Meteor Activity Outlook for December 29-January 4, 2013

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.

During this period the moon wanes from its current full phase to a little more than one-half illuminated on January 4, 2013.  This weekend the waning gibbous moon will rise during the early evening hours and will effectively ruin the sky with intense moonlight the remainder of the night. As the week progresses the moon will rise a little later each evening but the more active morning hours will still be compromised by moonlight. The strong Quadrantid meteor shower will peak on Thursday morning January 3rd, with a bright gibbous moon located near the Leo-Virgo border. Activity can be still seen from the Quadrantids if your skies are clear and transparent. It would also be wise to keep the moon out of your field of view by facing the north to east quadrant of the sky. The estimated total hourly meteor rates for evening observers this week is near two for observers located at mid-northern latitudes and one for observers in mid-southern latitudes. For morning observers the estimated total hourly rates should be near five from the mid-northern hemisphere and three 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 this entire period due to intense 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 29/30. These positions do not change greatly day to day so the listed coordinates may be used during this entire period.

The table below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning . Details of each shower will again be provided next week when the situation with moonlight improves.

Antihelions (ANT) – 07:24 (111) +21   Velocity – 30km/sec.
Northern Hemisphere – 1 per hr.   Southern Hemisphere – <1 per hr

Alpha Hydrids (AHY) – 08:12 (123) -07   Velocity – 45km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

January Leonids (JLE) – 09:48 (147) +25   Velocity – 45km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

December Leonis Minorids (DLM) – 11:20 (170) +26   Velocity – 64km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

Coma Berenicids (COM) – 12:20 (185) +13   Velocity – 69km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

Dec. Sigma Virginids (DSV) – 14:16 (214) +02    Velocity – 44km/sec.
Northern Hemisphere – <1 per hr.   Southern Hemisphere – <1 per hr

Quadrantids (QUA) – 15:24 (231) +49   Velocity – 42km/sec.
Northern Hemisphere – <1 per hr. Southern Hemisphere – <1 per hr

Clear Skies!
Robert Lunsford
American Meteor Society

Moon and Jupiter Put On a Christmas Show

Christmas evening conjunction as seen from Tucson at 7:00 pm. Created with Stellarium.

Christmas evening conjunction as seen from Tucson at 7:00 pm. Created with Stellarium.

This Christmas evening the Moon and Jupiter will make a beautiful pair. The image to the right shows what the two will look like from Tucson around 7 pm local time. The Moon is not quite full as Full Moon isn’t till Dec 28.

As close as the two get from each other for northern observers, the Moon will actually pass in front of, or occult, Jupiter for skywatchers from central South America to southern Africa. A map and list of times can be found at the International Occultation Timing Association.

On Christmas eve, the Moon will be located near the Pleiades which is the small “little dipper”-looking star clusters near the top of the image to the right.

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

2012 Geminids Recap

The 2012 Geminid meteor shower is now over. Dark Moon-less skies allowed for observers to get many hours of prime Geminid observing in. Here in southern Arizona the weather produced a different sort of showers on the night of the maximum as rain fell for the first time in a month. Luckily it was clear the night before maximum and rates were surprisingly strong.

The International Meteor Organization hosts a Live ZHR page that tabulated visual meteor observations from observers from all over the world and updates the shower’s activity profile in real-time. As of Dec 22, 133 observers in 36 countries reported 18,000 meteors.

Peak activity was predicted for 23:30 hours UT on December 13 making the peak effectively 0 hours UT on the 14th. From the ZHR profile below, the best rates did occur within a few hours of the predicted peak. At that time the ZHR reached ~120 meteors per hour. Even under less than perfect skies, a fine show was guaranteed.

gem2012overview

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The IMO Live ZHR page also presents a map of the location of all 133 observers. I always find it interesting to see the distribution of meteor observers around the world. The radiant of the Geminids is located at a declination of +33° making this shower easier to see from the Northern Hemisphere. Though still visible from the latitudes of Australia, New Zealand and the middle of South America, the shower would be low on the northern horizon and rates would be much less than seen up north. Still a fair number of Southern Hemisphere observers reported meteors. It is nice to see many more observations coming in from across Asia especially in countries like Iran, India, Nepal and Thailand.

world_small

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Latest on Comet Pons-Gambart

I last reported on newly (re)-discovered comet C/2012 V4 back on December 8. Though comet C/2012 V4 has been linked with Comet Pons-Gambart which was last seen in 1827, it still has not been officially named Pons-Gambart.

Earthbound observers estimated it at magnitude 8.5 to 9.5 during the first half of December. Unfortunately the comet is now too close to the Sun to be seen from Earth. It won’t be seen again till sometime in mid to late January. How bright it’ll be at that time is debatable. There has been some talk on the comets-ml list that the comet continued to brighten after perihelion in 1827. If true and if the comet behaves the same way, the comet may still be bright enough at the end of January for small telescope observers.

As mentioned in my December 8 posting, one of the STEREO sun watching spacecraft has not only had a clear view of the comet but the comet passed within ~0.28 AU of the spacecraft on December 12. The movie below shows the comet rapidly brightening and displaying a lengthening tail as the comet zips past STEREO-B and off its camera FOV. Note that the tail on the last few frames almost extends from one edge of the field to the other. It is a clear reminder of how our view of a comet (faint and not much to get excited about from Earth while a naked eye object with a 20+ deg long tail from STEREO-B) is dependent on our viewing conditions.

C2012V2_STEREO_20121211

Lunar Occultation is Actually Tonight

Big mistake on my part… The lunar occultation I mentioned in the last post is actually occurring tonight (as in Sunday night) and not Monday as I mentioned.

Sorry for the mix-up.

Lunar Occultation of Star Monday Evening

As the Moon travels across the sky it passes in front of many stars. Most of the time these stars are too faint to be easily seen near a bright Moon. On occasion the Moon will pass in front of bright stars or even the planets in an event that can be followed with the naked eye. This Monday evening the Moon will pass in front of the 4th magnitude star ν (nu) Aquarii.

Moon_nuAqr

The occultation will be visible from the central and western states of the United States, as well as northern Mexico and south central and southwestern Canada (see the map below). Though Hawaii is in the path it will be daylight at the time of the time of the occultation. For observers in the eastern US they will only see the Moon approach the star but not pass in front of it before the Moon sets. The image to the right shows the Moon and ν (nu) Aquarii at ~9:10 pm MST from Tucson, Arizona. This is right before the time of disappearance. To get times for the disappearance and reappearance of the star behind the Moon from many different locations, go to the International Occultation Timing Association’s (IOTA) page for this occultation.

 

Map of the path of the occultation. Credit: IOTA.

Map of the path of the occultation of nu Aqr. Credit: International Occultation Timing Association (IOTA).

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

Geminids Peak

The Geminids meteor shower was forecast to reach its peak last night (Dec. 13/14, Thu/Fri night). According to reports submitted to the International Meteor Organization, Zenithal Hourly Rates (ZHR) may have reached as high as 140-150 per hour around midnight last night Tucson time. This high peak seems to have been rather sharp and other observers recorded ZHRs in the 60-100 range.

ZHR rates for the 2012 Geminids from the IMO's Live ZHR page. Credit: International Meteor Organization.

ZHR rates for the 2012 Geminids from the IMO’s Live ZHR page. Credit: International Meteor Organization.

Here in Tucson we had a different kind of shower as it rained for the first time in a month. With ~0.58″ of rain last night it was the wettest event since late August. Luckily it does appear that Geminid rates on Wed/Thu night were almost, if not, as good as rates during the peak night. The Geminid rates routinely fall off rapidly after the peak so though some Geminids should be visible tonight rates may be much lower than the past two nights.

Salvador Aguirre operates an allsky fireball camera in Hermosilla, Sonora. The youtube video below is his compilation of meteors from Wed/Thu night. More can be seen on his blog.

Great Geminids Display Last Night

The Geminids aren’t expected to peak till tonight and yet last night they were definitely alive and kicking. In fact, I would rank last night’s display as one of the better (non-Leonid outburst) showers that I have ever seen. Makes me wonder if tonight will be even better or are the Geminids peaking early.

Tonight it is supposed to rain here in Tucson so I decided to make last night my dedicated Geminid watch night. Within about 2-3 minutes of stepping outside I had already seen 4 Geminids. Things were looking good. Between 8:08 and 10:26 UT (1:08 and 3:26 am local time) I counted 154 Geminids and 24 sporadics (really non-Geminids since I wasn’t keeping track of any of the other active showers) under a sky with a limiting magnitude of +6.1. The Geminids came in bunches. There were multiple occurrences of 3-4 Geminids visible within a span of 10-30 seconds. At the other extreme there were a few dry spells when no meteors were seen for about 4 minutes. The brightness of the Geminids also seemed to be patchy with 10-20 minutes of bright 0th to 2nd magnitude meteors followed by 10-20 minutes of only 3rd magnitude or fainter ones.

The best meteor of the night was not a Geminid but a nice -4 magnitude sporadic that flared a few times right in the middle of my view. Its motion was consistent with being a Sigma Hydrid, one of the lesser showers active last night.

The IMO’s Live ZHR graph showed the Geminids reaching a ZHR rate of ~110 meteor per hour last night.

The weather is expected to be bad for Tucson tonight so I doubt I’ll be able to watch. But for those of you under clear skies, the Geminids will surely put on a nice show. The best time to watch is between 10 pm and dawn. Though the meteors appear to radiate from the constellation of Gemini (from the northeast between 10 pm and midnight, overhead between midnight and 4am and from the northwest from 4am till dawn) the meteors can be seen anywhere in the sky. Where you look isn’t as important as finding a comfortable position (reclining chairs are the best) with an unobstructed view free from lights, buildings and trees. Also remember it is cold out there and meteor watching involves lots of sitting still so dress even warmer than you would otherwise.

Happy viewing!

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