughly constant for several consecutive nights centred on the
main peak. In 1993 and 1998, a submaximum about as strong as the normal peak was detected
on October 17/18 from Europe, for instance.
Leonis Minorids (022 LMI)
Active: October 19–27; Maximum: October 24 (λ⊙= 211◦); ZHR = 2;
Radiant: α= 162◦,δ= +37◦; Radiant drift: See Table 6;
V∞= 62 km/s; r= 3.0.
This weak minor shower has a peak ZHR apparently close to the visual threshold, found so far
mainly in video data. The radiant area can be seen solely from the northern hemisphere, where
it rises around midnight. The probable maximum date falls just after the first quarter Moon, so
it is well placed for coverage! All kinds of observations are advised.
18 IMO INFO(2-19)
Northern Taurids (017 NTA)
Active: October 20–December 10; Maximum: November 12 (λ⊙= 230◦); ZHR = 5;
Radiant: α= 58◦,δ= +22◦; Radiant drift: see Table 6;
V∞= 29 km/s; r= 2.3.
Some details on this branch of the Taurid streams were given with the Southern Taurids above.
Other aspects are the same too, such as the large, oval radiant region to be used for shower
association, the shower’s excellent visibility overnight, and its dominance over the ANT during
September to December. As previous results had suggested seemingly plateau-like maximum
rates persisted for roughly ten days in early to mid November, the NTA peak may not be
so sharp as its single maximum date might imply. Whatever the case, last quarter Moon on
November 8 should allow plenty of coverage. (For the radiant drift graph see page 16.)
Leonids (013 LEO)
Active: November 6–30; Maximum: November 17, 11hUT (nodal crossing at λ⊙= 235 .
◦27);
ZHR ≈10 −20
Radiant: α= 152◦,δ= +22◦; Radiant drift: see Table 6;
V∞= 71 km/s; r= 2.5.
The latest perihelion passage of the Leonids’ parent comet, 55P/Tempel-Tuttle, in 1998 is more
than two decades ago now and meanwhile the comet has passed its aphelion. The knowledge
of the dust ejection mechanisms and trail evolution allowed us to predict and verify variable
activity in numerous years until recently. The nodal Leonid maximum occurs on November 17
just after new Moon.
Mikiya Sato’s model calculation shows that there are a few dust trail approaches in 2020. Some
activity of predominantly faint meteors may occur on November 17 between 06h50m−08h13mUT
(λ⊙= 235 .
◦100−235 .
◦158). The meteoroids of the 1600-trail are leading the comet, like the trails
due in the following years. Hence the data of 2020 have high relevance for the next predictions.
Further approaches in 2020 concern trails of 901 (November 18, 00h58mUT, λ⊙= 235 .
◦852)
and 1234 (November 20, 15h28mUT, λ⊙= 238 .
◦490). Both are probably at the detection limit
because perturbations reduced the density a lot. The shower’s radiant is usefully observable only
by local midnight or so north of the equator, afterwards for places further south.
IMO INFO(2-19) 19
α-Monocerotids (246 AMO)
Active: November 15–25; Maximum: November 21, 12hUT (λ⊙= 239 .
◦32);
ZHR = variable, usually ≤5, but see text;
Radiant: α= 117◦,δ= +01◦; Radiant drift: see Table 6;
V∞= 65 km/s; r= 2.4.
The most recent α-Monocerotid outburst was observed in 1995. The peak ZHR of ≈420 lasted
for just five minutes, the entire outburst 30 minutes. Recent modelling by Esko Lyytinen has
indicated the main AMO trail crosses the Earth’s orbit in 2017 and 2020. However, the Earth is
not near those points in November, so no strong outburst is likely to happen then. The possible
return of November 2019 still had to come when the Calendar was written. Observable rates in
2019 may indicate some low activity also on 2020 November 21, 09h50mUT (λ⊙= 239 .
◦264).
The next strong AMO outburst is unlikely before 2043. Despite all this, observers are advised to
monitor the AMO annually to complete our knowledge about this stream. First quarter Moon
on the maximum date sets around local midnight when the radiant reaches suitable elevation
above the horizon.
Monocerotids (019 MON)
Active: November 27–December 20; Maximum: December 9 (λ⊙= 257◦); ZHR = 3;
Radiant: α= 100◦,δ= +08◦; Radiant drift: see Table 6;
V∞= 42 km/s; r= 3.0.
This minor shower’s details need further improvement by observational data. In most years,
visual data give a maximum ZHR = 3 at λ⊙≈257◦while the general ZHR level is about 2.
In a few years, we also find an apparent slight enhancement in the Geminid peak night. This
is assumed to be an effect of Geminids erroneously classified as MON. Video data (2011–2018)
show a peak of roughly 0 .
◦4 width centred at λ⊙≈262 .
◦0◦(i.e. December 14) with a ZHR of
the order of 8 coinciding with the Geminid peak. Care needs to be taken to clearly distinguish
MON from GEM. Visual observers should choose their field of view such, that the radiants do
not line up. (Field centres near Taurus in the evening or near Leo in the morning are possible
choices.) December’s new Moon period creates perfect conditions for either potential maximum
timing, as the radiant area is available virtually all night for much of the globe, culminating at
about 01h30mlocal time.
20 IMO INFO(2-19)
σ-Hydrids (016 HYD)
Active: December 3–20; Maximum: December 9 (λ⊙= 257◦); ZHR = 7;
Radiant: α= 125◦,δ= +02◦; Radiant drift: see Table 6;
V∞= 58 km/s; r= 3.0.
The σ-Hydrids are often thought to be a very minor shower with rates close to the visual detection
threshold for much of the activity period. However, some bright meteors are repeatedly seen
and the maximum ZHR reaches 5–8. IMO visual data (WB p. 65) have indicated the maximum
might happen nearer λ⊙∼262◦(December 14). This is probably an effect as described for the
MON caused by mis-aligned Geminids. Visual IMO data from the period 2010–2018 show a
maximum close to λ⊙∼257◦(December 9) and the Geminid-related feature only in a few years.
VID implied a peak closer to λ⊙∼254◦(December 6), and that HYD activity might persist till
December 24. A careful choice of the observing field is necessary to distinguish HYD from GEM
and MON which are active at the same time (see notes in the MON section above). Since the
HYD radiant rises in the late evening hours, it is best viewed after local midnight from either
hemisphere. 2020 is a splendid year for them, thanks to new Moon on December 14.
IMO INFO(2-19) 21
Geminids (004 GEM)
Active: December 4–17; Maximum: December 14, 00h50mUT (λ⊙= 262 .
◦2); ZHR = 150;
Radiant: α= 112◦,δ= +33◦; Radiant drift: see Table 6;
V∞= 35 km/s; r= 2.6.
The best and most reliable of the major annual showers presently observable reaches its broad
maximum on December 14 centred at 01hUT. Well north of the equator, the radiant rises
about sunset, reaching a usable elevation from the local evening hours onwards. In the southern
hemisphere, the radiant appears only around local midnight or so. It culminates near 02hlocal
time. Even from more southerly sites, this is a splendid stream of often bright, medium-speed
meteors, a rewarding event for all observers, whatever method they employ.
The peak has shown little variability in its timing in recent years, with the more reliably-reported
maxima during the past two decades (WB, p. 66) all having occurred within λ⊙= 261 .
◦5 to
262 .
◦4, that is 2020 December 13, 08hto December 14, 06hUT. The peak ZHRs have shown a
slight increase over a longer period and reached 140–150 in all recent years. Usually, near-peak
Geminid rates persist for several hours, so much of the world has the chance to enjoy something
of the shower’s best. Mass-sorting within the stream means fainter meteors should be most
abundant almost a day ahead of the visual maximum. The 2020 return coincides with new
Moon and is therefore optimally placed.
Ursids (015 URS)
Active: December 17–26; Maximum: December 22, 09hUT (λ⊙= 270 .
◦7) and see text;
ZHR = 10 (occasionally variable up to 50);
Radiant: α= 217◦,δ= +76◦; Radiant drift: see Table 6;
V∞= 33 km/s; r= 3.0.
A poorly-observed northern hemisphere shower which has produced at least two major outbursts
in the past 70 years, in 1945 and 1986. Some events could have been missed due to weather
conditions. Several lesser rate enhancements have been reported from 2006 to 2008. Many peaks
occurred when the parent was close to its aphelion, and so the slightly enhanced rates found in
video data in 2014 and 2015 indicate that predictions are difficult.
22 IMO INFO(2-19)
For 2020, Jenniskens (2006) lists encounters of two dust trails based on Lyytinen’s calculations
and one filament of meteoroids in a mean-motion resonance. The respective times are:
829 dust trail, December 22, 06h10mUT (270 .
◦57)
815 dust trail, December 22, 03h−22hUT (270 .
◦44)
filament, December 22, 05h27mUT (270 .
◦54)
The listed ZHRs are 490 and 420 for the trails and 34 for the filament, respectively. Both, the
timing and the rates may include valuable information about the modelling parameters.
Mikiya Sato finds two periods when some detectable activity is to be expected:
719 + 733 dust trails, December 22, 03h15m−03h40mUT (270 .
◦449 −270 .
◦463)
801 dust trail, December 22, 17h31mUT (271 .
◦053)
Comparing the condition with previous returns, the rates will be low.
The Ursid radiant is circumpolar from most northern sites, so fails to rise for most southern
ones, though it culminates after daybreak, and is highest in the sky later in the night. The
Moon (first quarter on December 21) and the long northern nights allow observations for several
hours at each suitable location.
7 Radiant sizes and meteor plotting for visual observers
by Rainer Arlt
If you are not observing during a major-shower maximum, it is essential to associate meteors with
their radiants correctly, since the total number of meteors will be small for each source. Meteor
plotting allows shower association by more objective criteria after your observation than the
simple imaginary back-prolongation of paths under the sky. With meteors plotted on gnomonic
maps, you can trace them back to their radiants by extending their straight line paths. If a
radiant lies on another chart, you should find common stars on an adjacent chart to extend this
back-prolongation correctly.
How large a radiant should be assumed for shower association? The real physical radiant size is
very small, but visual plotting errors cause many true shower meteors to miss this real radiant
area. Thus we have to assume a larger effective radiant to allow for these errors. Unfortunately,
as we enlarge the radiant, so more and more sporadic meteors will appear to line up accidentally
with this region. Hence we have to apply an optimum radiant diameter to compensate for the
plotting errors loss, but which will not then be swamped by sporadic meteor pollution. Table 1
gives this optimum diameter as a function of the distance of the meteor from the radiant.
IMO INFO(2-19) 23
Table 1. Optimum radiant diameters to be assumed for shower association of
minor-shower meteors as a function of the radiant distance Dof the meteor.
Doptimum diameter
15◦14◦
30◦17◦
50◦20◦
70◦23◦
Note that this radiant diameter criterion applies to all shower radiants except those of the
Southern and Northern Taurids, and the Antihelion Source. The optimum α×δsize to be
assumed for the STA and NTA is instead 20◦×10◦, while that for the ANT is still larger, at
30◦×15◦.
Path-direction is not the only criterion for shower association. The angular velocity of the meteor
should match the expected speed of the given shower meteors according to their geocentric
velocities. Angular velocity estimates should be made in degrees per second (◦/s). To do this,
make the meteors you see move for one second in your imagination at the speed you saw them.
The path length of this imaginary meteor is the angular velocity in ◦/s. Note that typical speeds
are in the range 3◦/s to 25◦/s. Typical errors for such estimates are given in Table 2.
Table 2. Error limits for the angular velocity.
angular velocity [◦/s] 5 10 15 20 30
permitted error [◦/s] 3 5 6 7 8
If you find a meteor in your plots which passes the radiant within the diameter given by Table 1,
check its angular velocity. Table 3 gives the angular speeds for a few geocentric velocities, which
can then be looked up in Table 5 for each shower.
Table 3. Angular velocities as a function of the radiant distance of the meteor (D) and the
elevation of the meteor above the horizon (h) for three different geocentric velocities (V∞). All
velocities are in ◦/s.
V∞= 25 km/s V∞= 40 km/s V∞= 60 km/s
h\D10◦20◦40◦60◦90◦10◦20◦40◦60◦90◦10◦20◦40◦60◦90◦
10◦0.4 0.9 1.6 2.2 2.5 0.7 1.4 2.6 3.5 4.0 0.9 1.8 3.7 4.6 5.3
20◦0.9 1.7 3.2 4.3 4.9 1.4 2.7 5.0 6.8 7.9 1.8 3.5 6.7 9.0 10
40◦1.6 3.2 5.9 8.0 9.3 2.6 5.0 9.5 13 15 3.7 6.7 13 17 20
60◦2.2 4.3 8.0 11 13 3.5 6.8 13 17 20 4.6 9.0 17 23 26
90◦2.5 4.9 9.3 13 14 4.0 7.9 15 20 23 5.3 10 20 26 30
8 References and Abbreviations
References:
Jenniskens P., 2006: Meteor showers and their parent comets. Cambridge Univ. Press
Koseki M., 2014: Various meteor scenes II: Cygnid-Draconid Complex (κ-Cygnids), WGN 42, pp. 181–
197.
24 IMO INFO(2-19)
Molau S., Crivello S., Goncalves R., Saraiva C., Stomeo E., Kac J., 2016a: Results of the IMO Video
Meteor Network – February 2016, WGN 44, pp. 116–119.
Molau S., Crivello S., Goncalves R., Saraiva C., Stomeo E., Kac J., 2016b: Results of the IMO Video
Meteor Network – July 2016, WGN 44, pp. 205–210.
Molau S., Rendtel, J., 2009: A comprehensive list of meteor showers obtained from 10 years of obser-
vations with the IMO Video Meteor Network, WGN 37:4, pp. 98–121
Rendtel J., 2014: Meteor Observers Workbook 2014 (ed.: J¨urgen Rendtel), IMO, 2014
Abbreviations:
•α,δ: Coordinates for a shower’s radiant position, usually at maximum. αis right ascension,
δis declination. Radiants drift across the sky each day due to the Earth’s own orbital
motion around the Sun, and this must be allowed for using the details in Table 6 for nights
away from the listed shower maxima.
•r: The population index, a term computed from each shower’s meteor magnitude distribu-
tion. r= 2.0–2.5 implies a larger fraction of brighter meteors than average, while rabove
3.0 is richer in fainter meteors than average.
•λ⊙: Solar longitude, a precise measure of the Earth’s position on its orbit which is not
dependent on the vagaries of the calendar. All λ⊙are given for the equinox 2000.0.
•V∞: Pre-atmospheric or apparent meteoric velocity, given in km/s. Velocities range from
about 11 km/s (very slow) to 72 km/s (very fast). 40 km/s is roughly medium speed.
•ZHR: Zenithal Hourly Rate, a calculated maximum number of meteors an ideal observer
would see in perfectly clear skies (reference limiting magnitude +6.5) with the shower
radiant overhead. This figure is given in terms of meteors per hour.
9 Tables: lunar and shower data
Table 4. Lunar phases for 2020.
New Moon First Quarter Full Moon Last Quarter
January 3 January 10 January 17
January 24 February 2 February 9 February 15
February 23 March 2 March 9 March 16
March 24 April 1 April 8 April 14
April 23 April 30 May 7 May 14
May 22 May 30 June 5 June 13
June 21 June 28 July 5 July 13
July 20 July 27 August 3 August 11
August 19 August 25 September 2 September 10
September 17 September 24 October 1 October 10
October 16 October 23 October 31 November 8
November 15 November 22 November 30 December 8
December 14 December 21 December 30
IMO INFO(2-19) 25
Table 5. Working List of Visual Meteor Showers. Details in this Table were correct
according to the best information available in June 2019, with maximum dates accurate only
for 2020. The parenthesized maximum date for the Puppids-Velids indicates a reference date
for the radiant only, not necessarily a true maximum. Some showers have ZHRs that vary from
year to year. The most recent reliable figure is given here, except for possibly periodic showers
which are noted as ‘Var’ = variable. For more information check the updates published e.g. in
the IMO Journal WGN.
Shower Activity Maximum Radiant V∞rZHR
Date λ⊙α δ km/s
Antihelion Source (ANT) Dec 10–Sep 10 March–April, see Table 6 30 3.0 4
– late May, late June
Quadrantids (010 QUA) Dec 28–Jan 12 Jan 04 283 .
◦15 230◦+49◦41 2.1 110
γ-Ursae Minorids (404 GUM) Jan 10–Jan 22 Jan 19 298◦228◦+67◦31 3.0 3
α-Centaurids (102 ACE) Jan 31–Feb 20 Feb 08 319 .
◦2 210◦−59◦58 2.0 6
γ-Normids (118 GNO) Feb 25–Mar 28 Mar 14 354◦239◦−50◦56 2.4 6
Lyrids (006 LYR) Apr 14–Apr 30 Apr 22 32 .
◦32 271◦+34◦49 2.1 18
π-Puppids (137 PPU) Apr 15–Apr 28 Apr 23 33 .
◦5 110◦−45◦18 2.0 Var
η-Aquariids (031 ETA) Apr 19–May 28 May 05 45 .
◦5 338◦−01◦66 2.4 50
η-Lyrids (145 ELY) May 03–May 14 May 08 48 .
◦0 287◦+44◦43 3.0 3
Dayt. Arietids (171 ARI) May 14–Jun 24 Jun 07 76 .
◦6 44◦+24◦38 2.8 30
June Bootids (170 JBO) Jun 22–Jul 02 Jun 27 95 .
◦7 224◦+48◦18 2.2 Var
Piscis Austr. (183 PAU) Jul 15–Aug 10 Jul 27 125◦341◦−30◦35 3.2 5
S. δ-Aquariids (005 SDA) Jul 12–Aug 23 Jul 29 127◦340◦−16◦41 2.5 25
α-Capricornids (001 CAP) Jul 03–Aug 15 Jul 29 127◦307◦−10◦23 2.5 5
Perseids (007 PER) Jul 17–Aug 24 Aug 12 140 .
◦0 48◦+58◦59 2.2 100
κ-Cygnids (012 KCG) Aug 03–Aug 25 Aug 17 145◦286◦+59◦25 3.0 3
Aurigids (206 AUR) Aug 28–Sep 05 Aug 31 158 .
◦6 91◦+39◦66 2.5 6
Sep. ε-Perseids (208 SPE) Sep 05–Sep 21 Sep 09 166 .
◦7 48◦+40◦64 3.0 5
Dayt. Sextantids (221 DSX) Sep 09–Oct 09 Sep 27 184 .
◦3 152◦+00◦32 2.5 5
Oct. Camelopard. (281 OCT) Oct 05–Oct 06 Oct 05 192 .
◦58 164◦+79◦47 2.5 5
Draconids (009 DRA) Oct 06–Oct 10 Oct 08 195 .
◦4 262◦+54◦20 2.6 10
S. Taurids (002 STA) Sep 10–Nov 20 Oct 10 197◦32◦+09◦27 2.3 5
δ-Aurigids (224 DAU) Oct 10–Oct 18 Oct 11 198◦84◦+44◦64 3.0 2
ε-Geminids (023 EGE) Oct 14–Oct 27 Oct 18 205◦102◦+27◦70 3.0 3
Orionids (008 ORI) Oct 02–Nov 07 Oct 21 208◦95◦+16◦66 2.5 20
Leonis Minorids (022 LMI) Oct 19–Oct 27 Oct 24 211◦162◦+37◦62 3.0 2
N. Taurids (017 NTA) Oct 20–Dec 10 Nov 12 230◦58◦+22◦29 2.3 5
Leonids (013 LEO) Nov 06–Nov 30 Nov 17 235 .
◦27 152◦+22◦71 2.5 15
α-Monocerotids (246 AMO) Nov 15–Nov 25 Nov 21 239 .
◦32 117◦+01◦65 2.4 Var
Nov. Orionids (250 NOO) Nov 13–Dec 06 Nov 28 246◦91◦+16◦44 3.0 3
Phoenicids (254 PHO) Nov 28–Dec 09 Dec 02 250 .
◦0 18◦−53◦18 2.8 Var
Puppid-Velids (301 PUP) Dec 01–Dec 15 (Dec 07) (255◦) 123◦−45◦40 2.9 10
Monocerotids (019 MON) Dec 05–Dec 20 Dec 09 257◦100◦+08◦41 3.0 3
σ-Hydrids (016 HYD) Dec 03–Dec 20 Dec 09 257◦125◦+02◦58 3.0 7
Geminids (004 GEM) Dec 04–Dec 20 Dec 14 262 .
◦2 112◦+33◦35 2.6 150
Comae Berenic. (020 COM) Dec 12–Dec 23 Dec 16 264◦175◦+18◦65 3.0 3
Dec. L. Minorids (032 DLM) Dec 05–Feb 04 Dec 19 268◦161◦+30◦64 3.0 5
Ursids (015 URS) Dec 17–Dec 26 Dec 22 270 .
◦7 217◦+76◦33 3.0 10
Table 6 (next page). Radiant positions during the year in αand δ.
26 IMO INFO(2-19)
Date ANT QUA DLM
Jan 0 112◦+21◦228◦+50◦172◦+25◦
Jan 5 117◦+20◦231◦+49◦176◦+23◦GUM
Jan 10 122◦+19◦234◦+48◦180◦+21◦220◦+71◦
Jan 15 127◦+17◦185◦+19◦224◦+69◦
Jan 20 132◦+16◦189◦+17◦228◦+67◦
Jan 25 138◦+15◦193◦+15◦ACE 232◦+65◦
Jan 30 143◦+13◦198◦+12◦200◦−57◦
Feb 5 149◦+11◦203◦+10◦208◦−59◦
Feb 10 154◦+9◦214◦−60◦
Feb 15 159◦+7◦220◦−62◦
Feb 20 164◦+5◦GNO 225◦−63◦
Feb 28 172◦+2◦225◦−51◦
Mar 5 177◦0◦230◦−50◦
Mar 10 182◦−2◦235◦−50◦
Mar 15 187◦−4◦240◦−50◦
Mar 20 192◦−6◦245◦−49◦
Mar 25 197◦−7◦250◦−49◦
Mar 30 202◦−9◦255◦−49◦
Apr 5 208◦−11◦
Apr 10 213◦−13◦LYR PPU
Apr 15 218◦−15◦263◦+34◦106◦−44◦ETA
Apr 20 222◦−16◦269◦+34◦109◦−45◦323◦−7◦
Apr 25 227◦−18◦274◦+34◦111◦−45◦328◦−5◦
Apr 30 232◦−19◦279◦+34◦332◦−3◦ELY
May 05 237◦−20◦337◦−1◦283◦+44◦
May 10 242◦−21◦341◦+1◦288◦+44◦
May 15 247◦−22◦345◦+3◦293◦+45◦
May 20 252◦−22◦349◦+5◦
May 25 256◦−23◦353◦+7◦
May 30 262◦−23◦ARI
Jun 5 267◦−23◦42◦+24◦
Jun 10 272◦−23◦47◦+24◦
Jun 15 276◦−23◦
Jun 20 281◦−23◦JBO
Jun 25 286◦−22◦223◦+48◦
Jun 30 291◦−21◦225◦+47◦CAP
Jul 5 296◦−20◦285◦−16◦SDA
Jul 10 300◦−19◦PER 289◦−15◦325◦−19◦PAU
Jul 15 305◦−18◦6◦+50◦294◦−14◦329◦−19◦330◦−34◦
Jul 20 310◦−17◦11◦+52◦299◦−12◦333◦−18◦334◦−33◦
Jul 25 315◦−15◦22◦+53◦303◦−11◦337◦−17◦338◦−31◦
Jul 30 319◦−14◦29◦+54◦307◦−10◦340◦−16◦343◦−29◦KCG
Aug 5 325◦−12◦37◦+56◦313◦−8◦345◦−14◦348◦−27◦283◦+58◦
Aug 10 330◦−10◦45◦+57◦318◦−6◦349◦−13◦352◦−26◦284◦+58◦
Aug 15 335◦−8◦51◦+58◦352◦−12◦285◦+59◦
Aug 20 340◦−7◦57◦+58◦AUR 356◦−11◦286◦+59◦
Aug 25 344◦−5◦63◦+58◦85◦+40◦288◦+60◦
Aug 30 349◦−3◦90◦+39◦SPE CCY 289◦+60◦
Sep 5 355◦−1◦STA 96◦+39◦43◦+40◦293◦+29◦
Sep 10 0◦+1◦12◦+3◦102◦+39◦48◦+40◦297◦+30◦
Sep 15 15◦+4◦53◦+40◦301◦+31◦
Sep 20 18◦+5◦DSX 59◦+41◦305◦+32◦
Sep 25 21◦+6◦150◦0◦309◦+33◦
Sep 30 25◦+7◦155◦0◦ORI OCT
Oct 5 28◦+8◦85◦+14◦DAU 164◦+79◦DRA
Oct 10 32◦+9◦EGE 88◦+15◦82◦+45◦262◦+54◦
Oct 15 NTA 36◦+11◦99◦+27◦91◦+15◦87◦+43◦LMI
Oct 20 38◦+18◦40◦+12◦104◦+27◦94◦+16◦92◦+41◦158◦+39◦
Oct 25 43◦+19◦43◦+13◦109◦+27◦98◦+16◦163◦+37◦
Oct 30 47◦+20◦47◦+14◦101◦+16◦168◦+35◦
Nov 5 52◦+21◦52◦+15◦105◦+17◦LEO
Nov 10 56◦+22◦56◦+15◦NOO 147◦+24◦AMO
Nov 15 61◦+23◦60◦+16◦81◦+16◦150◦+23◦112◦+2◦
Nov 20 65◦+24◦64◦+16◦84◦+16◦153◦+21◦116◦+1◦
Nov 25 70◦+24◦88◦+16◦PHO 156◦+20◦PUP 120◦0◦
Nov 30 74◦+24◦GEM 92◦+16◦14◦−52◦159◦+19◦120◦−45◦91◦+8◦
Dec 5 85◦+23◦103◦+33◦149◦+37◦18◦−53◦122◦+3◦122◦−45◦98◦+9◦
Dec 10 90◦+23◦108◦+33◦153◦+35◦22◦−53◦126◦+2◦125◦−45◦101◦+8◦
Dec 15 96◦+23◦113◦+33◦157◦+33◦174◦+19◦130◦+1◦128◦−45◦105◦+7◦
Dec 20 101◦+23◦118◦+32◦161◦+31◦177◦+18◦134◦0◦217◦+76◦108◦+7◦
Dec 25 106◦+22◦166◦+28◦180◦+16◦HYD 217◦+74◦MON
Dec 30 111◦+21◦226◦+50◦170◦+26◦COM URS
ANT QUA DLM
IMO INFO(2-19) 27
Table 6a. Radiant positions during the year in αand δfor the sources of possible
activity described in the text.
Shower Activity λ⊙Radiant
(or parent) Date 2000 α δ
κ-Cancrids (793 KCA) Jan 10 289 .
◦315 138◦+9◦
α-Virginids (021 AVB) Apr 24 34 .
◦273 198◦+7◦
461852 (τHer) May 14 54 .
◦279 248◦+46◦
July γ-Draconids (184 GDR) Jul 28 125 .
◦132 280◦+51◦
β-Hydrusids Aug 16 143 .
◦886 23◦−76◦
2015 TB145 (νEri) Oct 20 217 .
◦659 64◦−3◦
2001XQ (66 Draconids) Dec 04 252 .
◦26 314◦+60◦
Table 7. Working List of Daytime Radio Meteor Showers. According to the naming
rules, the shower names should all have ‘Daytime’ added (it is omitted in this Table). An asterisk
(‘*’) in the ‘Max date’ column indicates that source may have additional peak times, as noted
in the text above. See also the details given for the Arietids (171 ARI) and the Sextantids
(221 DSX) in the text part of the Calendar. Rates are expected to be low (L), medium (M) or
high (H). An asterisk in the ‘Rate’ column shows the suggested rate may not recur in all years.
Thanks to Chris Steyaert for comments on the data compiled in this Table.
Shower Activity Max λ⊙Radiant Rate
Date 2000 α δ
Capricornids/Sagittariids (115 DCS) Jan 13–Feb 04 Feb 01∗312 .
◦5 299◦−15◦M∗
χ-Capricornids (114 DXC) Jan 29–Feb 28 Feb 14∗324 .
◦7 315◦−24◦L∗
April Piscids (144 APS) Apr 20–Apr 26 Apr 22 32 .
◦5 9◦+11◦L
ε-Arietids (154 DEA) Apr 24–May 27 May 09 48 .
◦7 44◦+21◦L
May Arietids (294 DMA) May 04–Jun 06 May 16 55 .
◦5 37◦+18◦L
o-Cetids (293 DCE) May 05–Jun 02 May 20 59 .
◦3 28◦−04◦M∗
Arietids (171 ARI) May 14–Jun 24 Jun 07 76 .
◦6 42◦+25◦H
ζ-Perseids (172 ZPE) May 20–Jul 05 Jun 09∗78 .
◦6 62◦+23◦H
β-Taurids (173 BTA) Jun 05–Jul 17 Jun 28 96 .
◦7 86◦+19◦M
γ-Leonids (203 GLE) Aug 14–Sep 12 Aug 25 152 .
◦2 155◦+20◦L∗
Sextantids (221 DSX) Sep 09–Oct 09 Sep 27∗184 .
◦3 152◦0◦M∗
28 IMO INFO(2-19)
10 Useful addresses
On the IMO’s website http://www.imo.net you find online forms to submit visual reports and
reports of fireball sightings. It is also possible to submit reports of visual observation sessions
for other observers. You can also access all reports in the database, both of visual data and
fireball reports.
Visual reports: http://www.imo.net →Observations →Add a visual observation session
Fireball reports: http://www.imo.net →Observations →Report a fireball
For more information on observing techniques, to see the latest results from well-observed major
meteor showers and unusual shower outbursts, or when you wish to submit your results, please
use the IMO’s website, www.imo.net as your first stop. The web page also allows to access
the data for own analyses. Questions can be mailed to the appropriate address (note the word
“meteor” must feature in your message’s “subject” line to pass the anti-spam filters):
For especially bright meteors: fireball@imo.net
For meteor still imaging: photo@imo.net
For forward-scatter radio observing: radio@imo.net
For meteor moving-imaging: video@imo.net
For visual observing: visual@imo.net
The IMO has Commssions for various fields, about which you may enquire with the respective
director:
Photographic Commission: William Ward, School of Engineering, Rankine Building, Oak-
field Avenue, Glasgow G12 8LT, Scotland, U.K.; e-mail: William.Ward@glasgow.ac.uk
Radio Commission: Jean-Louis Rault, Soci´et´e Astronomique de France, 16 Rue de la Valle´e,
F-91360 Epinay sur Orge, France; e-mail: f6agr@orange.fr
Video Commission Sirko Molau, Abenstalstraße 13b, D-84072 Seysdorf, Germany;
e-mail: sirko@molau.de
Visual Commission: Rainer Arlt, Leibniz-Institut f. Astrophysik, An der Sternwarte 16,
D-14482 Potsdam, Germany; e-mail: rarlt@aip.de
You can join the International Meteor Organization by visiting the web page www.imo.net →
“Join the IMO”.
As an alternative or to obtain additional information, you may contact the Secretary-General
via lunro.imo.usa@cox.net.
Those unable to access the Internet may write for information to Robert Lunsford, IMO Secretary-
General, 14884 Quail Valley Way, El Cajon, CA 92021-2227, USA. When using ordinary mail,
please try to enclose return postage, either in the form of stamps (same country only) or as an
International Reply Coupon (I.R.C. – available from main postal outlets). Thank you!
c International Meteor Organization, 2019.
