Meteor Activity Outlook for July 15-21, 2017

- 0 Comment - In:

Perseid meteors over East Point Lighthouse , NJ – August 2012 © Jeff Berkes

During this period the moon will reach its last quarter phase on Sunday July 16. While the half-illuminated moon will certainly cast some glare in the night sky, it is still much less bright than the full moon. Therefore successful meteor observations can be obtained by simply keeping the moon out of your field of view while observing. Since the moon rises near midnight for observers located in mid-northern latitudes, the evening hours will be free of interfering moonlight. Unfortunately this is also the slowest time of night for meteor activity. Rates will be reduced during the morning hours due to moonlight but activity will still be stronger in the morning despite the moonlight. The estimated total hourly meteor rates for evening observers this week is near 3 for those viewing from the northern hemisphere and 3 for those located south of the equator. For morning observers the estimated total hourly rates should be near 12 as seen from mid-northern latitudes (45N) and 12 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. Evening rates are reduced due to 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 July 15/16. 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 far 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.

Radiant Positions at 10pm LDT

Radiant Positions at 10:00pm Local Daylight Saving Time

Radiant Positions at 01:00 Local Daylight Saving Time

Radiant Positions at 01:00 Local Daylight Saving Time

Radiant Positions at 4am LDT

Radiant Positions at 4:00 Local Daylight Saving Time

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

.

The alpha Capricornids (CAP) are active from July 3 through August 11 with maximum activity occurring during the last week of July. The broad maximum occurs anywhere from July 25 to the 30th with visual rates usually around 3 per hour. The radiant is currently located at 19:28 (292) -13, which places it in northwestern Sagittarius, about 10 degrees west of the naked eye double star known as Algedi (alpha 2 Capricorni). This radiant is best placed near 0100 local summer time (LST), when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be less than 1 as seen from mid-northern latitudes and 1 as seen from tropical southern latitudes. With an entry velocity of 22 km/sec., the average alpha Cap meteor would be of slow velocity.

The center of the large Anthelion (ANT) radiant is currently located at 20:24 (306) -19. This position lies in western Capricornus, 5 degrees south of the 3rd magnitude star known as Dabih (beta Capricorni). Due to the large size of this radiant, Anthelion activity may also appear from the nearby constellation of Microscopium, western Aquarius, and eastern Sagittarius as well as Capricornus. This radiant is best placed near 0200 LST, when it lies on the meridian and is located highest in the sky. Hourly rates at this time should be near 1 as seen from mid-northern latitudes and 2 as seen from tropical southern latitudes. With an entry velocity of 30 km/sec., the average Anthelion meteor would be of medium-slow velocity.

The Northern June Aquilids (NZC) were discovered by Zdenek Sekanina. These meteors are active from June 5-July 22, with maximum activity occurring on the July 3. The current position of the radiant is 21:28 (322) -02. This position lies in northern Aquarius, 4 degrees north of the 3rd magnitude star known as Sadalsuud (beta Aquarii). Current rates are expected to less than 1 per hour, no matter your location. With an entry velocity of 38 km/sec., the average Northern June Aquilid meteor would be of medium speed.

The epsilon Pegasids (EPG) were discovered by Dr. Peter Brown and associates using radar techniques at the University of Western Ontario. This stream is encountered from July 3-23, with maximum activity occurring on July 11. The radiant is currently located at 22:20 (335) +15. This area of the sky is located in western Pegasus, 10 degrees northeast of the 2nd magnitude star known as Enif (epsilon 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. Rates are expected to be less than 1 per hour this week no matter your location. Shower members would most likely be faint and difficult to observe unless viewed from a rural location. With an entry velocity of 28 km/sec., the average meteor from this source would be of medium-slow velocity.

The July Pegasids (JPE) have been noticed for some time now but have had a checkered history. It has been added, dropped, and then re-added to several radiant lists. Video studies within the past 10 years has positively identified this source as an active radiant during the entire month of July. Maximum activity occurs on July 10th. The radiant is currently located at 23:32 (353) +12. This area of the sky is located in southern Pegasus, 6 degrees southeast of the 2nd magnitude star known as Markab (alpha 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. Rates are expected to be near 1 per hour this week no matter your location. With an entry velocity of 68 km/sec., the average meteor from this source would be of swift velocity.

The first members of the Perseid (PER) meteor shower should become visible this week from a radiant located at 00:36 (009) +51. This position is not is Perseus, rather it lies in southern Cassiopeia, 5 degrees south of the 2nd magnitude star known as Schedar (alpha Cassiopeiae). This area of the sky is best placed for viewing during the last dark hour before dawn when it lies highest in the sky. Maximum is not until August 12 so current rates are expected to be near 1 per hour as seen from the northern hemisphere and less than 1 as seen from south of the equator. Unfortunately these meteors are not well seen from the southern hemisphere. With an entry velocity of 59 km/sec., the average meteor from this source would be of swift velocity.

The 49 Andromedids (FAN) were discovered by Željko Andreić et al of the Croatian Meteor Network, using databases from SonotaCo, 2013 and CMN, 2013). These meteors are active from July 6 through August 14 with maximum activity occurring on July 21. The current position of the radiant is 01:20 (020) +46. This position lies in northeastern Pegasus, just south of the 4th magnitude star known as phi Andromedae. Rates are currently expected to be less than 1 per hour no matter your location. With an entry velocity of 60 km/sec., the average 49 Andromedid meteor would be of swift speed.

The psi Cassiopeiids (PCA) were also discovered by Zdenek Sekanina in his study study of radio streams. These meteors are active from July 5 through August 7 with maximum activity occurring on July 22. The current position of the radiant is 01:40 (025) +71. This position lies in northern Cassiopeia, near the faint star known as 50 Cassiopeiae. Rates are currently expected to be less than 1 per hour no matter your location. With an entry velocity of 60 km/sec., the average psi Cassiopeiid meteor would be of swift speed.

The phi Piscids (PPS) were also discovered by Dr. Peter Brown and associates. This shower was later verified by Dr. Peter Jenniskens and David Holman using data from the CAMS network in northern California. These meteors are active from June 8 through August 2 with maximum activity occurring on July 5. The current position of the radiant is 01:52 (028) +29. This position lies in western Triangulum, just south of the 3rd magnitude star known as Mothallah (alpha Trianguli). Rates are currently expected to 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 66 km/sec., the average Pi Piscid meteor would be of swift speed.

The c-Andromedids (CAN) were 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 27 with maximum activity occurring on July 9. The radiant currently lies at 02:28 (037) +50, which places it in extreme northeastern Andromeda, close to the very faint stars star 64 and 65 Andromedae. The bright 2nd magnitude star Mirfak (alpha Persei) lies 15 degrees to the east. 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 near 2 per hour form those in the northern hemisphere and 1 per hour for those south of the equator. With an entry velocity of 58 km/sec., the average meteor from this source would be of swift velocity.

The July chi Arietids (JXA) were discovered by two investigating teams in Europe using video data from European viDeo MeteOr Network Database (EDMOND), SonotaCo, 2013; and CMN, 2013. Activity from this stream is seen from July 2 though August 1 with maximum activity occurring on July 13. The radiant currently lies at 02:32 (038) +10, which places it on the Aries/Cetus border, 2 degrees north of the 4th magnitude star known as chi 2 Ceti. This area of the sky is best seen during the last dark hour before dawn when the radiant lies highest in a dark sky. Current rates are expected to be less than 1 per hour during this period. With an entry velocity of 69 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 7 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 betwe9n the listed figures. Morning rates are reduced 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.

SHOWER DATE OF MAXIMUM ACTIVITY CELESTIAL POSITION ENTRY VELOCITY CULMINATION HOURLY RATE CLASS
RA (RA in Deg.) DEC Km/Sec Local Daylight Saving Time North-South
alpha Capricornids (CAP) Jul 27 19:28 (292) -13 22 01:00 <1 – 1 III
Anthelions (ANT) 20:24 (306) -19 30 02:00 1 – 2 III
Northern June Aquilids (NZC) Jul 03 21:28 (322) -02 38 03:00 <1 – <1 II
epsilon Pegasids (EPG) Jul 11 22:20 (335) +15 28 04:00 <1 – <1 IV
July Pegasids (JPE) Jul 10 23:32 (353) +12 68 05:00 1 – 1 IV
Perseids (PER) Aug 12 00:36 (009) +51 59 06:00 1 – <1 IV
49 Andromedids (FAN) Jul 21 01:20 (020) +46 60 07:00 <1 – <1 IV
psi Cassiopeiids (PCA) Jul 22 01:40 (025) +71 58 07:00 <1 – <1 IV
phi Piscids (PPS) Jul 05 01:52 (028) +29 66 07:00 1 – <1 IV
c-Andromedids (CAN) Jul 09 02:28 (037) +50 58 08:00 1 – <1 IV
July chi Arietids (JXA) Jul 13 02:32 (038) +10 69 08:00 <1 – <1 IV

Tags:

Leave a Reply

Your email address will not be published. Required fields are marked *