Meteor Activity Outlook for December 24-30, 2011

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.

No matter where you live, the first half of December provides some of the best meteor activity of the year. Unfortunately in 2011, the moon will spoil much of this activity as I reaches its full phase on the 10th. In the northern hemisphere the sporadic rates are still strong plus you can also count on strong activity from the Geminids, which peak on December 14. There are also several minor radiants that add a few meteors each hour. All of these centers of activity are located high in the sky during the early morning hours this time of year. Much of the activity mentioned above can also be seen from the southern hemisphere. While the sporadic rates are not as strong as those seen from the north, they are stronger than the previous months and heading for a maximum in February. The warm, but short summer nights south of the equator make for some great viewing as long as the moon does not interfere.

During this period the moon reaches it new phase on Saturday December 24th. At this time the moon will be located near the sun and will be invisible at night. As the week progresses the waxing crescent moon will enter the evening sky but will not interfere with meteor observing as it is thin and will set long before the active morning hours arrive. The estimated total hourly rates for evening observers this week is near four as seen from the northern hemisphere and three as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near fifteen as seen from mid-northern latitudes and eight from mid-southern 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.

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 December 24/25. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following showers are expected to be active this week:

Now that particles produced by comet 2P/Encke are no longer encountering the Earth, the Taurid showers for 2011 are over and we resume reporting activity from the Antihelion (ANT) radiant. This is not a true radiant but rather activity caused by the Earth’s motion through space. As the Earth revolves around the sun it encounters particles orbiting in a prograde motion that are approaching their perihelion point. They all appear to be radiating from an area near the opposition point of the sun, hence the name Antihelion. These were once recorded as separate showers throughout the year but it is now suggested to bin them into a category separate from true showers and sporadics. This radiant is a very large oval some thirty degrees wide by fifteen degrees high. Activity from this radiant can appear from more than one constellation. The position listed here is for the center of the radiant which is currently located at 07:04 (106) +22. This position lies in central Gemini, four degrees west of the fourth magnitude star Wasat (Delta Geminorum). Antihelion activity may also appear from Monoceros, northeastern Orion, Canis Minor, or Cancer. This radiant is best placed near midnight local standard time (LST), when it lies on the meridian and is located highest in the sky. Rates at this time should be near two per hour as seen from the northern hemisphere and one per hour from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.

The December Leonis Minorids (DLM) are active from a radiant located at 11:04 (166) +28. This position lies in eastern Leo Minor, six degrees northwest of the third magnitude star Zosma (Delta Leonis). These meteors are best seen near 0500 local standard time (LST) when the radiant lies highest above the horizon. This shower peaked on December 20th so current rates would be near two per hour as seen from the northern hemisphere and less than one per hour as seen from south of the equator. At 64 km/sec. the December Leonis Minorids produce mostly swift meteors.

The last of the Ursids (URS) may be seen this weekend from a radiant located at 14:40 (220) +75. This position lies in eastern Ursa Minor, two degrees north of the second magnitude star Kochab (Beta Ursa Minoris). These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. This shower is not well seen from the southern hemisphere. Maximum activity is on Friday December 23th, so hourly rates this weekend would probably be less than one. On the morning of maximum, hourly rates of between 5-10 Ursids may be seen. At 33 km/sec. the Ursids produce mostly medium-slow meteors.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately eleven 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 seven 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 condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

Shower Name                 RA     DEC   Vel     Rates
                                         km/s   NH    SH
ANT Antihelions           07h 04m  +22    30     2     1
DLM Dec Leonis Minorids   11h 04m  +28    64     2     1
URS Ursids                14h 40m  +75    33    <1    <1

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a dark site
NH - Northern Hemisphere
SH - Southern Hemisphere

Meteor Activity Outlook for December 17-23, 2011

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.

No matter where you live, the first half of December provides some of the best meteor activity of the year. Unfortunately in 2011, the moon will spoil much of this activity as I reaches its full phase on the 10th. In the northern hemisphere the sporadic rates are still strong plus you can also count on strong activity from the Geminids, which peak on December 14. There are also several minor radiants that add a few meteors each hour. All of these centers of activity are located high in the sky during the early morning hours this time of year. Much of the activity mentioned above can also be seen from the southern hemisphere. While the sporadic rates are not as strong as those seen from the north, they are stronger than the previous months and heading for a maximum in February. The warm, but short summer nights south of the equator make for some great viewing as long as the moon does not interfere.

During this period the moon reaches it last quarter phase on Sunday December 18th. The half illuminated moon is still very bright and must be kept out of your field of view for successful meteor observations. During this period, the evening hours, which are unfortunately much less active with meteors, will be completely free of any interfering moonlight.  As the week progresses the moon will wane in phase and will rise approximately forty-five minutes later with each passing night. With this scenario, viewing conditions during the more active morning hours will improve with each passing night. The estimated total hourly rates for evening observers this week is near five as seen from the northern hemisphere and three as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near twelve two as seen from mid-northern latitudes and eight from mid-southern 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. Morning rates are 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 December 17/18. These positions do not change greatly day to day so the listed coordinates may be used during this entire period..

The following showers are expected to be active this weekNow that particles produced by comet 2P/Encke are no longer encountering the Earth, the Taurid showers for 2011 are over and we resume reporting activity from the Antihelion (ANT) radiant. This is not a true radiant but rather activity caused by the Earth’s motion through space. As the Earth revolves around the sun it encounters particles orbiting in a prograde motion that are approaching their perihelion point. They all appear to be radiating from an area near the opposition point of the sun, hence the name Antihelion. These were once recorded as separate showers throughout the year but it is now suggested to bin them into a category separate from true showers and sporadics. This radiant is a very large oval some thirty degrees wide by fifteen degrees high. Activity from this radiant can appear from more than one constellation. The position listed here is for the center of the radiant which is currently located at 06:36 (099) +23. This position lies in western Gemini, three degrees southwest of the third magnitude star Epsilon Geminorum. Antihelion activity may also appear from eastern Taurus, northeastern Orion, or southern Auriga. This radiant is best placed near midnight local standard time (LST), when it lies on the meridian and is located highest in the sky. Rates at this time should be near two per hour as seen from the northern hemisphere and one per hour from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.

The last of the Monocerotids (MON) may be seen this weekend from a radiant located at 07:03 (106) +07. This position lies on the Monoceros/Canis Minor border, ten degrees west of the brilliant zero magnitude star Procyon (Alpha Canis Minoris). Rates would be less than one per hour no matter your location. The Monocerotids are best seen near 0100 LST when the radiant lies highest above the horizon. At 41 km/sec. the Monocerotids produce mostly meteors of medium velocity.

The last of the Sigma Hydrids (HYD) may be seen this weekend from a radiant located at 08:54 (134) +00. This position lies in western Hydra, five degrees south of the third magnitude star Zeta Hydrae. Rates would be less than one per hour no matter your location. The Sigma Hydrids are best seen near 0300 LST when the radiant lies highest above the horizon. At 61 km/sec. the Sigma Hydrids produce mostly swift meteors.

The December Leonis Minorids (DLM) are active from a radiant located at 10:39 (160) +31. This position lies in eastern Leo Minor, ten degrees northeast of the third magnitude star Zeta Leonis. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. This shower peaks on December 20th so current rates would be near one per hour as seen from the northern hemisphere and less than one per hour as seen from south of the equator. At 64 km/sec. the December Leonis Minorids produce mostly swift meteors.

The Coma Berenicids (COM) are active from a radiant located at 11:51 (178) +18. This position actually lies in eastern Leo, two degrees north of the second magnitude star Denebola (Beta Leonis). These meteors are best seen near 0600 LST when the radiant lies highest above the horizon. This shower peaked on December 16th so current rates would be near one per hour no matter your location. This week will be your only opportunity to see these meteors as the shower will be over by the 23rd. At 65 km/sec. the Coma Berenicids produce mostly swift meteors.

Activity from the  Ursids (URS) may begin to appear this weekend from a radiant located at 13:58 (210) +76. This position lies in eastern Ursa Minor, fifteen degrees east of the second magnitude star Kochab (Beta Ursa Minoris). It must be remembered that the length of degrees are smaller in high declinations so the radiant is actually closer to this star than these figures inply. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. This shower is not well seen from the southern hemisphere. Maximum activity is not expected until Friday December 23th, so current hourly rates would probably be less than one. On the morning of maximum, hourly rates of between 5-10 Ursids may be seen. At 33 km/sec. the Ursids produce mostly medium-slow meteors.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately eight 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. Morning rates are reduced due to moonlight.:

The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

Shower Name                 RA     DEC   Vel     Rates
                                         km/s   NH    SH
ANT Antihelions           06h 36m  +23    30     2     1
MON Monocerotids          07h 03m  +07    41    <1    <1
HYD Sigma Hydrids         08h 54m  +00    61    <1    <1
DLM Dec Leonis Minorids   10h 39m  +31    64     1     1
COM Coma Berenicids       11h 51m  +18    65     1     1
URS Ursida                13h 58m  +76    33    <1    <1

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a dark site
NH - Northern Hemisphere
SH - Southern Hemisphere

Meteor Activity Outlook for December 3-9, 2011

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.

No matter where you live, the first half of December provides some of the best meteor activity of the year. Unfortunately in 2011, the moon will spoil much of this activity as I reaches its full phase on the 10th. In the northern hemisphere the sporadic rates are still strong plus you can also count on strong activity from the Geminids, which peak on December 14. There are also several minor radiants that add a few meteors each hour. All of these centers of activity are located high in the sky during the early morning hours this time of year. Much of the activity mentioned above can also be seen from the southern hemisphere. While the sporadic rates are not as strong as those seen from the north, they are stronger than the previous months and heading for a maximum in February. The warm, but short summer nights south of the equator make for some great viewing as long as the moon does not interfere.

During this period the moon waxes from half illuminated to nearly full by the end of the period. This weekend the waxing gibbous moon will set during the early morning hours, allowing a few hours of observing under dark skies between moon set and the start of morning twilight. The estimated total hourly rates for evening observers this week is near three as seen from the northern hemisphere and two as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near twenty two as seen from mid-northern latitudes and eighteen from mid-southern 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 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 December 3/4. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The following showers are expected to be active this week:

The December Phoenicids (PHO) are a periodic shower that rarely produces noticeable activity. The only impressive display produced by this shower occurred in 1956 when ZHR’s were near 100. Peak activity occurs on December 6. Little activity is expected away from the peak night. The radiant is currently located at 00:46 (016) -53. This position lies in eastern Phoenix, five degrees northwest of the first magnitude star Archernar (Alpha Eridani). These meteors are best seen near 2000 (8pm) local standard time (LST), when the radiant lies highest above the horizon in a dark sky. Due to the southerly declination of the radiant, this shower is not visible north of the northern tropical areas. The deep southern hemisphere has the best chance of seeing any activity. At 22 km/sec. the Phoenicids produce very slow meteors.

The last of the Northern Taurids (NTA) for 2011 will be seen this week from a large radiant centered at 05:09 (077) +26. This position lies in eastern Taurus, five degrees southwest of the second magnitude star El Nath (Beta Tauri). The radiant is best placed near midnight LST, when it lies highest above the horizon. Since the radiant is large, Northern Taurid meteors may also appear to come from southern Auriga, southeastern Perseus, northern Orion, and western Gemini as well as Taurus. Meteors from the Northern Taurids strike the atmosphere at 29km/sec., which would produce meteors of slow velocity. Expected rates would be near two per hour, no matter your location.

The November Orionids (NOO) were recently discovered by Sirko Molau and Jueregen Rendtel by analyzing video data from the IMO network. For years this radiant was lost in the maze of radiants active this time of year. Due to the low activity, visual observers were unable to detect this shower. This shower is active from November 18 through December 9. Maximum activity occurred on November 30. Once you know the radiant in advance, this shower is actually quite noticeable, producing an average of two shower members per hour near maximum. The radiant is currently located at 06:16 (094) +15. This position lies in northeastern Orion, seven degrees northeast of the orange first magnitude star Betelgeuse (Alpha Orionis). These meteors are best seen near 0100 LST when the radiant lies on the meridian and highest above the horizon. At 44 km/sec. the November Orionids produce mostly medium velocity meteors.

The Monocerotids (MON) are active from December 7th through the 18th. Peak activity occurs on December 8th. On the night of maximum activity the radiant is located at 06:37 (099) +08. This position lies in northern Monoceros, eight degrees south of the second magnitude star Alhena (Gamma Geminorum). Rates at maximum should be near one per hour no matter your location. The Monocerotids are best seen near 0100 LST when the radiant lies highest above the horizon. At 41 km/sec. the Monocerotids produce mostly meteors of medium velocity.

Geminid (GEM) activity begins this weekend from a radiant located at 06:55 (104) +34. This position lies in northern Gemini, near the fourth magnitude star Theta Geminorum. Expected rates this weekend would only be near one per hour as maximum is still ten days away. Although Geminid meteors can be seen all night long, they are best seen near 0200 LST when the radiant lies highest above the horizon. This shower peaks on the night of December 14, when rates can surpass 60 shower members per hour in moonless skies. Unfortunately this year there will be a bright moon and observers will be limited to seeing no more than 20-30 meteors per hour. Geminid activity can be seen from the southern hemisphere but at much reduced rate. As seen from south of the equator, Geminid activity could only be seen for a few hours before and after 0200 LST. At 35 km/sec. the Geminids produce mostly meteors of medium velocity.

The Puppid-Velids (PUP) are a vast complex of weak radiants located in the constellations of Puppis and Vela. Visual plots and photographic studies have revealed many radiants in this area during November and December. The combined strength of these radiants can produce a ZHR of ten. Actual hourly rates will be much less unless you happen to be observing from the deep Southern Hemisphere. Activity from this source begins around December 1st. The center of this activity is currently located at 08:05 (121) -45. This position lies in western Vela, two degrees north of the second magnitude star Gamma Velorum. Peak rates occur near December 7. These meteors are best seen near 0300 LST when the radiant lies highest above the horizon in a dark sky. Observers located in the Southern Hemisphere have an advantage viewing this shower as the radiant will rise higher into their sky allowing more activity to be seen. Since the radiant lies low in the south for most northern hemisphere observers, meteors seen from north of the equator tend to be long in length and long-lasting. At 40 km/sec. the Puppid-Velids produce meteors of average velocity.

The Sigma Hydrids (HYD) are active from November 26 through December 20. Maximum activity occurs on December 6 from a radiant located at 08:11 (122) +03. This position lies on the Hydra/Canis Minor border, seven degrees southeast of the brilliant zero magnitude star Procyon (Alpha Canis Minoris). These meteors are best seen near 0300 LST when the radiant lies highest above the horizon. Current rates would be near two per hour no matter your location. At 61 km/sec. the Sigma Hydrids produce mostly swift meteors.

Activity from the December Leonis Minorids (DLM) begin next week from a radiant located at 09:56 (149) +37. This position lies in central Leo Minor, seven degrees northeast of the fourth magnitude star Alpha Lyncis. These meteors are best seen near 0500 LST when the radiant lies highest above the horizon. This shower peaks on December 20th so current rates would be near one per hour as seen from the northern hemisphere and less than one per hour as seen from south of the equator. At 64 km/sec. the December Leonis Minorids produce mostly swift meteors.

Another shower verified by video means are the Psi Ursa Majorids (PSU). This shower is active from November 29-December 13 with maximum activity occurring on December 5. On Tuesday the radiant is located at 11:07 (167) +43. This position lies in southern Ursa Major, one degree south of the third magnitude star Psi Ursae Majoris. This area of the sky is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates would most likely be less than one per hour. At 61km/sec., the average Psi Ursa Majorid meteor would be swift.

Another shower verified by video means are the December Kappa Draconids (KDR). This shower is active from November 30-December 6 with maximum activity occurring on December 3rd. On the night of maximum the radiant will be located at 12:24 (186) +70. This position lies in extreme western Draco, close to the faint star Kappa Draconis. While the radiant lies above the horizon all night for most of the northern hemisphere, it is best placed during the last hour before dawn, when it lies highest above the horizon in a dark sky. Current rates would most likely be less than one per hour. At 43km/sec., the average December Kappa Draconid meteor would be of medium velocity.

Lastly, the December Alpha Draconids (DAD) are active beginning Sunday from a radiant located at 13:31 (203) +60. This position actually lies in northeastern Ursa Major, five degrees north of the second magnitude double star Mizar (Zeta Ursae Majoris). These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. This shower is not well seen from the southern hemisphere. Maximum activity is expected on Monday December 5th, but hourly rates would probably be less than one no matter your location. At 44 km/sec. the Alpha Draconids produce mostly medium speed meteors.

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 two 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 one per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced due to moonlight.

The list below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning.

Shower Name                 RA     DEC   Vel     Rates
                                         km/s   NH    SH
PHO Dec Phoenicids        00h 46m  -52    18    <1    <1
NTA Northern Taurids      05h 09m  +26    29     2     2
NOO November Orionids     06h 16m  +15    44     2     2
MON Monocerotids          06h 37m  +08    41     1     1
GEM Geminids              06h 55m  +34    35     1     1
PUP Puppids-Velids        08h 05m  -45    40    <1     2
HYD Sigma Hydrids         08h 11m  +03    61     2     2
DLM Dec Leonis Minorids   09h 56m  +37    64     1    <1
PSU Psi Ursa Majorids     11h 07m  +43    61    <1    <1
KDR Dec Kappa Draconids   12h 24m  +70    43    <1    <1
DAD Dec Alpha Draconids   13h 31m  +60    44    <1    <1

RA - Right Ascension
DEC - Declination
Vel - Velocity relative to Earth (in km per sec)
Rates - Rate of visible meteors per hour from a dark site
NH - Northern Hemisphere
SH - Southern Hemisphere
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