(meteorobs) Meteor Activity Outlook for October 18-24, 2014

[Robert Lunsford]

During this period the moon reaches its new phase on Thursday October 23th. At this time the moon is located near the sun and cannot be seen at night. This weekend the waning crescent moon will rise during the early morning hours but will offer little trouble as long as the observer keeps the moon out of their field of view. 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 12 for observers located in mid-northern latitudes and 7 for south tropical observers. Rates are slightly reduced for the morning hours during this period 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 18/19. 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 Gamma Piscids (GPS) are a weak shower active from October 14 through the 21st with maximum activity occurring on the 17th. At maximum the radiant is located at 01:10 (017) +17. This position lies in central Pisces, 5 degrees northwest of the faint star known as Eta Piscium. Rates of less than 1 per hour are expected, even at maximum. With an entry velocity of 21 km/sec., the average Gamma Piscid meteor would be of slow velocity.

The Southern Taurids (STA) are currently active from a radiant located at 02:36 (039) +12. This position lies in southern Aries, 3 degrees northwest of the 4th magnitude star known as Mu Ceti. These meteors may be seen all night long but the radiant is best placed near 0100 local daylight time (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) reach maximum activity on Tuesday night/Wednesday morning October 21/22. Unlike most major showers the Orionids offer a broad maximum with similar rates on the nights prior and after maximum. This weekend the radiant lies at 06:16 (094) +16, which places it in northeastern Orion, 4 degrees west of the 2nd magnitude star known as Alhena (Gamma Geminorum). This area of the sky is best placed near 0500 LDT, when it lies highest above the horizon. Rates this weekend would be near 10 per hour no matter your location. Rates should increase to 15-20 per hour at maximum With an entry velocity of 67 km/sec., most activity from this radiant would be of swift speed.

The Epsilon Geminids (EGE) also reach maximum activity on the morning of October 22nd. On this morning the radiant is located at 06:58 (105) +28. This position is located in northern Gemini, 3 degrees northeast of the star known as Mebsuta (Epsilon Geminorum). 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. This is fairly close to the Orionid radiant so care should be taken to separate these two sources. The best way to do this is to include both radiants within your field of view so that meteors can be easily traced back to their source. Current rates should be near 2 per hour as seen from the northern hemisphere and 1 when view south of the equator. This should increase to near 3 per hour at maximum. With an entry velocity of 70 km/sec., most activity from this radiant would be of swift speed.

The October Lyncids (OLY) were discovered by Peter Jenniskens and verified by IMO video data. This weak shower is active from October 16-24 with no distinct night of maximum activity. The date listed in the shower table is the midpoint of the activity curve. The radiant is currently located near 07:20 (110) +53. This position lies in a remote area of central Lynx, halfway between the stars Omicron Ursae Majoris 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 Tau Cancrids (TCA) are active from October 9-25 and also has no distinct night of maximum activity. The date listed in the shower table is the midpoint of the activity curve. This shower was also discovered by Peter Jenniskens and verified by IMO video data. The radiant currently located at 09:04 (136) +30. This position lies in northern Cancer, close to the faint star known as Tau Cancri. 4th magnitude Iota Cancri lies 3 degrees to the southwest. 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 2 per hour as seen from the northern hemisphere and  1 as seen from south of the equator. With an entry velocity of 69 km/sec., most activity from this radiant would be of swift speed.

The Leonis Minorids (LMI) are active from October 17-27 with maximum activity occurring on October 22nd. This radiant is currently located at 10:28 (157) +37, which places it in northeast Leo Minor, very close to the position occupied by the fourth magnitude star Beta Leonis Minoris . The radiant is best placed just before dawn when it lies highest in a dark sky. This shower is better situated for observers situated in the northern hemisphere where the radiant rises far higher into the sky before the start of morning twilight. Rates at maximum should be near 4 per hour for those in the northern hemisphere and 2 per hour as seen south of the equator. At 60km/sec., the average Leonis Minorid is swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately 8 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 3 per hour. As seen from the tropical southern latitudes (25S) morning rates would be near 5 per hour as seen from rural observing sites and 2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Note that sporadic rates are slightly reduced this week during the morning hours due to moonlight.

The list below offers the information from above in tabular form. Rates and positions are exact for Saturday night/Sunday morning except where noted in the shower descriptions.
 
Gamma Piscids (GPS) -  01:10 (017) +17  Velocity - 21km/sec. 
Northern Hemisphere - 1> per hr.   Southern Hemisphere - 1> per hr 
 
Southern Taurids (STA) - 02:36 (039) +12  Velocity - 29km/sec. 
Northern Hemisphere - 3 per hr.   Southern Hemisphere - 3 per hr 
 
Orionids (ORI) - 06:16 (094) +16  Velocity - 67km/sec. 
Northern Hemisphere - 10 per hr.   Southern Hemisphere - 10 per hr. 
 
Epsilon Geminids (EGE) - 06:58 (105) +28  Velocity - 70km/sec. 
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 1 per hr. 
 
Oct. Lyncids (OLY) - 07:20 (110) +53  Velocity - 68km/sec. 
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr. 
 
Tau Cancrids (TCA) - 09:04 (136) +30  Velocity - 69km/sec. 
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 1 per hr. 
 
Leonis Minorids (LMI) - 10:28 (157) +37  Velocity - 60km/sec. 
Northern Hemisphere - 4 per hr.   Southern Hemisphere - 2 per hr. 
  
Clear Skies! 
Robert Lunsford 	 
American Meteor Society