(meteorobs) Meteor Activity Outlook for July 5-11, 2014

[Robert Lunsford]

During this period the moon reaches its first quarter phase on Saturday July 5th. At this time the half-illuminated moon will set near midnight LDT (Local Daylight Time) as seen from mid-northern latitudes . The morning hours will be free of interfering moonlight allowing meteor observers the best possible view of early July activity. With each passing night the moon sets approximately 45 minutes later so by the end of the week the moon will be in the sky nearly all night long. So the key for this period is to view early before the moon becomes too much of a problem. The estimated total hourly meteor rates for evening observers this week is near 4 for observers situated at mid-northern latitudes and 5 for observers viewing from the southern tropics (latitude 25 S.). For morning observers the estimated total hourly rates should be near 15 as seen from the northern hemisphere and 14 as seen from southern tropical latitudes. 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. Evening rates are reduced during this period due to moonlight. 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 July 5/6. 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:

IMO shower #95 is a weak source of activity, discovered among the video data of the IMO, seen from June 27 though July 7. Maximum activity occurred on June 29 when the radiant lies at 16:50 (253) +56. This position lies in southern Draco, ten degrees northwest of the third magnitude star known as Rastaban (Beta Draconis). The radiant has not moved much since maximum so this position is still good for use this week. Activity from this source would be best seen as soon as it becomes dark. Observers in the northern hemisphere have a distinct advantage over those located south of the equator as the radiant lies much higher in the evening sky. No matter your location, little activity is expected from this source. With an entry velocity of 23 km/sec., the average meteor from this source would be of low velocity.

The Alpha Capricornids (CAP) are active for over a month lasting from July 6 through August 10. Unlike most showers, the Alpha Caps have a plateau-like maximum with maximum activity lasting from July 25-30. Since maximum activity is still 3 weeks away, hourly rates will be less than 1 no matter your location. The radiant is currently located at 19:34 (294) -16. This area of the sky is located in northeastern Sagittarius, 3 degrees northeast of the 4th magnitude star known as Rho Sagittarii. The radiant is best placed near 0300 LDT when it lies on the meridian and is highest in the sky. With an entry velocity of 22 km/sec., the average Alpha Capricornid meteor would be of slow velocity.

The center of the large Anthelion (ANT) radiant is currently located at 19:48 (297) -20. This position lies in a remote area of eastern Sagittarius. The nearest bright star is 3rd magnitude Dabih (Beta Capricorni), which lies 8 degrees to the northeast. 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 positioned highest in the sky. Due to the large radiant area, meteors from this source may also appear to radiant from the constellation of Microscopium, Scutum, southern Aquila, western Aquarius, and western Capricornus as well as Sagittarius. Rates at this time should be near 1 per hour as seen from the northern hemisphere and 2 per hour as seen from south of the equator. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of slow velocity.

The Sigma Capricornids (SCA) were discovered by Zdenek Sekanina and are active for a month lasting from June 19 through July 24. Maximum occurred on June 27th. The radiant is located at 20:52 (313) -05. This area of the sky is located in north-central Capricornus, 3 degrees northwest of the 4th magnitude star known as Dorsum (Theta Capricornii). The radiant is best placed near 0300 LDT when it lies on the meridian and is highest in the sky. Rates at this time should be near 2 per hour no matter your location. With an entry velocity of 42 km/sec., the average Sigma Capricornid meteor would be of medium velocity.

Members of the July Pegasids (JPE) should begin appearing this weekend from a radiant located at 22:56 (344) +10. This area of the sky is located in southwestern Pegasus, 3 degrees east of the 3rd magnitude star known as Homam (Zeta Pegasi). This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Maximum activity occurs on July 10th so rates this weekend are expected to be near 1 per hour no matter your location. Rates should increase to near 2 per hour at maximum. With an entry velocity of 68 km/sec., the average meteor from this source would be of swift velocity.

The Pi Piscids (PPI) is a new source of activity discovered by Dr. Peter Brown and his Canadian Meteor Orbit Radar (CMOR) team. Activity is found from this source throughout June and July with maximum activity occurring on July 1st. It is one of the strongest sources of meteors during late June and early July. The radiant is currently located at 01:12 (018) +27. This area of the sky is located in northeastern Pisces, 5 degrees northeast of the 4th magnitude star Eta Andromeda. The radiant is best placed near 0300 LDT when it lies on the meridian and is highest in the sky. Rates at this time should be near two per hour as seen from the northern hemisphere and one per hour as seen from south of the equator. With an entry velocity of 69 km/sec., the average Pi Piscid meteor would be of swift velocity.

The c-Andromedids (CAN) was discovered by Sirko Molau and Juergen Rendtel using video data from the IMO network. Activity from this source is seen from June 26 though July 20 with maximum activity occurring on July 10. The radiant currently lies at 01:38 (025) +47, which places it in northeastern Andromeda, 2 degrees southwest of the 4th magnitude star known as 51 Andromedae. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Observers in the northern hemisphere are better situated to view this activity as the radiant rises much higher in the sky before dawn as seen from northern latitudes. Current rates would be 1-2 shower members as seen from the northern hemisphere before dawn and less than one per hour for observers situated south of the equator. With an entry velocity of 60 km/sec., the average meteor from this source would be of swift velocity.

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 2 per hour. As seen from the tropical southern latitudes (25S), morning rates would be near 8 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. Evening rates are reduced due to lunar glare.

The list below presents a list of radiants that are expected to be active this 
week. Rates and positions are exact for Saturday night/Sunday morning except 
where noted in the shower descriptions. 
 
IMO #95 16:50 (253) +56  Velocity - 23km/sec. 
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr. 
 
Alpha Capricornids (CAP) - 19:34 (294) -16  Velocity - 22km/sec. 
Northern Hemisphere - <1 per hr.   Southern Hemisphere - <1 per hr.  

Anthelions (ANT) - 19:48 (297) -20  Velocity - 29km/sec. 
Northern Hemisphere - 1 per hr.   Southern Hemisphere - 2 per hr 
 
Sigma Capricornids (SCA) - 20:52 (313) -05  Velocity - 42km/sec. 
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 2 per hr. 
 
July Pegasids (JPE) - 22:56 (344) +10  Velocity - 68km/sec. 
Northern Hemisphere - 1 per hr.   Southern Hemisphere - 1 per hr. 
 
Pi Piscids (PPS) - 01:12 (018) +27  Velocity - 69km/sec. 
Northern Hemisphere - 2 per hr.   Southern Hemisphere - 1 per hr. 
 
c-Andromedids (CAN) - 01:38 (025) +47  Velocity - 60km/sec. 
Northern Hemisphere - 1 per hr.   Southern Hemisphere - <1 per hr. 
 
Clear Skies! 
Robert Lunsford 	 
American Meteor Society