During this period the moon reaches its last quarter phase on Tuesday June 25th. At this time the moon is located 90 degrees west of the sun and rises between 0100 and 0200 local summer time (LST). As the week progresses, the waning crescent moon will rise later in the morning with each passing night, allowing more of the night to be free of interfering moonlight. The estimated total hourly meteor rates for evening observers this week is near 3 for those viewing from the northern hemisphere and 4 for those located south of the equator. For morning observers the estimated total hourly rates should be near 6 as seen from mid-northern latitudes (45N) and 10 as seen from tropical southern locations (25S). 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. Morning rates are reduced by moonlight during this period. 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 June 22/23. 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 June Bootids (JBO) are usually a very weak shower that occasionally produces outbursts. Nothing out of the ordinary is expected this year. These meteors are best seen from June 23-25 with maximum activity occurring on the 24th. At maximum the radiant is located at 14:58 (224) +48. This position lies in northwestern Bootes, 15 degrees east of the second magnitude star known as Alkaid (Eta Ursae Majoris). This radiant is best placed in the evening sky just as the sky 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 18 km/sec., the average June Bootid meteor would be of very slow velocity.
The center of the large Anthelion (ANT) radiant is currently located at 18:56 (284) -23. This position lies in central Sagittarius, 4 degrees north of the 2nd magnitude star known as Nunki (sigma Sagittarii). Due to the large size of this radiant, anthelion activity may also appear from southeastern Ophiuchus and Scutum as well as Sagittarius. This radiant is best placed near 0200 LST, when it lies on the meridian and is located highest in the sky. Rates at this time should be near 2 per hour as seen from mid-northern latitudes (45 N) and 3 per hour as seen from the southern tropics (S 25). With an entry velocity of 30 km/sec., the average anthelion meteor would be of slow velocity.
The Northern June Aquilids (NZC) are active from a radiant located at 20:00 (300) -08. This area of the sky is located in southern Aquila, 7 degrees northwest of the 3rd magnitude star known as Algiedi Prima (alpha1 Capricorni). This radiant is best placed near 0300 LST, when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 1 no matter your location. With an entry velocity of 38 km/sec., the average meteor from this source would be of medium-slow velocity. An interesting fact about this source is that it may be related to the Northern delta Aquariids of August. Where and when this source ends coincides with the start and position of the Northern delta Aquariids.
The Southern June Aquilids (SZC) were discovered by G. Gartrell and W. G. Elford, in their study of Southern Hemisphere meteor streams. This stream is active from June 9 through July 17 with maximum activity occurring on July 6. The radiant is currently located at 20:22 (306) -32. This area of the sky is actually located in southeastern Sagittarius, 5 degrees northeast of the 4th magnitude star known as Theta1 Sagittarii. This radiant is best placed near 0300 LDST, when it lies on the meridian and is located highest in the sky. Hourly rates at this time will be less than 1 no matter your location. With an entry velocity of 39 km/sec., the average meteor from this source would be of medium-slow velocity.
The beta Equulids (BEQ) were discovered by Dr. Peter Brown and associates using data from the Canadian Meteor Orbit Radar (CMOR) installation. These meteors are active from June 7-30 with maximum activity occurring on June 15th. The radiant position currently lies at 20:37 (309) +02. This area of the sky lies in eastern Aquila, 3 degrees north of the dim star known as 71 Aquilae. TThis radiant is best placed near 0400 LST, when it lies on the meridian and is located highest in the sky. Hourly rates are expected to be less than 1, no matter your location. With an entry velocity of 33 km/sec., a majority of these meteors will appear to move with medium-slow velocities.
The phi Piscids (PPS) are another discovery by Dr. Peter Brown and associates using data from the Canadian Meteor Orbit Radar (CMOR) installation. These meteors are active from June 8-August 02 with maximum activity occurring on July 5th. The radiant position currently lies at 00:26 (007) +20. This area of the sky lies in north-central Pisces, 5 degrees northeast of the 3rd magnitude star known as Algenib (gamma Pegasi). These meteors are best seen near during the last dark hour of the night when the radiant lies highest in a dark sky. Current rates should be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from south of the equator. With an entry velocity of 67 kilometers per second, a majority of these meteors will appear to move with swift velocities.
The first of the c-Andromedids (CAN) should be seen this week. This stream was discovered by Sirko Molau and Juergen Rendtel using video data from the IMO network. Activity from this source is seen from June 26 through July 27 with maximum activity occurring on July 9. The radiant currently lies at 00:42 (011) +42, which places it in northern Andromeda, almost in contact with the naked eye Andromeda Galaxy. 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 compared to southern latitudes. Current rates would be less than 1 per hour no matter your location. With an entry velocity of 58 km/sec., the average meteor from this source would be of swift velocity.
The last of the Daytime Arietids (ARI) are expected this weekend. These meteors are difficult to catch as the radiant only lies 30 degrees west of the sun. Therefore the only time these meteors are visible is during the last dark hour before dawn. The radiant is currently located at 03:51 (058) +27. This area of the sky is located in western Taurus, 3 degrees north of the naked eye star cluster known as the Pleiades. Current rates are expected to be less than 1 no matter your location. With an entry velocity of 41 km/sec., the average meteor from this source would be of medium velocity.
As seen from mid-northern hemisphere (45N), morning rates would be near 6 per hour as seen from rural observing sites and 1 per hour during the evening hours. As seen from the tropical southern latitudes (25S), one would expect to see approximately 11 sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near 3 per hour. Locations between these two extremes would see activity between the listed figures. Morning rates are reduced during this period due to bright 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.
|SHOWER||DATE OF MAXIMUM ACTIVITY||CELESTIAL POSITION||ENTRY VELOCITY||CULMINATION||HOURLY RATE||CLASS|
|RA (RA in Deg.) DEC||Km/Sec||Local Summer Time||North-South|
|June Bootids (JBO)||Jun 24||14:58 (224) +48||18||23:00||<1 – <1||III|
|Anthelion (ANT)||–||18:56 (284) -23||30||02:00||2 – 3||II|
|Northern June Aquilids (NZC)||Jul 03||20:00 (300) -08||41||03:00||1 – 1||IV|
|Southern June Aquilids (SZC)||Jul 06||20:22 (306) -32||39||03:00||<1 – <1||IV|
|beta Equulids (BEQ||Jun 15||20:37 (309) +02||33||04:00||<1 – <1||IV|
|phi Piscids (PPS)||Jul 05||00:26 (007) +20||67||08:00||1 – <1||IV|
|c-Andromedids (CAN)||Jul 09||00:42 (011) +42||58||08:00||<1 – <1||IV|
|Daytime Arietids (ARI)||Jun 08||03:51 (058) +27||41||11:00||<1 – <1||II|