(meteorobs) Meteor Activity Outlook for October 9-15, 2010

[Robert Lunsford]

Meteor activity in general increases in October when compared to September.
A major shower (the Orionids) is active most of the month along with several
minor showers. Both branches of the Taurids become more active as the month
progresses, providing slow, graceful meteors to the nighttime scene. The
Orionids are usually the big story of the month but this year the Orionid
peak coincides with the full moon. Orionid activity can be seen before and
after maximum when the moon is not so troublesome. Unfortunately Orionid
rates will be low, most likely less than five per hour.

During this period the moon reaches its first quarter phase on Thursday
October 14th. At this time the moon will be located ninety degrees east of
the sun and will set near 0100 local daylight time (LDT) for those living in
the mid-northern latitudes. This weekend the waxing crescent moon will set
during the early evening hours and will not interfere with meteor observing.
The estimated total hourly rates for evening observers this week is near
four
from the northern hemisphere and two for observers south of the equator. For
morning observers the estimated total hourly rates should be near twenty one
from the northern hemisphere and ten as seen from the southern hemisphere.
The actual rates will also depend on factors such as personal light and
motion perception, local weather conditions, alertness and experience in
watching meteor activity.

The radiant (the area of the sky where meteors appear to shoot from)
positions and rates listed below are exact for Saturday night/Sunday morning
October 9/10. These positions do not change greatly day to day so the listed
coordinates may be used during this entire period. Most star atlases
(available at science stores and planetariums) 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 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 latitude. It must be remembered that meteor activity is
rarely seen at the radiant position. Rather they shoot outwards from the
radiant so it is best to center your field of view so that the radiant lies
at the edge and not the center. Viewing there will allow you to easily trace
the path of each meteor back to the radiant (if it is a shower member) or in
another direction if it is a sporadic. Meteor activity is not seen from
radiants that are located below the horizon. The positions below are listed
in a west to east manner in order of right ascension (celestial longitude).
The positions listed first are located further west therefore are accessible
earlier in the night while those listed further down the list rise later in
the night.

The following showers are expected to be active this week:

The Draconids (GIA) (also known as the Giacobinids) reach maximum activity
on October 8. The exact time of maximum activity can vary so observers are
encouraged to view on the evenings of October 7-9 to try and catch any of
this activity.The radiant is located at 17:28 (262) +54, which places it in
southern Draco, two degrees northwest of the third magnitude star Rastaban
(Beta Draconis). This star is one of the four that form the prominent head
of Draco, also known as the "Lozenge". Expected rates are always a guess.
The new moon will not cause any interference. The best time to view this
activity is as soon as it becomes dark during the early evening hours. Those
located in high northern latitudes can also try viewing this shower during
the morning hours. Due to the extreme northern declination, this shower is
only visible from the southern tropics northward. At 19km/sec., the average
Draconid is extremely slow.

Studies of the IMO video database by Sirko Molau and Juergen Rendtel has
revealed a radiant located in Pisces this time of year. The October Epsilon
Piscids (EPC) are active on only five nights centered on October 9. The
radiant lies at 00:05 (001) +14 which actually lies in eastern Pegasus only
two degrees southwest of the third magnitude star Algenib (Gamma Pegasi).
The radiant is best placed near midnight LDT, when the radiant lies highest
in the sky. Striking the atmosphere at 19 km/sec., the average October
Epsilon Piscid meteor travels very slowly through the skies. Even at
maximum, rates should be less than one per hour no matter your location.

The center of the large Southern Taurid (STA) radiant lies at 02:08 (032)
+09. This position lies in northeastern Cetus, close to the fourth magnitude
star Xi 1 Ceti. Since the radiant is so large, any meteor from eastern
Pisces, northern Cetus, southern Aries, or northeastern Eridanus could be a
candidate for this shower. The radiant is best placed near the meridian near
0200 LDT, but activity may be seen all night long. Although maximum activity
occurs on the 10th, this is a flat plateau-like peak so activity should be
similar all week long. Expect to see up to three Southern Taurids per hour,
no matter your location, when the radiant lies highest in the sky. Striking
the atmosphere at 29 km/sec., the average Southern Taurid meteor travels
slowly through the skies. This shower is also responsible for many of the
fireball reports seen in October.

Another shower derived from the IMO database is the the Sigma Arietids
(SSA). This shower is active from October 12-19 with a peak on the 19th. On
the 12th the radiant is located at 02:52 (043) +22. This position lies in
central Aries, roughly lying between the Pleiades cluster in Taurus and the
second magnitude star Hamal (Alpha Arietis). The radiant is best placed near
0300 LDT, when it lies highest above the horizon. Rates should less than one
per hour. With an entry velocity of 46 km/sec., most activity from this
radiant would be of medium velocity. With a low northern declination these
meteors are slightly better seen from the northern hemisphere.

Another shower derived from the IMO database is the the Zeta Taurids (ZTA).
This shower is active from October 12-17 with a peak on the 16th. On the
12th the radiant is located at 05:08 (077) +15. This position lies on the
Orion-Taurus border, approximately five degrees east of the orange first
magnitude star Aldebaran (Alpha Tauri). The radiant is best placed near 0500
LDT, when it lies highest above the horizon. Rates should less than one per
hour. With an entry velocity of 61 km/sec., most activity from this radiant
would be swift. These meteors would be seen equally well from either
hemisphere.

The Orionids (ORI) are now becoming noticeable from a radiant located at
05:48 (87) +16. This position lies in eastern Taurus, eight degrees north of
the orange first magnitude star Betelgeuse (Alpha Orionis). The radiant
rises near 300 LDT and is best placed on the meridian near 0600. With
maximum activity predicted for October 22, current rates for all locations
would be near one to two per hour as seen after midnight. At 67km/sec., the
average Orionid is swift.

Another shower derived from the IMO database is the the October Ursa
Majorids (OCU). This shower is active from October 12-19 with a peak on the
15th. On the 12th the radiant is located at 09:12 (138) +64. This position
lies in western Ursa Major between the faint stars Tau and Sigma 1 Ursae
Majoris. The radiant is best placed during the last dark hour before dawn
when it lies highest above the horizon in a dark sky. Rates should less than
one per hour. With an entry velocity of 53 km/sec., most activity from this
radiant would be medium-swift. With the high northern declination of the
radiant, these meteors are best seen from the northern hemisphere. It would
be difficult to see any of this activity from locations south of the
equator.

As seen from the mid-northern hemisphere (45N) one would expect to see
approximately fifteen sporadic meteors per hour during the last hour before
dawn as seen from rural observing sites. Evening rates would be near three
per hour. As seen from the mid-southern hemisphere (45S), morning rates
would be near four per hour as seen from rural observing sites and one per
hour during the evening hours. Locations between these two extremes would
see activity between the listed figures.

The list below presents a condensed version of the expected activity this
week. Rates and positions are exact for Saturday night/Sunday morning.

Draconids (GIA) - 17:28 (262) +54   Velocity - 19km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

October Epsilon Piscids (EPC) - 00:05 (001) +14   Velocity - 19km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Southern Taurids (STA) - 02:08 (032) +09   Velocity - 29km/sec.
Northern Hemisphere - 3 per hr. Southern Hemisphere - 3 per hr.

Sigma Arietids (SSA) - 02:52 (043) +22   Velocity - 46km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr.

Zeta Taurids (ZTA) - 05:08 (077) +15   Velocity - 61km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr

Orionids (ORI)  - 05:48 (87) +16   Velocity - 67km/sec.
Northern Hemisphere - 2 per hr. Southern Hemisphere - 2 per hr

October Ursa Majorids (OCU)  - 09:12 (138) +64   Velocity - 53km/sec.
Northern Hemisphere - <1 per hr. Southern Hemisphere - <1 per hr

*For a detailed explanation on the different classes of meteor showers and
other astronomical terms, please visit:
http://www.amsmeteors.org/showers.html#X2010

Clear Skies!
Robert Lunsford
American Meteor Society