Meteor Activity Outlook for August 25-31, 2012

The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.

Meteor activity kicks into high gear in August as seen from the northern hemisphere. The main reason for all this activity is the Perseid shower that peaks on August 12. This shower is active most of the month and remains above the level of the sporadic background for a week centered on August 12. The sporadic activity is also near maximum as seen from the northern hemisphere and is now more than double the rates from just three months ago. As seen from south of the equator, meteor rates are still decent but falling rapidly. The sporadic rates continue their downward slide and the Perseid radiant does not rise high into the sky as seen in the southern hemisphere so rates from this shower are greatly reduced when compared to the northern hemisphere.

During this period the moon reaches its full phase on Friday August 31st. At this time the moon will be 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 few hours of dark skies between moon set and the start of morning twilight in which good activity can be observed. The estimated total hourly meteor rates for evening observers this week is near four for observers located at mid-northern latitudes and three for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near twenty from the mid-northern hemisphere and eight from the mid-southern hemisphere. 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.

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 August 25/26. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following radiants are expected to be active this week:

The Kappa Cygnids (KCG) are winding down but still active from a wide radiant located at 18:28 (268) +63. This position lies in a remote area of southern Draco. The nearest bright star is third magnitude Aldib (Delta Draconis), which lies seven degrees to the northeast. Some readers will notice that this position is west of that given last week. The reason for this seemingly retrograde motion is the different sub-centers of activity that appear within the large radiant area during this month. Observers need not be strict with shower association for this shower due to the wide radiant and these sub-centers of activity. Maximum activity occurred on August 18th so current rates would be less than one per hour no matter your location. With an entry velocity of 23 km/sec. most of these meteors will appear to travel slower than average. The radiant is best placed near 2300 Local Daylight Time (LDT) 11pm Local Daylight Time (LDT) when it lies nearly overhead for much of the Northern Hemisphere. Due to its high northern declination this activity is not well seen from the southern hemisphere.

The large Antihelion (ANT) radiant is currently located at 23:00 (345) -05. This position lies in northeastern Aquarius, four degrees northwest of the fourth magnitude star Phi Aquarii. Due to the large size of this radiant, Antihelion activity may also appear from eastern Capricornus, southern Pisces, southern Pegasus, and western Cetus as well as Aquarius. This radiant is best placed near 0200 LDT, when it lies on the meridian and is located highest in the sky. Rates at this time are expected to be near one per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.

There is an active yet unnamed radiant located just east of the “circlet” of Pisces this week. The exact location for Sunday morning is 23:48 (357) +06. This lies in western Pisces between the fourth magnitude stars Omega and Iota Piscium. Radiant drift per day averages 0.8 degree in right ascension and +0.4 in declination. This radiant is stronger than all but the Perseids so naked eye verification should be fairly easy. This activity is present from August 6th through September 6th with a maximum occurring on August 17th. With an entry velocity of 41 km/sec., most activity from this radiant would be of average velocities.

There is another active yet unnamed radiant located in southern Perseus active only this weekend The exact location for Sunday morning is 03:52 (058) +36. This position lies two degrees west of the fourth magnitude star Xi Persei. This is the fourth most active radiant in the sky so rates would be near one per hour as seen during the morning hours from the mid-northern hemisphere. This radiant is not well placed for viewing south of the equator. With an entry velocity of 69 km/sec., most activity from this radiant would appear as swift meteors.

The Perseids (PER) peaked on Sunday August 12th, producing visible hourly rates near 50 as seen from dark skies. They are still the most active radiant in the sky but rates are now down to only 2-3 shower members per hour as seen from the mid-northern hemisphere during the early morning hours. The current radiant is located at 04:28 (067) +59. This position lies in a blank portion of southern Camelopardlis, five degrees southeast of fourth magnitude star Beta Camelopardalis. With an entry velocity of 61 km/sec., most activity from this radiant would be swift.

The Aurigids (AUR) become active on August 25th but are very weak until the morning of August 30th. Maximum occurs on August 31st when it becomes the most active radiant in the sky. Unfortunately the full moon will spoil the display at this time so only 1-2 shower members will be visible per hour as seen during the morning hours from mid-northern latitudes. Very little activity would be visible from the southern hemisphere. At maximum the radiant is located at 06:02 (091) +39, which places it in eastern Auriga just two degrees north of third magnitude Theta Aurigae. With an entry velocity of 67 km/sec., most activity from this radiant would be swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately fourteen sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near three per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near five per hour as seen from rural observing sites and two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced due to to moonlight during this period.

The list below presents a summary of the expected activity this week. Rates and
positions are exact for Saturday night/Sunday morning August 25/26, but may be
used all week.

Kappa Cygnids (KCG) – 18:28 (268) +63   Velocity 23km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

Antihelions (ANT) – 23:00 (345) -05   Velocity 30km/sec
Northern Hemisphere – 1 per hr   Southern Hemisphere – 1 per hour

Unnamed (UNK) – 23:48 (357) +06   Velocity 41km/sec
Northern Hemisphere – 1 per hr   Southern Hemisphere – 1 per hour

Unnamed (UNK) – 03:52 (058) +36   Velocity 69km/sec
Northern Hemisphere – 1 per hr   Southern Hemisphere – <1 per hour

Perseids (PER) – 04:28 (067) +59   Velocity 61km/sec
Northern Hemisphere – 3 per hr    Southern Hemisphere – 1 per hour

Aurigids (AUR) – 06:02 (091) +39   Velocity 67km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

Clear Skies!
Robert Lunsford
American Meteor Society

Meteor Activity Outlook for August 18-24, 2012

The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.

Meteor activity kicks into high gear in August as seen from the northern hemisphere. The main reason for all this activity is the Perseid shower that peaks on August 12. This shower is active most of the month and remains above the level of the sporadic background for a week centered on August 12. The sporadic activity is also near maximum as seen from the northern hemisphere and is now more than double the rates from just three months ago. As seen from south of the equator, meteor rates are still decent but falling rapidly. The sporadic rates continue their downward slide and the Perseid radiant does not rise high into the sky as seen in the southern hemisphere so rates from this shower are greatly reduced when compared to the northern hemisphere.

During this period the moon reaches its first quarter phase on Friday August 24th. At this time the moon will be located ninety degrees east of the sun and will set near midnight local daylight time (LDT). This weekend the waxing crescent moon will set during the early evening hours and will not interfere with meteor observing during the more productive morning hours. The estimated total hourly meteor rates for evening observers this week is near four for observers located at mid-northern latitudes and three for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near twenty two from the mid-northern hemisphere and twelve from the mid-southern hemisphere. 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.

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 August 18/19. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following radiants are expected to be active this week:

The Kappa Cygnids (KCG) are active from a wide radiant located at 18:28 (277) +59. This position lies in Draco, ten degrees northeast of the second magnitude star Eltanin (Gamma Draconis). Some readers will notice that this position is west of that given last week. The reason for this seemingly retrograde motion is the different sub-centers of activity that appear within the large radiant area during this month. Observers need not be strict with shower association for this shower due to the wide radiant and these sub-centers of activity. Maximum activity occurs on August 18th so current rates would be near two per hour from the northern hemisphere and less than one shower member per hour from south of the equator. With an entry velocity of 23 km/sec. most of these meteors will appear to travel slower than average. The radiant is best placed near 2300 LDT 11pm Local Daylight Time (LDT) when it lies nearly overhead for much of the Northern Hemisphere. Due to its high northern declination this activity is not well seen from the southern hemisphere.

The large Antihelion (ANT) radiant is currently located at 22:36 (339) -07. This position lies in central Aquarius, four degrees northeast of the fourth magnitude star Sadalsuud Sadalsuud (Beta Aquarii). Due to the large size of this radiant, Antihelion activity may also appear from eastern Capricornus, western Pisces, and southern Pegasus, western Cetus as well as Aquarius. This radiant is best placed near 0200 LDT, when it lies on the meridian and is located highest in the sky. Rates at this time are expected to be near two per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.

There is an active yet unnamed radiant located within the “circlet” of Pisces this week. The exact location for Sunday morning is 23:27 (352) +04. Radiant drift per day averages 0.8 degree in right ascension and +0.4 in declination. This radiant is stronger than all but the Perseids and the Antihelons so naked eye verification should be fairly easy. This activity is present from August 6th through September 6th with a maximum occurring on August 17th. With an entry velocity of 41 km/sec., most activity from this radiant would be of average velocities.

The Delta Aquariids (SDA) are near the end of their activity for 2012. They are still weakly active from a radiant located at 23:54 (359) -11. This position is located on the Aquarius/Cetus border, four degrees northeast of the Omega 2 Aquarii. Current hourly rates would be less than one no matter your location. The radiant is best placed near 0300 LDT, when it lies highest in the sky. With an entry velocity of 42 km/sec., most activity from this radiant would be of average velocities.

There is another active yet unnamed radiant located close to Almach (Gamma Andromedae) this week. The exact location for Sunday morning is 02:04 (031) +41. Radiant drift averages 0.7 degree in right ascension and -0.3 in declination per day. This radiant is probably the weakest of all listed this week, yet with careful monitoring, several of these meteors should be visible each night . This activity is present from August 18th through the 25th with the maximum occurring on the 25th. With an entry velocity of 69 km/sec., most activity from this radiant would appear as swift meteors.

The Perseids (PER) peaked on Sunday August 12th, producing visible hourly rates near 50 as seen from dark skies. They are still weakly active from a radiant located at 03:47 (057) +59. This position lies in southwestern Camelopardlis, ten degrees northeast of the second magnitude star Mirfak (Alpha Persei). Current rates would be near five per hour from the  northern hemisphere and two per hour as seen from south of the equator. With an entry velocity of 61 km/sec., most activity from this radiant would be swift.

A new source found by the IMO video cameras to be active this time of year are the Alpha Triangulids (ATR). This radiant has recently been found to be active later than previously published, with the activity period ranging from July 25 through August 21 with maximum activity occurring on July 27. Current rates would be less than one per hour, no matter your location. The radiant is currently located at 03:44 (056) +38, which is actually situated in southern Perseus, four degrees southwest of Epsilon Persei. The radiant is best placed during the last hour before dawn, when it lies highest in a dark sky. With an entry velocity of 67 km/sec., the average Alpha Triangulid meteor would be swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately ten sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near three per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near five per hour as seen from rural observing sites and two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.

The list below presents a summary of the expected activity this week. Rates and
positions are exact for Saturday night/Sunday morning August 11/12, but may be
used all week.

Kappa Cygnids (KCG) – 18:28 (277) +59   Velocity 23km/sec
Northern Hemisphere – 2 per hr   Southern Hemisphere – <1 per hour

Antihelions (ANT) – 22:36 (339) -07   Velocity 30km/sec
Northern Hemisphere – 2 per hr   Southern Hemisphere – 2 per hour

23:27 (352) +04   Velocity 41km/sec
Northern Hemisphere – 2 per hr   Southern Hemisphere – 2 per hour

Delta Aquariids (SDA) – 23:54 (359) -11   Velocity 42km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

02:04 (031) +41   Velocity 67km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

Perseids (PER) – 03:47 (057) +59   Velocity 61km/sec
Northern Hemisphere – 5 per hr   Southern Hemisphere – 2 per hour

Alpha Triangulids (ATR) – 03:16 (049) +37   Velocity 67km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

Clear Skies!
Robert Lunsford
American Meteor Society

 

Perseids Peak Tonight

The Perseid meteor shower is scheduled to peak this morning (morning of August 12). For a thorough guide on how to observe this shower see the American Meteor Society’s ‘Viewing the 2012 Perseid Meteor Shower‘ article.

The chart below shows the latest ZHR measurements based on meteor counts submitted to the International Meteor Organization. [Update: recent results from Europe are showing a ZHR of 40-60 meteors per hour.]

Live graph of ZHR values for the 2012 Perseids. Graph created by the International Meteor Organization (IMO) from member meteor counts. Credit: IMO.

While outside this morning watching the meteors, don’t forget to look to the east. The Moon, Jupiter and Venus are nicely lined up against the backdrop of the winter Milky Way.

View towards the east before dawn on the morning of August 12 (night of the Perseids peak). Image created with Stellarium.

Meteor Activity Outlook for August 11-17, 2012

The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.

Meteor activity kicks into high gear in August as seen from the northern hemisphere. The main reason for all this activity is the Perseid shower that peaks on August 12. This shower is active most of the month and remains above the level of the sporadic background for a week centered on August 12. The sporadic activity is also near maximum as seen from the northern hemisphere and is now more than double the rates from just three months ago. As seen from south of the equator, meteor rates are still decent but falling rapidly. The sporadic rates continue their downward slide and the Perseid radiant does not rise high into the sky as seen in the southern hemisphere so rates from this shower are greatly reduced when compared to the northern hemisphere.

During this period the moon reaches its new phase on Friday August 17th. At this time the moon will be located near the sun and will not be visible at night. This weekend the waning crescent moon will rise during the early morning hours, giving off some glare in the eastern sky. You can compensate for this by facing away from the moon in another direction where the sky should be largely unspoiled by moonlight. The estimated total hourly meteor rates for evening observers this week is near six for observers located at mid-northern latitudes and three for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near sixty from the mid-northern hemisphere and twenty from the mid-southern hemisphere. 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 slightly reduced due to moonlight.

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 August 11/12. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following radiants are expected to be active this week:

The Kappa Cygnids (KCG) are active from a wide radiant located at 19:00 (285) +51. This position lies on the Cygnus/Draco border, eight degrees northwest of the third magnitude star Rukh (Delta Cygni). Maximum activity occurs on August 17th so current rates would be one per hour from the northern hemisphere and less than one shower member per hour from south of the equator. With an entry velocity of 23 km/sec. most of these meteors will appear to travel slower than average. The radiant is best placed near 2300 LDT 11pm Local Daylight Time (LDT) when it lies nearly overhead for much of the Northern Hemisphere. Due to its high northern declination this activity is not well seen from the southern hemisphere.

The large Antihelion (ANT) radiant is currently located at 22:08 (332) -09. This position lies in central Aquarius, two degrees southwest of the fourth magnitude star Theta Aquarii. Due to the large size of this radiant, Antihelion activity may also appear from eastern Capricornus, western Pisces, and southwestern Pegasus as well as Aquarius. This radiant is best placed near 0200 LDT, when it lies on the meridian and is located highest in the sky. Rates at this time are expected to be near two per hour as seen from the northern hemisphere and three per hour as seen from south of the equator. With an entry velocity of 30 km/sec., the averag meteor would be of slow velocity.

The Delta Aquariids (SDA) are still active from a radiant located at 23:28 (352) -13. This position is located in east-central Aquarius, four degrees southeast of the naked eye triple star known as Psi Aquarii. Current hourly rates would be one from the northern hemisphere and two from south of the equator. The radiant is best placed near 0300 LDT, when it lies highest in the sky. With an entry velocity of 42 km/sec., most activity from this radiant would be of average velocities.

The Eta Eridanids (ERI) are active from July 24 through August 18 with maximum activity occurring on August 8. The current radiant position is 03:00 (045) -10, which places it in western Eridanus, just one degree southeast of the fourth magnitude star Eta Eridani. Current rates would be near one per hour no matter your location. The radiant is best placed during the last hour before dawn, when it lies highest in a dark sky. With an entry velocity of 66 km/sec., the average Eta Eridanid meteor would be swift.

The Perseids (PER) peak on Sunday morning from a radiant located at 03:12 (048) +58. This position lies near the intersection of Cassiopeia, Perseus, and Camelopardalis. Gamma Persei lies four degrees to the southwest of the radiant. The radiant is circumpolar north of 32 degrees north latitude but best placed during the last hour before the start of morning twilight, when it lies highest in a dark sky. Expected maximum rates, when the radiant is located highest in a dark sky, are near forty per hour as seen from the northern hemisphere and ten per hour as seen from tropical southern latitudes. Rates are slightly reduced due to moonlight, as the 25 percent illuminated moon lies fairly close to the radiant. Activity from this source is not visible south of 35 degrees south latitude. With an entry velocity of 61 km/sec., most activity from this radiant would be swift. For more information on how to watch for Perseid meteors, see the article at: Viewing the 2012 Perseid Meteor Shower.

A new source found by the IMO video cameras to be active this time of year are the Alpha Triangulids (ATR). This radiant has recently been found to be active later than previously published, with the activity period ranging from July 25 through August 21 with maximum activity occurring on July 27. Current rates would be less than one per hour, no matter your location. The radiant is currently located at 03:16 (049) +37, which is actually situated in southern Perseus, five degrees southeast of the famous variable star known as Algol (Beta Persei). The radiant is best placed during the last hour before dawn, when it lies highest in a dark sky. With an entry velocity of 67 km/sec., the average Alpha Triangulid meteor would be swift.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately twelve sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be near four per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near six per hour as seen from rural observing sites and two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are slightly reduced due to moonlight.

The list below presents a summary of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning August 11/12, but may be used all week.

Kappa Cygnids (KCG) – 19:00 (285) +51   Velocity 23km/sec
Northern Hemisphere – 1 per hr   Southern Hemisphere – <1 per hour

Antihelions (ANT) – 22:08 (332) -09   Velocity 30km/sec
Northern Hemisphere – 2 per hr   Southern Hemisphere – 3 per hour

Delta Aquariids (SDA) – 23:28 (352) -13   Velocity 42km/sec
Northern Hemisphere – 1 per hr   Southern Hemisphere – 2 per hour

Eta Eridanids (ERI) – 03:00 (045) -10   Velocity 66km/sec
Northern Hemisphere – 1 per hr   Southern Hemisphere – 1 per hour

Perseids (PER) – 03:12 (048) +58   Velocity 61km/sec
Northern Hemisphere – 40 per hr  Southern Hemisphere – 10 per hour

Alpha Triangulids (ATR) – 03:16 (049) +37   Velocity 67km/sec
Northern Hemisphere – <1 per hr Southern Hemisphere – <1 per hour

Clear Skies!
Robert Lunsford
American Meteor Society

Meteor Activity Outlook for August 4-10, 2012

The following is a slightly edited version of Bob Lunsford’s excellent weekly summary of meteor activity. The original version can be found at the American Meteor Society’s site.

Meteor activity kicks into high gear in August as seen from the northern hemisphere. The main reason for all this activity is the Perseid shower that peaks on August 12. This shower is active most of the month and remains above the level of the sporadic background for a week centered on August 12. The sporadic activity is also near maximum as seen from the northern hemisphere and is now more than double the rates from just three months ago. As seen from south of the equator, meteor rates are still decent but falling rapidly. The sporadic rates continue their downward slide and the Perseid radiant does not rise high into the sky as seen in the southern hemisphere so rates from this shower are greatly reduced when compared to the northern hemisphere.

During this period the moon reaches its last quarter phase on Thursday August 9th. This weekend the bright waning gibbous moon will rise during the late evening hours and will effectively ruin the sky for meteor watching the remainder of the night. The estimated total hourly rates for evening observers this week is near four for observers located in the northern hemisphere and two for observers south of the equator. For morning observers the estimated total hourly rates should be near fifteen for those located in the mid-northern hemisphere (45 N) and ten for those viewing from the mid-southern hemisphere (45 S). Locations between these two extremes would see activity between the listed figures. These rates assume that you are watching from rural areas away from all sources of light pollution. 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 during this period due to the intense moonlight.

The list below presents a summary of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning August 4/5, but may be used all week. The full descriptions of each radiant will continue next week when the moon becomes less of a nuisance to observers.

Kappa Cygnids (KCG) – 18:06 (274) +46   Velocity 23km/sec
Northern Hemisphere – <1 per hr    Southern Hemisphere – <1 per hour

Alpha Capricornids (CAP) – 20:36 (309) -09   Velocity 25km/sec
Northern Hemisphere – 1 per hr    Southern Hemisphere – 1 per hour

Antihelions (ANT) – 21:40 (325) -12   Velocity 30km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – 1 per hour

Delta Aquariids (SDA) – 22:42 (346) -14   Velocity 42km/sec
Northern Hemisphere – 2 per hr   Southern Hemisphere – 3 per hour

Piscids Austrinids (PAU) – 23:12 (348) -27   Velocity 35km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – 1 per hour

Perseids (PER) – 02:28 (037) +56   Velocity 61km/sec
Northern Hemisphere – 6 per hr   Southern Hemisphere – 3 per hour

Alpha Triangulids (ATR) – 02:40 (040) +37   Velocity 67km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

Eta Eridanids (ERI) – 02:52 (043) -13   Velocity 64km/sec
Northern Hemisphere – <1 per hr   Southern Hemisphere – <1 per hour

Clear Skies!
Robert Lunsford
American Meteor Society

 

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