Meteor Activity Outlook for February 26-March 4, 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.

March is the slowest month for meteor activity. No major annual showers are active and only two very weak minor showers produce activity this month. The sporadic rates continue a slow decline as seen from the mid-northern latitudes and mid-southern rates reach a first half minimum. There is not much to look forward to this month expect for the evening fireballs that seem to peak this time of year from the northern hemisphere. This could be due to the fact the antiapex radiant lies highest above the horizon this time of year during the evening hours.

During this period the moon reaches its new phase on Friday March 4th. At that time the moon lies near the sun and cannot be seen at night. This weekend the waning crescent moon will rise during the early morning hours and will cause a problem if one observes with the moon in your field of view. To see the most activity simply view in a direction that places the bright moon out of your field of view. The estimated total hourly rates for evening observers this week is near three as seen from the northern hemisphere and four as seen from the southern hemisphere. For morning observers the estimated total hourly rates should be near seven from the northern hemisphere and ten as seen from south of the equator. 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 for the morning hours due to the bright 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 February 26/27. 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)

The wide Antihelion (ANT) radiant is now centered at 11:24 (171) +02. This area of the sky lies in eastern Leo, three degrees south of the fourth magnitude star Sigma Leonis. This radiant is best placed near 0100 local standard time (LST) when it lies on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from eastern Leo, Sextans, Crater, or western Virgo could be a candidate for this shower. Rates at this time should be near two per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

Gamma Normids (GNO)

The Gamma Normids (GNO) is a weak shower best seen from the southern hemisphere. This shower is only visible south of forty degrees north latitude. The further one is located south (down to 50S) the better the radiant is situated in the sky. Expected rates from the southern hemisphere is currently less than one per hour, even with the radiant located high in the sky. The current radiant position lies at 15:36 (234) -53. This position lies in western Norma, five degrees east of the third magnitude star Zeta Lupi. The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon in a dark sky. At 56km/sec. the Gamma Normids would produce mostly swift meteors.

As seen from the mid-northern hemisphere (45N) one would expect to see approximately five 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 eight per hour as seen from rural observing sites and three per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Morning rates are slightly reduced due to moonlight.

The list below presents a 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           11h 24m  +02    30     2     2
GNO Gamma Normids         15h 36m  -53    56    <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

Feb 14/15 to 22/23 Meteors

It’s been an amazing run the past few months. From the end of September until the very last day of 2010, the nights in Tucson were clear enough to allow a few meteors to be detected. Even January was clear 30 out of 31 nights. February started off just as clear but last week the clouds finally won out with 4 whole nights being lost to bad weather. It wouldn’t have been so bad if the clouds had actually brought more than a measly 0.05″ of rain. Perhaps we’ll do better with the storm forecast to hit this weekend.

Bob’s notes …

Feb 21/22: “The sky was clear at dusk but clouds quickly formed during the early evening hours, covering the entire sky by 2200 (10pm). No meteor activity was recorded after this time.”

Feb 20/21: “We lost 5 nights due to recent storms that affected both San Diego and Tucson. This night had lots of post-frontal cirrus and a bright moon, which accounted for the low counts.”

Feb 14/15: “The forecast was for cloudy skies but the sky was clear the entire night. Despite the bright moon that was above the horizon most of the night, a decent total of 22 meteors were recorded. The constellation of Leo was once again the center of attention with 3 Antihelion and several sporadic meteors. Our weather forecast calls for clouds and rain for the next week. It has been a nice run of 15 nights in a row with observations. Not bad for this area in February! Hopefully we can return to better weather later in the month and on into March.”

Obs  Date(UT)      Time    TOT SPO ANT BHE DLE
SAL3 2011-02-23   11h 04m   12  12  0   -   0
ALLS 2011-02-23   11h 24m   8   8   0   -   0

SAL3 2011-02-22   11h 06m   13  13  0   -   0
ALLS 2011-02-22   11h 34m   9   8   0   -   1
SDG  2011-02-22   10h 16m   3   2   1   -   -

SAL3 2011-02-21   00h 00m     BAD WEATHER!
ALLS 2011-02-21   00h 00m     BAD WEATHER!
SDG  2011-02-21   08h 01m   13  11  2   -   -

SAL3 2011-02-20   00h 00m     BAD WEATHER!
ALLS 2011-02-20   00h 00m     BAD WEATHER!

SAL3 2011-02-19   00h 00m     BAD WEATHER!
ALLS 2011-02-19   00h 00m     BAD WEATHER!

SAL3 2011-02-18   11h 13m   7   6   0   -   1
ALLS 2011-02-18   11h 41m   6   5   1   -   0

SAL3 2011-02-17   00h 00m     BAD WEATHER!
ALLS 2011-02-17   00h 00m     BAD WEATHER!

SAL3 2011-02-16   11h 17m   11  9   2   0   0
ALLS 2011-02-16   11h 45m   6   6   0   0   0

SAL3 2011-02-15   11h 18m   14  13  0   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   
BHE - Beta Herculids
DLE - Delta Leonids

Feb 10/11 to 13/14 Meteors

The Moon is approaching Full so nightly rates should drop. This may all be moot as a series of storms are forecast to affect the area starting Wednesday and continuing into next week. Now the question is will we actually get a good soaking or will these storms just bring clouds.

Obs  Date(UT)      Time    TOT SPO ANT BHE
SAL3 2011-02-14   04h 56m   10  10  0   0
ALLS 2011-02-14   11h 32m   9   7   0   2

SAL3 2011-02-13   11h 22m   19  16  3   0
ALLS 2011-02-13   11h 50m   9   8   1   0
HERM 2011-02-13   09h 19m   12  11  1   0

SAL3 2011-02-12   11h 23m   15  13  1   1
ALLS 2011-02-12   11h 38m   5   4   0   1

SAL3 2011-02-11   11h 25m   10  9   0   1   
ALLS 2011-02-11   11h 54m   4   4   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   
BHE - Beta Herculids

Feb 5/6 to 9/10 Meteors

The usual low February rates continue. Well with the exception of the night of Feb 6/7 when SALSA3 caught twice as many meteors relative to the other nights. I should probably take another look at that data to make sure everything’s valid.

Below is Bob’s excellent nightly commentary to go with his observations:::

Jan 31/Feb 1 – “I lost two nights due to clouds and rain. The day of February 1st was partly cloudy but the sky had totally cleared by sunset. Unfortunately there were clouds off the coast which arrived after sunset preventing me from recording any activity prior to 10:20 PST. It remained clear until 00:20 when another patch of clouds obscured the sky. This lasted until 01:30, when it finally cleared for the remainder of the night. Although it was clear during the time the ACE radiant was above the horizon, no activity from that radiant was recorded this morning. Totals from the other sources of activity were compromised due to clouds.”

Feb 5/6 – “The weather conditions continue to deteriorate as a front passes to the north. The evening hours had patches of low clouds interfering with observations, especially between 6-8UT (10pm-12am PST). After 10UT (2am PST) the sky became completely overcast and observations were stopped. Only five meteors were recorded, nothing noteworthy.”

Feb 6/7 – “Contrary to the weather forecast, the sky remained clear the entire night. Despite the favorable conditions, meteor totals were unimpressive. We have lost the Alpha Centaurids from this site as the radiant does not now clear the southern horizon.”

Feb 7/8 – “Clouds were a problem tonight. The the sky was clear from dusk to 2000 (8pm PST). After 2000, clouds interfered with observing until 2300 (11pm PST), when skies cleared again. It remained clear until 0130, when it became totally overcast and remained that way the remainder of the night. Of the 14 meteors recorded, only one was associated with a shower (Antihelion). Plots did not reveal any other possible radiants.”

Obs  Date(UT)      Time    TOT SPO ANT ACE PIH
SAL3 2011-02-10   11h 27m   11  11  0   -   -
ALLS 2011-02-10   10h 42m   3   3   0   -   -

SAL3 2011-02-09   11h 28m   12  12  0   -   -
ALLS 2011-02-09   11h 57m   5   5   0   -   -
HERM 2011-02-09   09h 55m   8   7   1   -   -

SAL3 2011-02-08   11h 30m   12  10  2   -   0
ALLS 2011-02-08   11h 59m   6   6   0   -   0
SDG  2011-02-08   06h 38m   14  13  1   -   0
HERM 2011-02-08   08h 20m   13  12  0   -   1

SAL3 2011-02-07   11h 31m   8   7   1   -   0
ALLS 2011-02-07   11h 52m   9   8   0   -   1
SDG  2011-02-07   09h 53m   26  22  4   -   0
HERM 2011-02-07   11h 05m   6   6   0   -   0

SAL3 2011-02-06   11h 33m   14  13  1   0   0
ALLS 2011-02-06   12h 02m   8   7   1   0   0
SDG  2011-02-06   07h 37m   5   4   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   
ACE - Alpha Centaurids
PIH - Pi Hydrids

Meteor Activity Outlook for February 12-18, 2011

February offers the meteor observer in the northern hemisphere a couple of weak showers plus falling sporadic rates. This may not seem too exiting but you never know when surprises are in store. An errant earthgrazer from the Centaurid complex may shoot northward. Better yet, a bright fireball may light up the sky. February is the start of the fireball season, when an abundance of fireballs seem to occur. This lasts well into April and seems to occur mostly during the early evening hours.

Observers in the southern hemisphere are treated to the Alpha Centaurid peak on the 8th plus the entire Centaurid complex of radiants is active all month long. Sporadic rates are slightly less than those seen in January, but still stronger than those witnessed north of the equator.

During this period the moon reaches its full phase on Friday February 18th. At that time the moon lies opposite the sun in the sky and is in the sky all night long. This weekend the waxing gibbous moon will set during the early morning hours, allowing a few hours of dark sky before the onset of morning twilight. This window of opportunity shrinks with each passing night until it is essentially zero on Thursday February 17th. The estimated total hourly rates for evening observers this week is near two 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 thirteen from the northern hemisphere and twenty as seen from south of the equator. 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 February 12/13. 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)

The wide Antihelion (ANT) radiant is now centered at 10:28 (157) +08. This area of the sky lies in southern Leo, two degrees west of the fourth magnitude star Rho Leonis. This radiant is best placed near 0100 local standard time (LST) when it lies on the meridian and is located highest in the sky. Due to the large size of this radiant, any meteor radiating from northwestern Hydra, Sextans, Leo, western Virgo, or eastern Cancer could be a candidate for this shower. Rates at this time should be near two per hour no matter your location. With an entry velocity of 30 km/sec., the average Antihelion meteor would be of medium-slow speed.

Alpha Centaurids (ACE)

The Alpha Centaurids (ACE) are active from a radiant located at 14:24 (216) -61. This position lies in southeastern Centaurus, directly between the brilliant first magnitude star Hadar (Beta Centauri) and Rigel Kentaurus (Alpha Centauri). The radiant is best placed during the last dark hour before dawn, when it lies highest above the horizon. At this position, these meteors are only visible south of 30 degrees north latitude. The further one is located south (down to 60S) the better the radiant is situated in the sky. Current rates from the southern hemisphere should be between 3-5 per hour. At 56km/sec. the Alpha Centaurids would produce mostly swift meteors.

Beta Herculids (BHE)

Studies by Sirko Molau and Juergen Rendtel of the IMO’s video data base of nearly a half million meteors has revealed a weak radiant active in Hercules this time of year. The Beta Herculids (BHE) is a shower of short duration with an activity period from February 10-14. Maximum activity occurs on February 13th. The radiant position for the morning of February 13th would be 16:24 (246) +24. This position lies in western Hercules, three degrees north of the third magnitude star Kornephoros (Beta Herculis). These meteors are best seen near 0500 LST when the radiant lies highest above the horizon in a dark sky. Rates are most likely less than one shower member per hour, no matter your location. At 56km/sec. the Beta Herculids would produce mostly swift 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 one per hour. As seen from the mid-southern hemisphere (45S), morning rates would be near fourteen per hour as seen from rural observing sites and two per hour during the evening hours. Locations between these two extremes would see activity between the listed figures. Evening rates are reduced due to 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           10h 28m  +08    30     2     2
ACE Alpha Centaurids      14h 24m  -61    56    <1     4
BHE Beta Herculids        16h 24m  +24    56    <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

Jan 31/1 to Feb 4/5 Meteors

The past week has seen a usual amount of meteor activity, well at least for early February. The last 2 days of January saw a mix of rain and clouds as the soon-to-be much stronger Groundhog Day Blizzard of 2011 moved through the US southwest. Though we only got 0.12″ of rain at my house (which all fell while I was at lunch), the storm did usher in a record-breaking cold for Tucson. Though back-to-back low temperatures of 19F and 18F may not be out of the norm for most people, here in Tucson that’s cold. As a result, I decided not to turn on my allsky cam those nights since I didn’t want its internal heater running full blast all night (I was actually thinking of the damage to my electricity bill more than any damage to the camera). SALSA3 was left on and worked fine.

This post includes the 1st time I can present meteor data from all 3 MetRec sites in this part of the world. On the night of Jan 31/Feb 1, my Tucson based camera as well as Bob Lunsford’s San Diego based camera and Salvador Aguirre’s Hermosillo based camera all reported data. Hopefully this will be the first of many nights with coverage from the tri-camera area.

As always, Bob has provided excellent nightly commentary to go with his observations:::

Jan 31/Feb 1 – “I lost two nights due to clouds and rain. The day of February 1st was partly cloudy but the sky had totally cleared by sunset. Unfortunately there were clouds off the coast which arrived after sunset preventing me from recording any activity prior to 10:20 PST. It remained clear until 00:20 when another patch of clouds obscured the sky. This lasted until 01:30, when it finally cleared for the remainder of the night. Although it was clear during the time the ACE radiant was above the horizon, no activity from that radiant was recorded this morning. Totals from the other sources of activity were compromised due to clouds.”

Feb 1/2 – “It was clear the entire night. Activity was near normal for this date and conditions. Shower activity was slightly lower than expected. Unfortunately no Alpha Centaurids were recorded, which is my prime target this time of year.”

Feb 2/3 – “This was a rather forgettable session. First of all, I fell asleep before dusk and did not wake until just before 10pm PST (0600 UT). When checking the results for February 3rd the following evening, I was baffled as to why no activity was recorded after 2:40 PST (10:40 UT). When I started the camera for the next night’s session, it became clear. There was no power to the camera. A quick inspection revealed the cause. Some varmint had chewed the power cord in half on the morning of the 3rd. There were bite marks on the cord where it was closest to the ground. Thus I had lost three hours of clear sky plus another opportunity to try to record more ACE activity. Luckily I had a spare cord available and after a short delay, the session for February 4th was started. But that is another story…”

Feb 3/4 – “The sky was clear the entire night. Meteor totals were slightly better than expected. Shower activity was nearly totally absent though. Plots reveal a tight radiant near 10:30 (157) -12 that produced five meteors. This position lies on the Hydra/Sextans border.”

Obs  Date(UT)      Time    TOT SPO ANT DLM ACE PIH
SAL3 2011-02-05   11h 34m   16  14  1   -   0   1
ALLS 2011-02-05   11h 46m   10  9   1   -   0   0

SAL3 2011-02-04   11h 28m   21  20  0   0   0   1
SDG  2011-02-04   10h 49m   38  36  1   1   0   0

SAL3 2011-02-03   11h 37m   18  15  1   1   1   -
SDG  2011-02-03   04h 40m   13  10  3   0   0   -

SAL3 2011-02-02   11h 32m   16  15  1   0   0   -
ALLS 2011-02-02   11h 46m   3   3   0   0   0   -
SDG  2011-02-02   11h 31m   31  28  2   1   0   -

SAL3 2011-02-01   04h 47m   13  12  1   0   0   -
ALLS 2011-02-01   11h 51m   12  9   2   1   0   -
SDG  2011-02-01   11h 26m   23  20  2   1   0   -
HERM 2011-02-01   10h 58m   8   7   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   
HYD - Sigma Hydrids
DLM - December Leonis Minorids
ACE - Alpha Centaurids
PIH - Pi Hydrids

Jan 21/22 to 30/31 Meteors

After some downtime due to computer issues and bad weather, Bob’s cameras are once again capturing meteors. Bob’s nightly summary give a great synopsis of meteor activity during the last week of January so I’ll let him do the talking…

Jan 21/22 – “After a long delay due to cloudy weather and computer problems, I am back in business with a new computer and hopefully some clear skies. This session was good despite the bright waning gibbous moon. The December Leonis Minorids were well represented but the Gamma Ursid Minorids did not produce any activity.”

Jan 24/25 – “The sky was clear the entire night. I had somewhat of a late start as I was busy at sunset plus I had to tweak some settings on my new computer to get it to work properly. Meteor totals are close to what is to be expected for this setup in late January.”

Jan 25/26 – “The sky was clear the entire night. I still started about 30 minutes late due to computer problems. Meteor totals for the night are near normal but the individual shower totals are high. The 27 sporadics are low for an entire night for this setup. The ANT’s and the DLM’s produced 6 and 4 meteors respectively, which is higher than normal this time of year.”

Jan 26/27 – “The sky was clear the entire night. It was another good night for shower activity with 6 Antihelion and 3 December Leonis Minorids being recorded.”

Jan 27/28 – “The sky was clear the entire night. Activity was less than the previous few nights. Surprisingly 3 Alpha Centaurids were recorded on the first night of their activity period.”

Jan 28/29 – “This was the last of a nice clear stretch observed in extreme southwestern CA. The sky was clear all night long. A waning crescent moon rose late in the session but did not compromise observations. Rates were good with 41 meteors being recorded. The Alpha Centaurids continue to be strong with 4 members being recorded during the last few hours of the night. No December Leonis Minorids were recorded.”

Obs  Date(UT)      Time    TOT SPO ANT DLM ACE
SAL3 2011-01-31   00h 00m   0   0   0   0   0
ALLS 2011-01-31   00h 00m   0   0   0   0   0

SAL3 2011-01-30   11h 43m   10  8   2   0   0
ALLS 2011-01-30   12h 12m   5   4   0   1   0

SAL3 2011-01-29   11h 44m   14  11  1   1   1
ALLS 2011-01-29   12h 14m   10  8   0   1   1
SDG  2011-01-29   11h 28m   41  34  3   0   4

SAL3 2011-01-28   11h 40m   15  13  0   1   1
ALLS 2011-01-28   11h 55m   10  10  0   0   0
SDG  2011-01-28   11h 17m   37  28  5   1   3

SAL3 2011-01-27   11h 41m   17  15  2   1   -
ALLS 2011-01-27   11h 55m   12  10  2   1   -
SDG  2011-01-27   10h 58m   52  43  6   3   -

SAL3 2011-01-26   09h 31m   18  17  1   0   -
ALLS 2011-01-26   12h 18m   12  10  2   0   -
SDG  2011-01-26   10h 37m   37  27  6   4   -

SAL3 2011-01-25   11h 50m   14  11  1   2   -
ALLS 2011-01-25   12h 18m   8   7   1   0   -
SDG  2011-01-25   08h 30m   40  36  2   2   -

SAL3 2011-01-24   11h 51m   12  9   2   1   -
ALLS 2011-01-24   12h 19m   4   4   0   0   -

SAL3 2011-01-23   11h 52m   20  18  1   1   -
ALLS 2011-01-23   12h 21m   8   7   1   0   -
                                            
SDG  2011-01-22   10h 51m   34  28  2   4   -  GUM=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   
HYD - Sigma Hydrids
DLM - December Leonis Minorids
ACE - Alpha Centaurids
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