October to December 2004

New Moon in these three months falls such that observations of
13 of the 15 meteor showers with potential maxima can receive
some useful coverage at least. The two which lose out as too
near full Moon are the chi-Orionids (maximum on December 1) and
the Ursids (peak due on December 22, most likely near 7h UT,
but possibly up to two hours or so later).

---

Draconids

  
  Active  : October 6-10;  
  Maximum  : October 8, 10h UT, (sol = 195.4°, but see below);  
  ZHR   = periodic, up to storm levels;  
  Radiant  : alpha = 262°, delta = +54°;  
  Radiant drift: negligible;  
  V   = 20 km/s;  
  r   = 2.6;  
  TFC   : alpha = 290°, delta = +65° and  
      alpha = 288°, delta = +39° (beta>30° N).  
   
  

Figure 13: Radiant position of the Draconids

The Draconids are primarily a periodic shower which produced
spectacular, brief, meteor storms twice last century, in 1933
and 1946, and lower rates in several other years (ZHRs
20-500+), most recently in 1998 (when EZHRs briefly reached
700). Most detected showers were in years when the stream's
parent comet, 21P/Giacobini-Zinner, returned to perihelion, as
last in 1998 November. The next return of the comet is in mid
2005. The 1998 outburst happened at sol = 195.07°, equivalent
to 2004 October 8, 2h 10m UT, although the nodal crossing
time used above, close to sol = 195.4°, may be more generally
applicable. In 1999 an unexpected minor visual-radio outburst
(ZHRs 10-20) occurred over the Far East between sol =
195.63°-195.76°. A repeat at this time would be on 2004
October 8, 15h 40m – 18h 50m UT. The radiant is circumpolar
from many northern hemisphere locations, but is higher in the
pre-midnight and near-dawn hours in early October. The waning
crescent Moon makes this a good year to see what the shower
yields – even if this is nothing detectable. Draconid meteors
are exceptionally slow-moving, a characteristic which helps
separate genuine shower meteors from sporadics accidentally
lining up with the radiant.

---

epsilon-Geminids

  
  Active  : October 14-27;  
  Maximum  : October 18, (sol = 205°);  
  ZHR   = 2;  
  Radiant  : alpha = 102°, delta = +27°;  
  Radiant drift: see Table 6;  
  V   = 70 km/s;  
  r   = 3.0;  
  TFC   : alpha = 90°, delta = +20° and  
      alpha = 125°, delta = +20° (beta>20° S).  
  

A weak minor shower with characteristics and activity nearly
coincident with the Orionids, so great care must be taken to
separate the two sources by instrumental techniques – especially
video or telescopic work – or visual plotting. The early-setting
waxing crescent Moon on October 18 presents an excellent
opportunity to obtain more data on them from either hemisphere,
although northern observers have an advantage, and can usefully
access the radiant from about midnight onwards.

---

Orionids

  
  Active  : October 2 - November 7;  
  Maximum  : October 21 (sol = 208°);  
  ZHR   = 23;  
  Radiant  : alpha = 95°, delta = +16°;  
  Radiant drift: see Table 6;  
  V   = 66 km/s;  
  r   = 2.5;  
  TFC   : alpha = 100°, delta = +39° and  
      alpha = 75°, delta = +24° (beta>40° N); or  
      alpha = 80°, delta = +1° and  
      alpha = 117°, delta = +1° (beta<40° N).  
   
  

Figure 14: Radiant position and drift of the Orionids and epsilon-Geminids

October's waxing gibbous Moon favours the Orionids on October
20/21, as it will be setting – or indeed have long set for the
northern hemisphere – by the time the radiant is at a useful
elevation (around local midnight in either hemisphere, somewhat
before in the north). Most of the globe can enjoy the shower, as
the radiant is quite near the celestial equator. Audrius
Dubietis carried out an analysis of the shower in IMO data
from 1984-2001 in early 2003, which has allowed some minor
modifications to the peak ZHR and r parameters above. Both
these aspects were also shown to vary somewhat from year to
year, the maximum mean ZHR especially ranging from 14-31 during
the last two decades. In addition, a suspected 12-year
periodicity in higher returns found earlier in the 20th century
appears to have been partly confirmed, which may mean stronger
returns in 2008-2010. The Orionids were always noted for having
several lesser maxima other than the main one above, helping
activity sometimes to remain roughly constant for several
consecutive nights centred on this peak. In 1993 and 1998, a
submaximum about as strong as the normal peak was detected on
October 17/18 from Europe, for instance. All observers should be
aware of these possibilities, as observing circumstances are
very favourable for covering October 17/18 in dark skies this
year. Several subradiants have been reported in the past, but
recent video work suggests the radiant is far less complex;
photographic, telescopic and video work to confirm this would be
useful, as visual observers have clearly had problems with this
shower's radiant determination before.

---

Taurids

Southern Taurids

  
  Active  : October 1-November 25;  
  Maximum  : November 5 (sol = 223°);  
  ZHR   = 5;  
  Radiant  : alpha = 052°, delta = +13°;  
  Radiant drift: see Table 3;  
  V   = 27 km/s;  
  r   = 2.3;  
  TFC   : Choose fields on the ecliptic and about 10° E or W of the  
      radiants (beta>40° S).  
   
  

Northern Taurids

  
  Active  : October 1-November 25;  
  Maximum  : November 12 (sol = 230°);  
  ZHR   = 5;  
  Radiant  : alpha = 058°, delta = +22°;  
  Radiant drift: see Table 3;  
  V   = 29 km/s;  
  r   = 2.3;  
  TFC   : as Southern Taurids.  
   
  

Figure 15: Radiant position and drift of the Northern and Southern Taurids

These two streams form part of the complex associated with Comet
2P/Encke. Defining their radiants is best achieved by careful
visual or telescopic plotting, photography or video work, since
they are large and diffuse. They are currently being studied
using IMO data by Mihaela Triglav. The brightness and
relative slowness of many shower meteors makes them ideal
targets for photography, while these factors coupled with low,
steady, combined Taurid rates makes them excellent targets for
newcomers to practice their plotting techniques on. The activity
of both streams produces an apparently plateau-like maximum for
about ten days in early November, and the showers have a
reputation for producing some excellently bright fireballs at
times, although seemingly not in every year. David Asher has
indicated that increased Taurid fireball rates may result from a
“swarm” of larger particles within the Taurid stream complex,
and he suggested such “swarm” returns might happen in 1995 and
1998 most recently. In 1995, an impressive crop of bright
Taurids occurred between late October to mid November, while in
1998, Taurid ZHRs reached levels comparable to the usual maximum
rates in late October, together with an increased flux of
brighter Taurids generally. The next potential October-November
“swarm” return is not predicted until 2005, but we cannot be
sure how correct this is as yet. Unfortunately, full Moon ruins
this period in 2004, but this does mean a last quarter waning to
new Moon for the regular early November maxima.

The near-ecliptic radiants for both shower branches mean all
meteoricists can observe the streams. Northern hemisphere
observers are somewhat better-placed, as here suitable radiant
zenith distances persist for much of the late autumnal nights.
Even in the southern hemisphere, a good 3-5 hours' watching
around local midnight is possible with Taurus well above the
horizon, however.

---

Leonids

  
  Active  : November 14-21;  
  Maximum  : November 17, 8h 25mUT (sol = 235.27°);  
  ZHR   = 10-50+  
  Radiant  : alpha = 153°, delta = +22°;  
  Radiant drift: see Table 6;  
  V   = 71 km/s;  
  r   = 2.9;  
  TFC   : alpha = 140°, delta = +35° and  
      alpha = 129°, delta = +6° (beta>35° N); or  
      alpha = 156°, delta = -3° and  
      alpha = 129°, delta = +6° (beta<35° N);  
  PFC   : before 00h local time alpha = 120°, delta = +40° (beta>40° N);  
      before 04h local time alpha = 120°, delta = +20° (beta>0° N);  
     and after 04h local time alpha = 160°, delta = 0° (beta>0° N);  
      before 04h local time alpha = 120°, delta = +10° (beta<0° N)  
     and after 04h local time alpha = 160°, delta = -10° (beta<0° N).  
  

Figure 16: Radiant position and drift of the Leonids

In theory, the ending of the strong to storm Leonid returns
between 1998-2002 associated with particles accompanying the shower's
parent comet, 55P/Tempel-Tuttle, which had returned to its
perihelion in 1998, should mean 2004
will see a continuing decline in activity back towards its
earlier ZHRs of 10-15. Certainly, no enhanced activity is
predicted, although as meteor enthusiasts know well, surprises
can occur from even the best-known showers on occasion!
Observers should be alert to covering whatever the shower
produces, as following the post-storm phases after this
best-ever observed run of storm returns is as vital to our
understanding of the stream as seeing the storms themselves. The
Leonid radiant rises usefully only around local midnight (or
indeed afterwards south of the equator), splendid news, as the
waxing crescent Moon will have set long before this time on
November 16/17. If the peak occurs close to the nodal crossing
time above, it will favour sites across the Americas, but other
peak times cannot be excluded, and observers should be watching
as often as conditions allow throughout the shower, in case
something unexpected happens. All observing techniques can be
usefully employed.

---

alpha-Monocerotids

  
  Active  : November 15-25;  
  Maximum  : November 21, 8h 45m UT (sol = 239.32°);  
  ZHR   = variable, usually around 5 but may produce outbursts to around 400+;  
  Radiant  : alpha = 117°, delta = +1°;  
  Radiant drift: see Table 6;  
  V   = 65 km/s;  
  r   = 2.4;  
  TFC   : alpha = 115°, delta = +23° and  
      alpha = 129°, delta = +20° (beta>20° N); or  
      alpha = 110°, delta = -27° and  
      alpha = 98°, delta = +6° (beta<20° N);  
   
  

Figure 17: Radiant position and drift of the alpha-Monocerotids

Another late-year shower capable of producing surprises, the
alpha-Monocerotids gave their most recent brief outburst in
1995 (the top EZHR, 420, lasted just five minutes; the entire
outburst 30 minutes). Many observers across Europe witnessed it,
and we have been able to completely update the known shower
parameters as a result. Whether this indicates the proposed
ten-year periodicity in such returns is real or not, only the
future will tell (next year!), so all observers should continue
to monitor this source closely. The waxing gibbous Moon on
November 20/21 will have set by 1h-2h local time across much
of the world, so observing is eminently practical, because the
radiant is well on view from either hemisphere after about 23h
local time. The expected peak falls especially well for sites in
the Americas, except for the more easterly parts of South
America.

---

Phoenicids

  
  Active  : November 28-December 9;  
  Maximum  : December 6, 2h 35mUT (sol = 254.25°);  
  ZHR   = variable, usually 3 or less, may reach 100;  
  Radiant  : alpha = 018°, delta = -53°;  
  Radiant drift: see Table 6;  
  V   = 18 km/s;  
  r   = 2.8;  
  TFC   : alpha = 040°, delta = -39° and  
      alpha = 065°, delta = -62° (beta<10° N).  
   
  

Figure 18: Radiant position and drift of the Phoenicids

Only one impressive Phoenicid return has so far been reported,
that of its discovery in 1956, when the ZHR was 100. Three
other potential bursts of lower activity have been reported, but
never by more than one observer, under uncertain circumstances.
Reliable IMO data shows recent activity to be virtually
nonexistent. This may be a periodic shower however, and more
observations of it are needed by all methods. Radio workers may
find difficulties, as radar echoes from the 1956 event were only
30 per hour, perhaps because these low-velocity meteors produce
too little radio-reflecting ionization. Observing conditions for
all southern hemisphere watchers are moderate, with last quarter
Moon rising only around 1h local time on December 5/6, while
the radiant culminates at dusk, remaining well on view for most
of the night.

---

Puppid-Velids

  
  Active  : December 1-December 15;  
  Maximum  : December 6 (sol = 255°);  
  ZHR   = about 10;  
  Radiant  : alpha = 123°, delta = -45°;  
  Radiant drift: see Table 3;  
  V   = 40 km/s;  
  r   = 2.9;  
  TFC   : alpha = 090° to 150°, delta = -20° to -60°;  
      choose pairs of fields separated by about 30° in alpha, moving  
      eastwards as the shower progresses (beta<10° N).  
  

This is a very complex system of poorly-studied showers, visible
chiefly to those south of the equator. Up to ten sub-streams
have been identified, with radiants so tightly clustered, visual
observing cannot readily separate them. Photographic, video or
telescopic work would thus be sensible, or very careful visual
plotting. The activity is so badly known, we can only be
reasonably sure that the highest rates occur in early to mid
December, coincident with a waning Moon this year. Some of these
showers may be visible from late October to late January. Most
Puppid-Velid meteors are quite faint, but occasional bright
fireballs, notably around the suggested maximum here, have been
reported previously. The radiant area is on-view all night, but
is highest towards dawn.

---

Monocerotids

  
  Active  : November 27-December 17;  
  Maximum  : December 8 (sol = 257°);  
  ZHR   = 3;  
  Radiant  : alpha = 100°, delta = +8°;  
  Radiant drift: see Table 6;  
  V   = 42 km/s;  
  r   = 3.0;  
  TFC   : alpha = 088°, delta = +20° and  
      alpha = 135°, delta = +48° (beta>40° N); or  
      alpha = 120°, delta = -03° and  
      alpha = 84°, delta = +10° (beta<40° N);  
  

Only low visual rates are likely from this minor source, making
accurate visual plotting, telescopic or video work essential,
particularly because the meteors are normally faint. The
shower's details, even including its radiant position, are
rather uncertain. Recent IMO data show only weak signs of
a maximum as indicated above. Telescopic results suggest a later
maximum, around December 16 (sol 264°) from a radiant at
alpha = 117°, delta = +20°. This is a reasonable year for
making observations, as the waning crescent Moon rises by
2h-3h local time for all observers on December 8, while the
radiant is on-show virtually all night, culminating about
1h 30m local time.

---

sigma-Hydrids

  
  Active  : December 03-15;  
  Maximum  : December 11 (sol = 260°);  
  ZHR    = 2;  
  Radiant  : alpha=127°, delta=+02°;  
  Radiant drift: see Table 6;  
  V    = 58 km/s;  
  r    = 3.0;  
  TFC   : alpha=095°, delta=00° and alpha=160°, delta=00°  
      (all sites, after midnight only).  
   
  

Figure 19: Radiant position and drift of the sigma-Hydrids

Although first detected in the 1960s by photography,
sigma-Hydrids are typically swift and faint, and rates are
generally very low, close to the visual detection threshold.
Since their radiant, a little over 10° east of the star
Procyon (alpha Canis Minoris), is near the equator, all
observers can cover this shower. The radiant rises in the late
evening hours, but is best viewed after local midnight. New Moon
creates a perfect viewing opportunity for the peak date given
above this year. Recent data indicates the maximum may happen up
to six days earlier than this, which would be much less
favourable for Moon-free watching. The shower would benefit from
visual plotting, telescopic or video work to pin it down more
accurately.

---

Geminids

  
  Active  : December 7-17;  
  Maximum  : December 13, 22h 20m UT (sol = 262.2°) +/- 2.3h;  
  ZHR   = 120;  
  Radiant  : alpha = 112°, delta = +33°;  
  Radiant drift: see Table 6;  
  V   = 35 km/s;  
  r   = 2.6;  
  TFC   : alpha = 87°, delta = +20° and  
      alpha = 135°, delta = +49°; before 23h local time,  
      alpha = 87°, delta = +20° and  
      alpha = 129°, delta = +20° after 23h local time (beta>40° N);  
      alpha = 120°, delta = -3° and  
      alpha = 84°, delta = +10° (beta<20° N);  
  PFC   : alpha = 150°, delta = +20° and  
      alpha = 60°, delta = +40° (beta>20° N);  
     and alpha = 135°, delta = -5° and  
      alpha = 80°, delta = 0° (beta<20° N)  
   
  

Figure 20: Radiant position and drift of the Geminids and Monocerotids

One of the finest annual showers presently observable. This
year, new Moon on December 12 gives perfect observing conditions
across the expected maximum on December 13/14. The Geminid
radiant culminates around 2h local time. Well north of the
equator, the radiant rises around sunset, and is at a usable
elevation from the local evening hours onwards. In the southern
hemisphere, the radiant appears only around local midnight or
so. Even here, this is a splendid shower of often bright,
medium-speed meteors, a rewarding sight for all watchers. The
peak has shown slight signs of variability in its maximum rates
and peak timing in recent years, with the six most reliably
observed maxima over the past 15 years having all occurred
within 2h 20m of the time above. The main predicted timing
favours European and North African locations eastwards to
central Russian and Chinese longitudes. An earlier or later
timing would extend this best-visible zone some way eastwards or
westwards respectively. Some mass-sorting within the stream
means the fainter telescopic meteors should be most abundant
almost 1° of solar longitude (about one day) ahead of the
visual maximum, with telescopic results indicating these meteors
radiate from an elongated region, perhaps with three
sub-centers. Further results on this topic would be useful, but
all methods can be employed to observe the shower.

---

Coma Berenicids

  
  Active  : December 12 - January 23;  
  Maximum  : December 19, (sol = 268°);  
  ZHR   = 5;  
  Radiant  : alpha = 175°, delta = +25°;  
  Radiant drift: see Table 6;  
  V   = 65 km/s;  
  r   = 3.0;  
  TFC   : alpha = 180°, delta = +50° and  
      alpha = 165°, delta = +20° before 03h local time; or  
      alpha = 195°, delta = +10° and  
      alpha = 200°, delta = +45° after 03h local time (beta>20° N).  
   
  

Figure 21: Radiant position and drift of the Coma Berenicids

A weak minor shower that is usually observed only during the
Geminid and Quadrantid epochs, but which needs more coverage at
other times too, especially to better-define its maximum. The
shower is almost unobservable from the southern hemisphere, so
northern watchers must brave the winter cold to improve our
knowledge of it. The radiant is at a useful elevation from local
midnight onwards, conveniently after waxing gibbous moonset in
2004.