January to March 2004

For the major showers, the year begins with a very poor
northern-hemisphere Quadrantid return (the waxing gibbous Moon
is above the horizon almost all night near the maximum, around
6h UT on January 4), and the southern-hemisphere
alpha-Centaurids are even worse (peak due around 16h 40m UT
on February 8; full Moon is on February 6!). The minor
delta-Cancrids and delta-Leonids are significantly
better-placed. The diffuse ecliptical stream complex of the
Virginids gets underway by late January, running through to mid
April, probably producing several low, and poorly observed,
maxima in March or early April. The interesting late January to
early February spell, during which several new minor showers
have been suggested in recent years, is almost entirely
Moon-free, especially for most of the, perhaps core, January 20-27
period. Check your plots for potential swift-meteor
radiants in the Coma-Leo-Virgo area and its surrounds
particularly. Mid-March sees the southern-hemisphere
gamma-Normids lose out to last quarter Moon for their possible
maximum on March 13, though recent results imply a later peak
around March 17 may occur now (rather more favourable for
checking). The shower's details are most uncertain, with ZHRs
virtually undetectable more than a day or two away from the
peak, whenever – or even if – it happens. Daylight radio shower
peaks are theoretically due from the Capricornids/Sagittarids
around February 2, 2h UT, and the chi-Capricornids on
February 14, 3h UT. Recent radio results suggest the Cap/Sgr
maximum may variably fall up to 2 or 3 days later than this
however, while activity near the expected chi-Capricornid peak
has tended to be slight and perhaps a day or so later in
1999-2001. Both showers have radiants <10°-15° west of the
Sun at maximum, so cannot be regarded as visual targets even
from the southern hemisphere.

delta-Cancrids

  
  Active  : January 1-24;  
  Maximum  : January 17 (sol = 297°);  
  ZHR   = 4;  
  Radiant  : alpha = 130°, delta = +20°;  
  Radiant drift: see Table 3;  
  V   = 28 km/s;  
  r   = 3.0;  
  TFC   : alpha = 115°, delta = +24° and  
      alpha = 140°, delta = +35° (beta>40° N);  
      alpha = 120°, delta = -03° and  
      alpha = 140°, delta = -03° (beta<40° N).  
   
  
  
  Figure 1: Radiant position and drift of the delta-Cancdrids

This minor shower of predominantly faint meteors is well-suited
to telescopic observations, with a large, complex, diffuse
radiant that probably consists of several sub-centers. Visual
observers should assume a minimum radiant size of roughly 20°
in alpha by 10° in delta about the radiant point given
above. This type of large, loose radiant area is similar to the
Virginids, and the delta-Cancrids are probably an early part of
the Virginid activity. Recent observations have suggested the
peak may occur close to sol = 291° (2004 January 11), though
ZHRs do not rise above 3-4 even then. Last quarter Moon on
January 15 means only the January 17 peak time will be
observably moonless, and watches to see what occurs near this
date should definitely be attempted. The long northern winter
nights are ideal for making observations, while the radiant is
above the horizon almost all night in either hemisphere.

---

delta-Leonids

  
  Active  : February 15 - March 10;  
  Maximum  : February 25 (sol = 336°);  
  ZHR   = 2;  
  Radiant  : alpha = 168°, delta = +16°;  
  Radiant drift: see Table 6;  
  V   = 23 km/s;  
  r   = 3.0;  
  TFC   : alpha = 140°, delta = +37° and  
      alpha = 151°, delta = +22° (beta>10° N);  
      alpha = 140°, delta = -10° and  
      alpha = 160°, delta = 0° (beta<10° N).  
   
  
  
  Figure 2: Radiant position and drift of the delta-Leonids

Like the delta-Cancrids, this minor shower may
appear to be part of the Virginid activity but it
has a radiant clearly north of the ecliptic and is probably
associated with an asteroid, (4450) Pan. Rates are normally low, and
its meteors are predominantly faint, so it is a prime candidate
for telescopic investigation. Visual observers must make very
accurate plots of the meteors to distinguish them from the
nearby Virginids and the sporadics. Northern hemisphere sites
have an advantage for covering this shower, but southern
hemisphere watchers should not ignore it, as they are
better-placed to note many of the other Virginid radiants. On
February 25, the waxing crescent Moon sets between about
23h-0h local time for typical northern sites, and before
22h for the mid-southern hemisphere. The radiant is well on
view for most of the night near its peak.