Dec 25/26 Meteors

Well, it has been way too long… For long time followers of the blog, I am well. My long absence from blogging was due to mostly good things (wonderful twin boys, a heavy work load at the OSIRIS-REx asteroid mission and the usual family life activities that comes with new children and a new home).

The one bad issue that kept me from blogging (at least video meteor data) was the inoperability of my cameras after moving to my new home. For some reason all 4 of my cameras ceased working properly when I tried to re-start my video network. After 2 years of buying new cameras, cables, connectors and such, I finally found the culprit. The cameras did not like the power coming out of the house and required new AC adaptors to work.

In short, my SALSA3 camera (Watec 902H2 Ultimate + 3.8mm f/0.8 lens) is back up and running after 2+ years of downtime and I hope to be posting more regularly in the future.

Last night was my first successful first night and resulted in the capture of 34 meteors. We are currently between major showers (the Geminids of mid-Dec and the Quadrantids of early January) so most of the meteors were sporadics and part of a few of the active minor showers.

Obs  Date(UT)      Time    TOT SPO ANT AHY COM DLM DSV URS
SAL  2013-12-26   08h 51m   34  24  3   3   0   2   2   0
SAL - SALSA3 camera in Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
AHY - Alpha Hydrids
COM - Comae Berenicids
DLM - December Leonis Minorids
DSV - December Sigma Virginids
URS - Ursids

Meteor Activity Outlook for December 22-28, 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.

No matter where you live, the first half of December provides some of the best meteor activity of the year. This activity will be tempered by a bright moon during the first week of the month. The next two weeks are moon-free and offer the meteor observer ample opportunities to view some celestial fireworks. 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 13. 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 its full  phase on Friday December 28th. At this time the moon is located opposite the sun and will remain in the sky all night long. This weekend the waxing gibbous moon will set during the early morning hours and will allow several hours of dark sky viewing before dawn arrives. As the week progresses this window of dark skies shrinks until late in the week when the moon will remain above the horizon all night long. The estimated total hourly meteor rates for evening observers this week is near three for observers located at mid-northern latitudes and two for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near twenty four from the mid-northern hemisphere and ten 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. Rates are reduced during the evening hours 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 December 22/23. 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 the activity from particles produced by comet 2P/Encke has ceased encountering the Earth, the Taurid showers for 2012 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 pro-grade 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 their 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 06:56 (104) +22. This position lies in central Gemini, four degrees southeast of the third magnitude star Mebsuta (Epsilon Geminorum). Antihelion activity may also appear from eastern Taurus, northeastern Orion, Cancer, Canis Minor, Monoceros, or southern Auriga. This radiant is best placed near midnight local standard time (LST) when it lies on the meridian and is highest in the sky. Rates at this time should be near three per hour as seen from the northern hemisphere and two 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 10:52 (163) +30. This position lies in central Leo Minor, approximately four degrees southwest of the third magnitude star Alula Borealis (Nu Ursae Majoris). These meteors are best seen near 0400 LST when the radiant lies highest above the horizon. This shower peaked on December 17th 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 Coma Berenicids (COM) are best seen from December 23 through January 2. Maximum activity occurs on January 1st when this shower is the fourth strongest in the sky. The current radiant position lies at 11:46 (176) +18. This position actually lies eastern Leo, four degrees northwest of the second magnitude star Denebola (Beta Leonis). Current hourly rates would most likely be less than one shower member per hour no matter your location. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 69 km/sec. The Coma Berenicids would produce mostly swift meteors.

IMO Shower #247 seems to be a northern counterpart of the Coma Berenicids. It shares the same right ascension (celestial longitude) as the Coma Berenicids but is located nearly twenty degrees further north. The activity period is shorter than the Coma Berenicids as it is best seen from December 24-27, with maximum activity occurring on the 24th. Maximum rates would be near one per hour as seen from the northern hemisphere and less than one as seen from south of the equator. At maximum activity the radiant is located at 12:00 (180) +37, which is located in a remote area of southeastern Ursa Major. The nearest bright star would be third magnitude star Alula Borealis (Nu Ursae Majoris), which is located ten degrees to the southwest. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 66 km/sec. IMO Shower #247  would produce mostly swift meteors.

Studies by Sirko Molau and Juergen Rendtel of the IMO discovered an active radiant in Virgo this time of year. The December Sigma Virginids (DSV) are active through most of December and the first week of January. Visual observers have their best chance at catching these meteors from December 17 through January 1st. Maximum activity occurs on December 31st. Current rates would most likely be less than one shower member no matter you location. The current radiant location is at 13:52 (208) +04 which place it in northern Virgo some four degrees northwest of the fourth magnitude star Tau Virginis. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 69 km/sec. the December Sigma Virginids would produce mostly swift meteors.

The Ursids (URS) peak on the morning of December 22 from a radiant located at 14:32 (218) +75. This position lies in eastern Ursa Minor, just northeast 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. Due to the extreme northerly location meteors from this shower are not visible from the southern hemisphere. On the morning of maximum, hourly rates of between 5-10 Ursids may be seen during the late morning hours. At 33 km/sec. the Ursids produce mostly medium-slow meteors.

The Quadrantids (QUA) begin to appear in weak numbers on the morning of December 26th. The radiant is then located near 15:04 (226) +53, which places it in northern Bootes, eight degrees southwest of the third magnitude star Edasich (Iota Draconis). Rates at this time would be less than one shower member per hour no matter your location. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 42 km/sec. the Quadrantids would produce mostly meteors of medium velocity.

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 two 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 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.

Antihelions (ANT) – 06:56 (104) +22   Velocity – 30km/sec.
Northern Hemisphere – 3 per hr.   Southern Hemisphere – 2 per hr

December Leonis Minorids (DLM) – 10:52 (163) +30   Velocity – 64km/sec.
Northern Hemisphere – 2 per hr.   Southern Hemisphere – <1 per hr

Coma Berenicids (COM) – 11:46 (176) +18   Velocity – 69km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

IMO #247  – 12:00 (180) +37   Velocity – 66km/sec.
Northern Hemisphere – 1 per hr.   Southern Hemisphere – <1 per hr

Dec. Sigma Virginids (DSV) – 13:52 (208) +04  Velocity – 44km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr

Ursids (URS) – 13:58 (210) +76   Velocity – 33km/sec.
Northern Hemisphere – 7 per hr. Southern Hemisphere – 0 per hr

Quadrantids (QUA) – 15:04 (226) +53    Velocity – 42km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr

Clear Skies!
Robert Lunsford
American Meteor Society

Meteor Activity Outlook for December 15-21, 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.

No matter where you live, the first half of December provides some of the best meteor activity of the year. This activity will be tempered by a bright moon during the first week of the month. The next two weeks are moon-free and offer the meteor observer ample opportunities to view some celestial fireworks. 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 13. 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 its first quarter phase on Wednesday December 19th. At this time the moon is located ninety degrees east of the sun and will set near midnight local standard time (LST). This weekend the waxing crescent moon will set during the early evening hours and will not cause any problems to meteor observers. As the week progresses the moon will set later and later, but will still allow unhampered views of the more active morning sky. 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 thirty from the mid-northern hemisphere and sixteen 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. Rates are slightly reduced during the evening hours 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 December 15/16. 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 the activity from particles produced by comet 2P/Encke has ceased encountering the Earth, the Taurid showers for 2012 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 their 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 06:28 (097) +23. This position lies in western Gemini near the third magnitude star Mebsuta (Epsilon Geminorum). Antihelion activity may also appear from eastern Taurus, northeastern Orion, or southern Auriga. This radiant is best placed near midnight LST when it lies on the meridian and is highest in the sky. Rates at this time should be near three per hour as seen from the northern hemisphere and two 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 Monocerotids (MON) are active from December 7th through the 18th. Peak activity occurred on December 8th so current rates should be less than one per hour no matter your location. The radiant is located at 07:00 (105) +07. This position lies in eastern Monoceros, ten degrees east of the zero magnitude star Procyon (Alpha Canis Minoris).  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 Geminids (GEM) reached maximum activity on Thursday evening/Friday morning December 13/14. This weekend will be your last good opportunity to see any Geminids in 2012 as activity ceases next week. The radiant is currently located at 07:40 (115) +32, which places it in northeastern Gemini, just east of the second magnitude star Castor (Alpha Geminorum). Rates this weekend, when the radiant lies high in the sky, would be 20-40 per hour (depending on your viewing conditions) on the night of 14/15 and 10-20 per hour on the night of 15/16. Geminid meteors strike the atmosphere at 35km/sec, which will produce meteors of medium-slow velocity.

The Sigma Hydrids (HYD) are active from November 26 through December 20. Maximum activity occurred on December 6, so current rates would be near one per hour no matter your location. The radiant is located at 08:47 (132) +01. This position lies in western Hydra, just south of the group of fourth magnitude stars that make up the “head” of the water serpent. These meteors 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 10:32 (158) +32. This position lies in central Leo Minor, approximately 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 17th 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.

On the nights of December 19-21, weak activity from the Rho Leonids  (RLE) may be noticed. Sirko Molau and Juergen Rendtel of the IMO have found the actual activity range is December 17-23, but away from the nights mentioned above, the display is very weak. Previous radiants for this shower were further north. Video results give a position at maximum near 10:34 (159) -05. This actually places it in central Sextans, some fifteen degrees southeast of the first magnitude star Regulus (Alpha Leonis). Rates could approach one shower member per hour during the last few hours before dawn on the nights previously mentioned. At 69 km/sec. the Rho Leonids would produce mostly swift meteors.

On the nights of December 15/16 and 16/17, weak activity from the Virgo/Corvus border may be noticed. This currently unnamed source is active from December 5-27, but incredibly weak except for the two nights mentioned above. The exact radiant position for IMO Shower #239 is 12:52 (193) -11. This places it some ten degrees west of the first magnitude star Spica (Alpha Virginis). At 70 km/sec. These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. IMO Shower #239 would produce mostly swift meteors.

Another shower found by Sirko Molau and Juergen Rendtel of the IMO are the December Sigma Virginids (DSV). This radiant is active through most of December and the first week of January. Visual observers have their best chance at catching these meteors from December 17 through January 1st. Maximum activity occurs on December 31st. The current radiant location is 13:32 (203) +05, which places it in northern Virgo some five degrees north of the third magnitude star Heze (Zeta Virginis). These meteors are best seen during the last dark hour before dawn, when the radiant lies highest above the horizon in a dark sky. At 69 km/sec. the December Sigma Virginids would produce mostly swift meteors.

Activity from the Ursids (URS) should begin to appear during the mid-week period 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 imply. 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 Saturday December 22th, so current hourly rates this week 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.

Lastly, the December Alpha Draconids (DAD) are active from December 4-16. Maximum activity occurred on December 5. The radiant is currently located at 14:08 (212) +57. This position actually lies in northeastern Ursa Major, ten degrees northeast 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. Expected hourly rates would 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 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. Evening rates are slightly 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.

Antihelions (ANT) – 06:28 (097) +23   Velocity – 30km/sec.
Northern Hemisphere – 3 per hr.   Southern Hemisphere – 2 per hr

Dec. Monocerotids (MON) – 07:00 (105) +07   Velocity – 41km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

Geminids (GEM) -07:40 (115) +32   Velocity – 35km/sec.
Northern Hemisphere – 10 per hr.   Southern Hemisphere – 5 per hr

Sigma Hydrids (HYD) -08:47 (132) +01   Velocity – 61km/sec.
Northern Hemisphere – 1 per hr.   Southern Hemisphere – 1 per hr

December Leonis Minorids (DLM) – 10:32 (158) +32   Velocity – 64km/sec.
Northern Hemisphere – 2 per hr.  Southern Hemisphere – <1 per hr

Rho Leonids (RLE) – 10:34 (159) -05   Velocity – 69km/sec.
Northern Hemisphere – 1 per hr.  Southern Hemisphere – 1 per hr

IMO #239  – 12:52  (193) -11   Velocity – 69km/sec.
Northern Hemisphere – 2 per hr. Southern Hemisphere – <1 per hr

Dec. Sigma Virginids (DSV) – 13:32 (203) +05   Velocity – 44km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr

Ursids (URS)  – 13:58 (210) +76    Velocity – 33km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr

December Alpha Draconids (DAD) – 14:08 (212) +57   Velocity – 44km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr

Clear Skies!
Robert Lunsford
American Meteor Society

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 18-24, 2010

The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook 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. 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 January. 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 its full phase on Tuesday December 21st. At this time the moon lies opposite the sun and is above the horizon all night long from most locations. This is the worst time to attempt to view meteor activity as the bright moonlight will obscure all but the brightest meteors. The estimated total hourly rates for evening observers this week is ~3 from the northern hemisphere and ~2 for observers south of the equator. For morning observers the estimated total hourly rates should be ~10 from the northern hemisphere and ~9 as seen from the 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. 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 December 18/19. 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 detailed descriptions will be continued next week when the moonlight is not as intense.

Shower Name                 RA     DEC   Vel     Rates
                                         km/s   NH    SH
ANT Antihelions           06h 40m  +23    30     2     2
MON Monocerotids          07h 08m  +07    41    <1    <1
GEM Geminids              07h 56m  +31    35     1     1
HYD Sigma Hydrids         08h 56m  +00    61    <1    <1
DLM Dec Leonis Minorids   10h 44m  +31    71     1    <1
COM Coma Berenicids       11h 48m  +18    65     2    <1
URS Ursids                14h 12m  +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

Dec 22/23 Meteors

A relatively strong (at least for AZ) storm moved through the region over the past few nights. Similar to the storm from a few weeks back, one of my cameras again suffered from condensation in its lens. The problem is not the lenses but my all-weather enclosure which is no longer “all-weather”. For the time being, I’ll be down to a single camera again until after the holidays when I’ll have time to fix the faulty enclosure.

The aforementioned storm shut me out for a 2nd straight night. Luckily the storm had moved far enough to the east to allow Bob to get some good data.

Bob’s notes from the night of Dec 22/23 : “Clouds and rain prevented any useful video observations on the 22nd, which was bad timing as this was the maximum night for the Ursid meteor shower. The skies cleared near midnight last night and remained clear the remainder of the morning. Meteor rates varied significantly without any rhyme or reason. No Ursids remained from the maximum that occurred the previous morning.”

Due to the holidays, postings will be sparse. If anything exciting happens I’ll put something out. Until then, Merry Christmas and Happy New Year!

Obs  Date(UT)      Time    TOT SPO ANT DLM URS
TUS  2009-12-23   00h 00m  No meteors - Clouds/Rain
SDG  2009-12-23   05h 42m   43  36  4   3   0 

TUS - Camera in Tucson operated by Carl Hergenrother
SDG - Camera in San Diego operated by Bob Lunsford
TotTime - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
DLM - December Leonis Minorids
URS - Ursids
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