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 15/16 Meteors

Two nights ago my cameras detected a total of 206 Geminids (some were probably duplicates). One night ago the total number dropped to 32 Geminids. Last night the number of Geminids was a whopping 2. It’s amazing how quickly the Geminids can fall off after their peak. It is safe to say that the 2010 Geminids are pretty much over for visual observers.

Last night marked SALSA3′s 82nd straight night with a meteor detection. With it currently raining and more forecast for tonight the streak may very well end at 82.

Obs  Date(UT)      Time    TOT SPO ANT GEM HYD DAD DLM MON COM
SAL3 2010-12-16   05h 54m   19  10  1   0   2   1   3   1   1
ALLS 2010-12-16   04h 58m   19  12  1   2   1   1   2   0   0
HERM 2010-12-16   11h 31m   9   7   0   1   1   -   -   0   0

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
VISH - Visual observations from Hermosillo (Salvador Aguirre)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
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   
GEM - Geminids
HYD - Sigma Hydrids
DAD - December Alpha Draconids
DLM - December Leonis Minorids
MON - Monocerotids

Dec 14/15 Meteors (night after the Geminids peak)

What a difference 24 hours makes! Only a day removed from the Geminids peak and rates have crashed to a fraction of their peak. During the past 5 nights SALSA3 detected 12, 22, 69, 124 and now 20 Geminids. This is a characteristic of the Geminids in that the post-peak rates fall off much more rapidly than the pre-peak increase.

The night of Dec 14/15 marked the 81st consecutive nights that SALSA3 detected a meteor. As of right now, there is a good chance that it is clear enough for night 82 to produce a few meteors. Tomorrow night will be iffy as a storm, our first in 2 months, is forecast to bring rain and clouds to the area. Will the streak survive? We’ll have to wait and see.

Obs  Date(UT)      Time    TOT SPO ANT GEM HYD PUP DAD DLM MON COM
SAL3 2010-12-15   12h 10m   53  20  5   20  1   1   1   1   2   2
ALLS 2010-12-15   12h 38m   40  15  4   11  3   0   1   3   1   2
HERM 2010-12-15   11h 50m   28  15  2   10  0   1   -   -   -   0
VISM 2010-12-15   02h 00m   37  0   1   28  3   1   -   -   1   3 (LM = +5.7 to +6.0)

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
VISH - Visual observations from Hermosillo (Salvador Aguirre)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
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   
GEM - Geminids
HYD - Sigma Hydrids
PUP - Puppids-Vellids
DAD - December Alpha Draconids
DLM - December Leonis Minorids
MON - Monocerotids

Dec 13/14 Meteors and the Geminids Peak

The Geminids did not dissapoint! Though the IMO ZHR Live page doesn’t seem to be updating observations made by myself and Salvador show ZHRs that equaled or even exceeded the expected value of 120. Over the course of about 3.33 hours I averaged about 1 meteor per minute under skies that range from a limiting magnitude of +5.0 (when the Moon was still up) to +5.7 (before the break of dawn).

For my SALSA3 and Sentinel cameras it was a record-setting night. The previous single night record for SALSA3 (and its 2 predecessors) was 124 meteors during this year’s Perseids peak. Last night SALSA3 detected 124 Geminids! Add in another 35 non-Geminids and the total for he night was 159 meteors. The near-allsky Sentinel also broke its previous record set during this year’s Perseids by catching 123 meteors of which 84 were Geminids.

The video below contains all 159 meteors detected by SALSA3. It starts in the evening where you can catch a short glimpse of the Moon as it quickly moves out of the frame. Note the top of one of my trees illuminated by Christmas lights for the first few meteors. Though not all of the meteors are Geminids most are and it is fun to watch them radiate from the twin stars of Castor and Pollux.

The next plot is a radiant plot. For every meteor detected my SALSA3, the MetRec software runs the path of the meteor back. Where the back tracks of related meteors cross is the radiant. It is obvious from the plot that most of last night’s meteors are related and radiated from an area near the bright star Castor.

Down in Hermosillo, Salvador spent almost 5 hours watching the Geminids and racked up a total of 308 meteors of which 272 were Geminids. This is in addition to his PARENI camera which also caught 75 meteors.

Obs  Date(UT)      Time    TOT SPO ANT GEM HYD PUP DAD DLM MON COM
SAL3 2010-12-14   12h 10m  159  22  7  124  2   0   2   1   0   1
ALLS 2010-12-14   12h 38m  123  24  9   84  1   1   0   1   2   1
HERM 2010-12-14   11h 42m   75  17  6   49  1   -   -   -   1   1
VIST 2010-12-13   03h 20m  199  31  -  168  -   -   -   -   -   - (LM=+5.0 to +5.7)
VISH 2010-12-13   04h 40m  308  12  3  272  8   4   -   -   5   4 (LM=+5.5 to +6.2)

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
VISH - Visual observations from Hermosillo (Salvador Aguirre)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
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   
GEM - Geminids
HYD - Sigma Hydrids
PUP - Puppids-Vellids
DAD - December Alpha Draconids
DLM - December Leonis Minorids
MON - Monocerotids

Geminids Peak – First Observing Session

The moon is still up, most of the neighbors still have their Christmas lights on full blast and the Geminid radiant is still on the low side and yet the Geminids are already putting on a great show.

During the hour between 10:48 pm (5:48 UT) and 11:48 pm (6:48 UT), I counted 43 meteors of which 35 were Geminids. All this under a rather bright +5.0 magnitude sky. The Geminids came in bunches with 6 seen over 2 minutes at one point (including 2 simultaneously) while earlier in the session nearly 6 minutes went by without a meteor. The best meteor of the night so far was not a Geminid but a -3 Sporadic.

I’ll try to get out there again after the Moon sets and the sky is a little darker.

Dec 12/13 Meteors (a night before the Geminids peak)

Make no mistake about it, the Geminids are back! Though much of the US is griped in either snow or bitter cold, the Mexican state of Sonora and the American states of Arizona and California are seeing warm temps and clear skies.

My SALSA3 camera picked up a total of 94 meteors with 69 of those id’d as Geminids. The near all-sky Sentinel camera saw 55 meteors with 32 being Geminids. Over in San Diego, Bob’s intensified camera caught many more with 171 Geminids seen out of a grand total of 241 meteors.

On the visual side, I was able to observe for ~1.5 hours last night under a +5.4 and +5.7 sky (+5.4 for my first session and +5.7 for my 2nd session). The +5.7 limiting magnitude was the darkest I’ve ever recorded from my home. Between the 2 sessions I spied 53 meteors with 35 being Geminids.

Down in Hermosillo, Salvador is blessed with even darker skies with a limiting magnitude of +6.2. Over 3.5 hours he caught 143 meteors with 104 being Geminids.

According to the IMO’s Live ZHR plot, the Geminids were producing a ZHR between 40 and 60 last night. Of course, if you live anywhere near civilization, your sky is bright and actual rates will  be much lower. For relatively dark Tucson actual hourly rates were closer to 20-30 per hour.

Tonight marks the peak of the Geminids and if history is any guide, rates should twice as high as last night. Remember the Moon will spoil the view early on so its better to wait till after midnight to observe.

Last night also marked SALSA3′s 79th consecutive night with a meteor detection.

Obs  Date(UT)      Time    TOT SPO ANT GEM HYD PSU PUP DAD DLM MON COM
SAL3 2010-12-13   12h 09m   94  15  2   69  3   0   0   0   1   2   2
ALLS 2010-12-13   12h 39m   55  9   2   32  5   1   0   0   4   0   2
SDG  2010-12-13   10h 23m  241  72  7  171  3   3   2   3   4   4   2
VIST 2010-12-13   01h 31m   53  18  -   35  -   -   -   -   -   -   - (LM=+5.4,5.7)
VISH 2010-12-13   03h 30m  143  14  4  104  7   -   4   -   -   7   3 (LM=+6.2)

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
VISH - Visual observations from Hermosillo (Salvador Aguirre)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
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   
GEM - Geminids
HYD - Sigma Hydrids
PSU - Psi Ursa Majorids
PUP - Puppids-Vellids
DAD - December Alpha Draconids
DLM - December Leonis Minorids
MON - Monocerotids

Meteor Activity Outlook for December 11-17, 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 first quarter phase on Sunday December 12th. At this time the moon lies ninety degrees east of the sun and sets near midnight local standard time (LST) for those located in the mid-northern latitudes. Later next week the waxing gibbous moon remains above the horizon most of the night making meteor observing difficult. The estimated total hourly rates for evening observers this week is ~8 from the northern hemisphere and ~2 for observers south of the equator. For morning observers the estimated total hourly rates should be ~45 from the northern hemisphere and ~20 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. Evening rates are reduced this week 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 11/12. 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:

Antihelions (ANT)

Now that the activity from particles produced by comet 2P/Encke has ceased encountering the Earth, the Taurid showers for 2010 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 06:12 (093) +23. This position lies in western Gemini near the fourth magnitude star Eta 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 ~3 per hour as seen from the northern hemisphere and ~2 per hour from south of the equator. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of slow velocity.

Monocerotids (MON)

The Monocerotids (MON) are active from December 7th through the 18th. Peak activity occurred on December 8th. The radiant is currently located at 06:48 (102) +08. This position lies in northwestern Monoceros halfway between the bright stars Betelgeuse (Alpha Orionis) and Procyon (Alpha Canis Minoris). Current rates should be ~1 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.

Geminids (GEM)

The Geminids (GEM) reach maximum activity on Monday evening/Tuesday morning December 13/14 when in excess of 60 shower members can be seen each hour from rural observing sites. The radiant is located at 07:28 (112) +32. This position lies in northern Gemini near the fourth magnitude star Rho Geminorum. This shower should be very activie this weekend with hourly rates near midnight ranging from 10 Friday night/Saturday morning to 25 Saturday night/Sunday morning. Although Geminid meteors can be seen all night long, they are best seen near 0200 LST when the radiant lies highest above the horizon. 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. This is one of the few displays that can be well seen prior to midnight. Unfortunately the first quarter moon will reduce rates until it approaches the western hornizon near midnight.

Puppid-Velids (PUP)

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. The center of this activity is currently located at 08:08 (126) -45. This position lies in western Vela, five degrees northeast of the second magnitude star Gamma Velorum. Peak rates occurred near December 7 so current activity is waning 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. At 40 km/sec. the Puppid-Velids produce meteors of average velocity.

Sigma Hydrids (HYD)

The Sigma Hydrids (HYD) are active from November 26 through December 20. Maximum activity occurred on December 6. The radiant is currently located at 08:16 (129) +02. This position lies in western Hydra, just below 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. Current rates would be ~1 per hour no matter your location. At 61 km/sec. the Sigma Hydrids produce mostly swift meteors.

December Leonis Minorids (DLM)

The December Leonis Minorids (DLM) are active from a radiant located at 10:22 (155) +34. This position lies in central Leo Minor, approximately ten degrees north 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 ~1 per hour as seen from the northern hemisphere and < 1 per hour as seen from south of the equator. At 64 km/sec. the December Leonis Minorids produce mostly swift meteors.

Coma Berenicids (COM)

Activity from the Coma Berenicids (COM) has just begun for 2010. The radiant is located at 11:30 (172) +19. This position actually lies in eastern Leo, six degrees northwest 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 peaks on December 16th so current rates would be ~2 per hour as seen from the northern hemisphere and ~1 per hour as seen from south of the equator. At 65 km/sec. the Coma Berenicids produce mostly swift meteors.

Psi Ursa Majorids (PSU)

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. The radiant is currently located at 11:55 (179) +41. 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. With the shower ending this weekend, current rates would most likely be < 1 per hour. At 61km/sec., the average Psi Ursa Majorid meteor would be swift.

December Alpha Draconids (DAD)

Lastly, the December Alpha Draconids (DAD) are active from a radiant located at 14:00 (210) +58. This position actually lies in northeastern Ursa Major, six 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 < 1 no matter your location. At 44 km/sec. the Alpha Draconids produce mostly medium speed meteors.

Shower Name                 RA     DEC   Vel     Rates
                                         km/s   NH    SH
ANT Antihelions           06h 12m  +23    30     3     2
MON Monocerotids          06h 48m  +08    41     1     1
GEM Geminids              07h 28m  +32    35    25     5
PUP Puppid-Velids         08h 08m  -45    40    <1     2
HYD Sigma Hydrids         08h 16m  +02    61     1     1
DLM Dec Leonis Minorids   10h 22m  +34    71     1    <1
COM Coma Berenicids       11h 30m  +19    65     2    <1
PSU Psi Ursa Majorids     11h 55m  +41    61    <1    <1
DAD Dec Alpha Draconids   14h 00m  +58    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

Geminids – 2nd Session Results

My second session of the night saw an increase in rates from a few hours ago. Between 4:57 am (11:57 UT) and 5:49 am (12:49 UT), I counted 30 meteors of which 22 were Geminids. The sky was significantly darker than a few hours earlier with a limiting magnitude of +5.7. A quick calculation gives a ZHR of ~81 which is an improvement over the ZHR of ~68 I measured before.

Tomorrow morning should see a 50-100% increase in rates compared to tonight.

I’ll have the video results posted sometime during the day.

Geminids – First Session Results

I was able to spend ~40 minutes watching the Geminids so far tonight. This first session lasted from 11:43 pm (6:43 UT) till 12:28 am (7:28 UT). With a limiting magnitude of +5.4, I counted 23 meteors with 13 being Geminids and 10 being non-Geminids (I wasn’t keeping track of any of the other showers so these go in the log as Sporadics). Based on a total observing time of ~0.7 hours, limiting magnitude of +5.4, field correction of 1.11, r population index of 2.6, radiant elevation of 60° and number of Geminids seen of 13, my quick ZHR calculation gives a ZHR of ~68. That’s about half of what the rate should be tomorrow morning.

If the weather holds out (there is some cirrus around) and my little newborns let me I’ll try to get in another session or two tonight.

Dec 11/12 Meteors

Today we welcome a new camera to the Transient Sky family. Salvador Aguirre is operating his MetRec-run PARENI system down in Hermosillo in the Mexican state of Sonora. Hermosillo is 217 miles to the south of Tucson. Though the cities are relatively close PARENI and SALSA3 will not be seeing the same meteors. That is not the case with our all-sky Sentinel cameras and in fact we both recorded a mutual fireball back on Nov 29 UT. Salvador and I have been working hard for the past year to get his system up and running. Though he’s no stranger to this blog, let’s all welcome him and PARENI!

Check out Salvador’s blog for images of the Geminids from his all-sky camera.

The Geminids saw a significant bump up in activity last night with 22 detections (up from 8 and 5 the past two nights). Tonight should see that number more than double. Though Tuesday morning is maximum, Monday morning will see good rates and it would be worth it for visual observers to watch then as well.

Last night also marked SALSA3′s 78th consecutive night with a meteor detection.

Obs  Date(UT)      Time    TOT SPO ANT GEM HYD PSU PUP DAD DLM MON COM
SAL3 2010-12-12   11h 18m   45  11  2   22  3   1   0   0   0   2   4
ALLS 2010-12-12   11h 34m   22  6   1   8   4   0   0   1   1   1   0
HERM 2010-12-12   10h 34m   29  15  3   7   1   -   2   -   -   -   1

SAL3 - SALSA3 camera in Tucson (Carl Hergenrother)
ALLS - Near all-sky camera in Tucson (Carl Hergenrother)
VIST - Visual observations from Tucson (Carl Hergenrother)
HERM - PARENI camera in Hermosillo (Salvador Aguirre)
SDG - Camera in San Diego operated by Bob Lunsford
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   
GEM - Geminids
HYD - Sigma Hydrids
PSU - Psi Ursa Majorids
PUP - Puppids-Vellids
DAD - December Alpha Draconids
DLM - December Leonis Minorids
MON - Monocerotids
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