(meteorobs) Meteor Activity Outlook for October 4-10, 2014

[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 many 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 the big story of the month reaching maximum activity on the 22nd. This display can be seen equally well from both hemispheres which definitely helps out observers located in the sporadic-poor southern hemisphere this time of year.

During this period the moon reaches its full phase on Wednesday October 8th. At this time the moon is located opposite the sun and will be above the horizon all night long. This weekend the waxing gibbous moon will set during the early morning hours allowing a couple of hours to view meteor activity under dark skies. The estimated total hourly meteor rates for evening observers this week is near 3 as seen from the northern hemisphere and 2 as seen from southern tropical latitudes. For morning observers the estimated total hourly rates should be near 17 for observers located in mid-northern latitudes and 12 for south tropical observers. Note that meteor rates are reduced this week during the evening hours due to moonlight. 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. Note that the hourly rates listed below are estimates as viewed from dark sky sites away from urban light sources. Observers viewing from urban areas will see less activity as only the brightest meteors will be visible from such locations.

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 4/5. 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.

These sources of meteoric activity are expected to be active this week:

The Draconids (GIA) are expected to be active on five evenings from October 6-10. The normal maximum is expected to occur anywhere from 15:00 UT October 8 to 0800 UT October 9. There is also a slight possibility of enhanced rates on October 6th from 19-22 Universal Time from a radiant 8 degrees south of the normal one. The normal radiant lies at 17:28 (262) +56. This position lies in southeastern Draco, very close to the position occupied by the faint star known as Kuma (Nu Draconis). This activity is best seen just as soon as it becomes totally dark. The expected hourly rates are a guess ranging from 0-5, most likely 0-1. With an entry velocity of 19 km/sec., the average Draconid meteor would be of very slow velocity. These meteors are poorly seen from the southern hemisphere due to the low radiant altitude seen from below the equator.

The Southern Taurids (STA) are currently active from a radiant located at 01:52 (028) +08. This position lies in southeastern Pisces, close to the faint star known as Omicron Piscium. These meteors may be seen all night long but the radiant is best placed near 0200 LDT when it lies on the meridian and is located highest in the sky. Rates at this time should be near 3 per hour regardless of your location. With an entry velocity of 29 km/sec., the average Southern Taurid meteor would be of slow velocity.

The Orionids (ORI) are active from a radiant at 05:40 (085) +14, which places it in northern Orion, 4 degrees northeast of the 3rd magnitude star known as Meissa (Lambda Orionis). This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Rates this week would be near 2 per hour no matter your location. With an entry velocity of 67 km/sec., most activity from this radiant would be of swift speed.

Recent analysis of the IMO video database has shown that the Epsilon Geminids (EGE) are active as early as September 29. The current radiant position would be located near 05:52 (088) +30, which places it in southern Auriga, 4 degrees west of the 4th magnitude star known as Kappa Aurigae. This area of the sky is best placed in the sky during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates should be near 1 per hour as seen from the northern hemisphere and less than 1 when view south of the equator. With an entry velocity of 70 km/sec., most activity from this radiant would be of swift speed.

The Psi Aurigids (PSA) were discovered among the radiants found by the IMO network of video cameras. This weak shower is active from October 8-18, which maximum activity occurring on the 15th. On the 8th, the radiant is located at 06:52 (103) +41. This position lies in a remote area of eastern Auriga, halfway between Castor (Alpha Geminorum) and Menkalinan (Beta Aurigae). This area of the sky is best placed in the sky during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates should be less than 1 per hour no matter your location. With an entry velocity of 68 km/sec., most activity from this radiant would be of swift speed.

The Daytime Sextantids (DSX) are mainly thought of as a daylight shower, only visible by radio and radar means. Actually the radiant lies slightly more than 30 degrees west of the sun and members of this shower should be visible during the last hour before the start of nautical twilight, when the sun lies 12 degrees below the horizon. Shower members would shoot upwards from the eastern horizon as dawn is breaking. The International Meteor Organization is asking observers to try and view activity from this source between September 25 and October 6. Maximum activity is thought to occur on September 29th. The radiant should be considered to lie at 10:16 (154) -01. This position lies in central Sextans, 3 degrees east of the 4th magnitude star known as Alpha Sextantis. This area also lies a dozen degrees south of the bright star Regulus (Alpha Leonis). This is one of the stronger "daytime" showers so the visual observer may see several meteors from this source each morning during the period mentioned above. With an entry velocity of 33 km/sec., most activity from this radiant would be of medium-slow velocity. These meteors can be seen equally well from both hemispheres.

The October Camelopardalids (OCT) were first noticed by Peter Jenniskens and mentioned in his book Meteor Showers and their Parent Comets. IMO video data has confirmed this activity which is short-lived and best seen on the mornings of October 5 and 6. The radiant lies at 11:12 (168) +79, which places it in a very remote portion of eastern Camelopardalis.  The easiest way to pinpoint this radiant is to draw a line through the bottom  of the "Little Dipper" (Gamma and Beta Ursae Minoris) westward. Draw another line from the "pointers" in teh "Big Dipper" (Alpha and Beta Ursae Majoris) and extend it northward Polaris. Where these 2 lines intersect will be close to the OCT radiant. This area of the sky is above the horizon most of the night for most observers in the northern hemisphere but is best placed in the sky during the last hour before dawn, when it lies highest above the horizon. Rates at maximum would be near 1 per hour as seen from the northern hemisphere. These meteors are basically invisible from locations south of the equator. With an entry velocity of 44 km/sec., most activity from this radiant would be of medium velocity.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 10 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 2 per hour. As seen from the tropical southern latitudes (25S) morning rates would be near 6 per hour as seen from rural observing sites and 1 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Note that sporadic rates are reduced this week during the evening hours due to moonlight.

These sources of meteoric activity are expected to be active this week. Rates 
and positions are exact for Saturday night/Sunday morning except where noted in 
the shower descriptions. 

Draconids (GIA) -  17:28 (262) +56  Velocity - 19km/sec. 
Northern Hemisphere - 1> per hr.   Southern Hemisphere - 1> per hr
 
Southern Taurids (STA) - 01:52 (028) +08  Velocity - 29km/sec. 
Northern Hemisphere - 3 per hr.   Southern Hemisphere - 3 per hr 
 
Orionids (ORI) - 05:40 (085) +14  Velocity - 67km/sec. 
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 2 per hr. 
 
Epsilon Geminids (EGE) - 05:52 (088) +30  Velocity - 70km/sec. 
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr. 
 
Psi Aurigids (PSA) - 06:52 (103) +41  Velocity - 68km/sec. 
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr. 
 
Daytime Sextantids (DSX) - 10:16 (154) -01  Velocity - 33km/sec. 
Northern Hemisphere - 1 per hr.   Southern Hemisphere - 1 per hr. 

Oct. Camelopardalis (OCT) - 11:12 (168) +79  Velocity - 44km/sec. 
Northern Hemisphere - 1 per hr.   Southern Hemisphere - <1 per hr. 
  
Clear Skies! 
Robert Lunsford 	 
American Meteor Society