The moon will reach its full phase on Wednesday November 20. At this time it rises near sunset and will be in the sky most of the night. The moon will set earlier in the period allowing a small window of opportunity to view during the dark late morning hours. The estimated total hourly rates for evening observers this week should be near 2 for those in the Northern Hemisphere and 1 for those south of the equator. Moonlight will interfere with evening observing this week. For morning observers the estimated total hourly rates should be near 25 for those located in the Northern Hemisphere and 15 for those located in the Southern Hemisphere. These rates assume that you are watching from rural areas away from all sources of light pollution. The actual activity one may see will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity.
The positions
listed below are exact for Saturday night/Sunday morning November 16/17.
The positions do not change greatly day to day so these positions may be
used during this entire period. Most star atlases (available at science stores
and libraries) will provide maps with grid lines of the celestial coordinates
so that you may find out exactly where these positions are located in the
sky. A planisphere or computer planetarium program is also useful in showing
which constellations are in the sky at any time of night on any date of the
year. Activity from each radiant is best seen when it is positioned highest
in the sky, either due north or south along the meridian, depending on your
location. Meteor activity is not seen from radiants that are located below
the horizon. The radiants below are listed in a west to east manner in order
of right ascension (celestial longitude). The radiants listed first are located
further west therefore are accessible earlier in the night. This list also
provides the order of ascending velocity for each radiant with those listed
first usually being much slower than those last on the list. Velocity should
not be the prime factor for shower association as all showers can produce
slow meteors. Slow meteors can be produced from normally swift showers, such
as the Leonids, when meteors appear near the radiant or close to the horizon.
The true velocity is only revealed in shower members seen far from the radiant
and high in the sky.
The Delta Eridanids are listed among the radiants of the Dutch Meteor Society. This shower peaked on November 12 with a ZHR of only 1. At these rates this shower would be extremely difficult to distinguish from the high sporadic rates seen this time of year. The radiant is located at 04:00 (060) –01 which places it in a remote area of northern Eridanus near the 4th magnitude star 35 Eridani. The radiant is best placed near midnight local time, when it lies highest in the sky. With an entry velocity of 31 km/sec., these meteors would appear to travel slower than your average meteor.
The Antihelion radiant is now located at 04:40 (070) +22. This area of the sky is located in central Taurus, 2 degrees south of the 4th magnitude star Tau Tauri. Any slow to medium speed meteor from Taurus could be a candidate for this shower. The radiant is best placed near 0100 local standard time when it lies on the meridian and is highest in the sky. We are now starting to see an increase in the antihelion activity as the Earth encounters debris from comet 1P Encke in addition to the normal material. At this time expect to see 5 shower members per hour from areas north of the equator and 3 per hour for locations south of the equator.
Unlike
most of the annual showers the antihelion radiant is produced by debris from
unknown sources orbiting in a direct motion like the earth. These sources
are most likely asteroids, which produce stony and metallic debris whose
density is much greater than material produced by comets. This debris collides
with the earth on the inbound portion of its orbit, before its closest approach
to the sun. Therefore we best see them just after midnight when we are facing
the direction from which this activity appears. The antihelion radiant is
active all year from an area of the sky nearly opposite that of the sun.
The radiant will travel approximately one degree eastward per day and travels
through many different constellations over the course of a year. It is easiest
to simply list these meteors as "ANT" but a majority of meteor organizations
prefer that you list them from the constellation in which the radiant is
currently located or the constellation where the shower reaches maximum activity.
IMO observers may wish to list these meteors as Taurids or "STA or
NTA's" depending on whether the meteors radiate from north or south of
the ecliptic.
The Zeta
Puppids are another shower listed among the radiants of the Dutch Meteor
Society. This shower peaked on November 13 with a ZHR of only 3. The radiant
is located at 08:00 (120) -43. This position lies in the star rich field
of central Puppis, 3 degrees south of the 2nd magnitude star Zeta Puppis.
These meteors are best seen near 0400 local standard time when the radiant
lies highest above the horizon in a dark sky. At 41 km/sec. the Zeta Puppids
produce meteors of average velocity.
The Northern Apex radiant is now located at 09:40 (145) +28. This position lies in northwestern Leo 4 degrees north of the 3rd magnitude star Epsilon Leonis. This area of the sky is best placed for viewing during the last dark hour before dawn. Since this radiant is diffuse any meteors from Leo Minor, Leo or northern Cancer could be a good candidate for this shower. This source should provide at least 3 meteors per hour for those in the Northern Hemisphere and less than 1 per hour for those in the Southern Hemisphere. These meteors will most likely be lost in the surging Leonid activity this week. These meteors are very similar to Leonids are now radiate less than 10 degrees from the true Leonid radiant.
Like the antihelion radiant both apex radiants are active all year long and travel approximately one degree eastward per day. Unlike the antihelion debris these particles orbit the sun in a retrograde motion opposite that of the earth and are most likely produced by unknown comets. They strike the earth after their closest approach to the sun. Since they are moving in opposite directions these particles strike the earth at tremendous velocities often creating bright meteors with persistent trains. These particles strike the earth on the morning side of earth and are best seen just before morning twilight while the sky is still perfectly dark. There are meteors with a zero inclination that radiate precisely from the apex point on the ecliptic, exactly 90 degrees west of the sun. These meteors are rare though as the earth orbits the sun it "sweeps clean" much of the material that shares the same orbit. Much more debris is located just north and south of the earth's orbit with slightly higher or lower inclinations. This creates the northern and southern branches of the apex activity. Meteors from both branches are normally included in the sporadic count but should also be noted in some manner as to which branch of the apex complex they appear to radiate.
The Southern Apex source lies exactly 30 degrees south of its northern counterpart at 09:40 (145) -02. This position lies in western Hydra very close to the 4th magnitude star Iota Hydrae. Like the northern apex, these meteors are best seen toward dawn when the radiant lies highest above the horizon in a dark sky. Any meteor from western Hydra could a candidate from this source. Rates would be now close to 2 per hour regardless of your location.
The Leonids peak on Tuesday morning Nov. 19 from a radiant located at 10:12 (153) +22. This position lies in western Leo within the "sickle" of Leo. This is also only 2 degrees northwest of the famous double star Algeiba (Gamma Leonis). The radiant rises between late evening and early morning depending on your latitude. It rises earlier the further north one lives. There are two outbursts of the Leonids predicted to occur this year. The first one occurs near 0400 UT on November 19. For North American longitudes this corresponds to 1100 pm EST and 0800pm PST on the evening of November 18. This is too early to be see from the great majority of North America. Europe and northwestern Africa are ideally situated to view this outburst. The second outburst is predicted to occur near 1040 UT. Extreme northeastern South America, Central America and North America are favored for this second outburst. Unfortunately the western Pacific, Asia, Australia and most of Africa will miss the best portion of the show. With the full moon in the western sky many of the fainter Leonids will be lost in the moon's glare. Therefore it will be difficult to predict the strength of this years display. If it is anything remotely similar to the 2001 display then it would be well worth watching despite the intense moonlight. At 71 km/sec., the Leonids are among the swiftest of meteors. Those seen near the radiant will appear slower since they are approaching the observer. If it's clear don't miss this display as it is predicted to be the last Leonid storm and perhaps the last meteor storm until 2099.
The Sporadic rates for the Northern Hemisphere have now reached their plateau of top activity, which occurs during the entire last quarter of the year. One would currently expect to see perhaps 10 random meteors per hour during the last hours before dawn from rural observing sites. This estimate and the morning estimate for the Southern Hemisphere does not include the apex meteors listed above. During the evening hours perhaps 4 random meteors can be seen per hour from the Northern Hemisphere. Rates seen from the Southern Hemisphere are now at their annual low with perhaps 5 random meteors being seen per hour during the early morning hours and 2 per hour during the evening. Moonlight will reduce sporadic rates seen in the evening sky this week.
Clear Skies!