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In the Sky This Month – November 2009 November 7, 2009

Posted by Carl Hergenrother in Asteroids, Comets, Meteors, planets.
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This feature highlights a number of meteor showers, comets and asteroids which are visible during the month of November 2009. Jupiter continues its reign as not only king of the planets but king of the evening sky. November also brings the Leonids which may put on a good show for some observers this year.

Note: If anyone has pictures or observations of these objects/events and want to share them, send me a comment and I’ll post them on the blog.

Planets

Jupiter - Jupiter continues to dominate the evening sky. At magnitude -2.4, Jupiter is ~10 times brighter than the brightest stars in the sky this month. Of all the planets, only Venus, and on very rare occasions Mars, are brighter.

Jupiter is located high in the southern sky by the end of dusk for easy observation. As has been the case all year, it is slowly moving through the southern constellation of Capricornus.

Nov 23 - Moon passes 3° from Jupiter

Neptune – For those with a telescope or binoculars and a dark sky, Neptune is located within 1/2 to 3/4 degrees of Jupiter. Jupiter will be a bright magnitude -2.4 while Neptune will be a faint +7.9. Even Jupiter’s 4 large Galilean moons are about a dozen times brighter than Neptune even though they are much smaller. The big reason for the faintness of Neptune is its distance from both the Earth and Sun. It is roughly 6 times further away from us and the Sun as Jupiter. The distance also explains its apparent small size of 2.3″. A good sized telescope will be required to see Neptune as anything other than a faint star.

Uranus – Uranus is located in western Pisces and is bright enough to be seen in small binoculars at magnitude +5.8 but will still require a telescope in order to see it as anything other than a star (it’s disk is only 3.5″ across).

Mars – Mars can be seen rising in the eastern sky late in the evening (~11 pm at the start of the month and ~9 pm at the end of the month). Mars is rapidly brightening and will reach magnitude 0.0 by the end of the month, matching that of many of the brightest stars visible in the morning sky. Mars will continue to brighten as it approaches its opposition on Jan 29 of next year. This month Mars marches through eastern half of the constellation of Cancer.

Nov 9 – Moon passes close (3°) to Mars

Venus - Venus rises an hour before dawn. When it is visible it is easily the brightest “star” in the sky. It was at its highest in the morning sky back in August and is continuing its slow crawl lower. It is located just above the horizon in the ESE sky right before the start of dawn. For binocular and telescope users, Venus will appear nearly full and is much smaller than it appeared this spring (now 11″ across versus 50″ last spring).

Nov 15 – Moon passes 6° from Venus

Mercury - Mercury starts the month behind the Sun with superior conjunction occurring on November 5. For the rest of the month, Mercury slowly pulls away from the Sun into the evening sky. Southern hemisphere observers will be able to catch a glimpse of Mercury low in the WSW sky during evening twilight. Northern observers will have to wait till December for their chance at seeing Mercury again.

Nov 5 – Mercury at superior conjunction

Saturn – Saturn is easy to observe during the last few hours of the night. Located in Virgo at magnitude +1.0, Virgo only rises right before the start of dawn. Telescope users should note that Saturn’s rings are still close to edge-on.

Nov 12 – Moon and Saturn within 7° of each other

Meteors

November hosts the sometimes great Leonids. In addition, the background rate of meteors is near an annual high. The year is usually split in 2 with January through June having low rates with few major showers while July through December (really through the 1st week of January) have high rates with many major showers.

Sporadic Meteors

Sporadic meteors are not part of any known meteor shower. They represent the background flux of meteors. Except for the few days per year when a major shower is active, most meteors that are observed are Sporadics. This is especially true for meteors observed during the evening. During November, 12 or so Sporadic meteors can be observed per hour from a dark moonless sky.

Major Meteor Showers

Leonids (LEO)

The Leonids have produced some of the most spectacular meteor displays in history. Rates as high as ~70,000 meteors per hour (that’s ~20 meteors per second) were seen in 1833 and 1966. Every ~33 years, the parent comet of the Leonids, Comet Tempel-Tuttle, returns to the vicinity of the Earth. For a few years after Tempel-Tuttle’s last perihelion in 1998, the Leonids produced enhanced rates of meteors as high as 100s to 1000s of meteors per hour.

What will 2009 bring? In a normal year, the Leonids produce maximum rates of ~10-15 meteors per hour. This year there are a number of predictions of enhanced activity.

J. Vaubaillon presents his predictions for this year’s Leonids at the website of the L’Institut de Mécanique céleste et de calcul des éphémérides (IMCCE). The Earth will encounter 4 dense dust trails produced by the Leonid parent comet. On November 17 at ~21:43 UT (or half an hour to an hour later), the Earth will encounter a trail produced in 1466 which may produce as many as ~115 meteors per hour from a dark site. At nearly the same time, November 17 at 21:50 UT, the 1533 trail may produce 80 meteors per hour. Combined the 2 trails may (may being the important word) produce ~200 meteors per hour. A display this strong would not be considered a “storm” but would be better than the Perseids or Geminids at their best by nearly a factor of 2. The predicted times favor observers in central Asia. Unfortunately for those of us in the US, we will miss out.

Two weaker and much more uncertain trails will be observable from the Western hemisphere. On November 17 at ~7:27 UT, the 1567 trail may produce 25 meteors per hour. Since this is in addition to the usual background rate of Leonids may result in total rates of 35-50 per hour which is comparable to last month’s Orionids. Also on November 18 at ~3:29 UT, the very old 1102 trail may enhance activity by 10-50 meteors per hour.

What does this mean? Most of us, especially in the United States, will only see the “normal” maximum on the morning of November 17 with hopefully an extra dozen or two meteors per hour from the 1567 trail. For those located in central Asia, a very good shower may be visible. The Leonids are best observed in the hours before sunrise. They will appear to radiate from the western part of the constellation of Leo.

Minor Meteor Showers

Minor showers produce so few meteors that they are hard to notice above the background of regular meteors. Starting this month, info on most of the minor showers will be provided on a weekly basis by Robert Lunsford’s Meteor Activity Outlook.

Northern and Southern Taurids (NTA/STA)

The Taurids never produce more than ~5 meteors per hour. They make up for their low rates by being active for over two months and by producing many bright fireballs. Their fireballs are more apparent to the average observer because, unlike most meteor showers, the Taurids are observable all night long rather than just in the morning. There is a chance that the Taurids will produce a higher number of fireballs this year than usual. There is a good chance that most fireballs being reported this month will be Taurids. They are active for the entire month of November with the northern branch (NTA) peaking around November 14. Though named after the constellation of Taurus, theTaurids radiate from a point between the constellations of Taurus and Aries this month.

The Taurids are produced by Comet 2P/Encke. Encke is an enigmatic object with the shortest period for any known comet at 3.3 years. First observed in 1786, it has been observed over ~60 orbits and has been seen every year since 1993.

Additional information on these showers and other minor showers not included here can be found at the following sites: Robert Lunsford’s Meteor Activity Outlook, Wayne Hally’s and Mark Davis’s NAMN Notes, and the International Meteor Organization’s 2008 Meteor Shower Calendar.

Comets

Naked Eye Comets (V < 6.0)

None

Binocular Comets (V = 6.0 – 8.0)

None

Small Telescope Comets (V = 8.0 – 10.0)

Comet 88P/Howell

P/Howell is an evening comet and currently the brightest in the sky. Howell is a short-period comet and takes only 5.49 years to orbit the Sun. Ellen Howell was a student at Caltech when she found the comet on photographic plates taken on 1981 August 29 with the 48″ Palomar schmidt.

In 1981 the comet was on an orbit that never brought it closer to the Sun than 1.62 AU (perihelion distance). As a result, it never got very bright. A relatively close approach to Jupiter in 1990 changed its perihelion distance to 1.40 AU. Further perturbations by Jupiter have decreased its perihelion distance to 1.36 AU. The closer perihelion distance allows the comet to get bright enough for small backyard telescopes. In addition, the comet seems to be running about ~2 magnitude brighter than usual. No obvious reason for the additional brightening has been observed yet.

This year perihelion occurred on Oct 12 so the comet is currently moving away from the Sun and should be fading. A day after perihelion I observed the comet from Tucson with a 12″ dobsonian. The comet was very difficult to observe from the city. At the time, I estimated its brightness at magnitude 8.5. The comet should be a little fainter (from 8.8 to 9.5) this month. The comet is located low in the southwest sky after dusk and will spend most of the month in Sagittarius. At mid-month P/Howell will be 1.41 AU from the Sun and 1.79 AU from Earth.

A finder chart for Comet Howell can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet C/2006 W3 (Christensen)

This comet was discovered nearly 3 years ago on 2006 November 18 by Eric Christensen of the Catalina Sky Survey north of Tucson. At the time the comet was located 8.7 AU from the Sun which is nearly the distance of Saturn.

The comet reached perihelion at a rather distant 3.12 AU from the Sun on 2009 July 6. Because of its large perihelion distance, the comet will only slowly move away from the Sun and, though it will slowly fade, it should remain bright enough to be seen in modest sized backyard telescopes this month.

At mid-month, the comet is 3.37 AU from the Sun and 3.82 AU from Earth. Though observed as bright as magnitude ~8.2 it is now around magnitude 9.5 to 10.0. It is moving southeast while paralleling the summer Milky Way. This month the comet can be found in southern Aquila near the Sagittarius and is well placed for evening observing. This will probably be the last month that this comet will be observable in small scopes.

A finder chart for Comet Christensen can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet 217P/LINEAR

217P/LINEAR is also a short-period comet though it takes a little longer than Howell to circle the Sun, 7.83 years versus 5.49 years. P/LINEAR also comes closer to the Sun with perihelion at 1.22 AU from the Sun. The comet is already a month past perihelion which occurred on Sept 8.

P/LINEAR was first observed by the Lincoln Near Earth Asteroid Research (LINEAR) survey on 2001 June 21 though it wasn’t until 2001 July 11 that it was recognized as a comet. The 2009 apparition is the first return since the discovery apparition.

Though P/LINEAR and P/Howell have similar perihelion distances, LINEAR is a much fainter (or less active) comet. While Howell is ~9th magnitude at a rather distant 1.65 AU from Earth, P/LINEAR is a little fainter at magnitude ~10.0 though it is much closer (0.61 AU from Earth). This may be the last time to see P/LINEAR in small backyard telescopes until its 2048 return when it will pass within 0.40 AU of Earth. All the returns between 2009 and 2048 will be more distant.

I was able to observe 217P/LINEAR with 30×125 binoculars on the morning of Sept 25. In order to see the comet I had to drive out to a dark site. The comet was a rather nondescript smudge about 1.5′ across and with a brightness of magnitude 10.1. On Oct 16, I dragged my 12″ dob to a dark site. The comet was easy to observe with a nice short 0.08° long tail. At that time, the estimated brightness was magnitude 9.9.

This month the comet will be visible in the morning sky in the faint Milky Way constellation of Monoceros. It should remain at magnitude ~10 or a little fainter for the entire month. At mid-month the comet will be 1.49 AU from the Sun and 0.64 AU from Earth.

A finder chart for Comet LINEAR can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Comet C/2007 Q3 (Siding Spring)

This long-period was first seen on 2007 August 25 by Donna Barton of the Siding Spring Survey in Australia. This past Oct. 7th the comet reached a rather distant perihelion at 2.25 AU from the Sun. Unfortunately, the comet and Earth are located on opposite sides of the Sun so the comet is rather far from Earth. Still the comet is observable before the start of dawn as a ~9.0 to 9.5 magnitude comet near the Leo/Virgo border. At mid-month the comet is 2.30 AU from the Sun and 2.71 AU from Earth.

A finder chart for Comet Siding Spring can be found at Comet Chasing and Aktuelle Kometen (in German).

A nice collection of images can be found at the VdS-Fachgruppe Kometen (Comet Section of Germany) and Seiichi Yoshida’s Comet Homepage.

Asteroids

Binocular and Small Telescope Asteroids (V < 9.0)

(3) Juno

Juno was the 3rd asteroid to be discovered after (1) Ceres and (2) Pallas. It was found by German astronomer Karl Harding on September 1, 1804. With dimensions of 320×267×200 km (192 x 160 x 120 miles) Juno ranks as the 10th largest asteroid in the Main Belt though it is the 2nd largest stony S-type asteroid.

This month it will be moving slowly southwestward in Aquarius. Peak brightness occurred at opposition on Sept. 22 when Juno was as bright as magnitude 7.6. In November it will fade from magnitude 8.4 to 8.9. Twenty degrees or so to the east of Juno is another bright asteroid, (18) Melpomene which is described in its own section.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Juno from Heavens Above.

(18) Melpomene

About 25 degrees to the east of (3) Juno lies another nice asteroid target for small telescopes. (18) Melpomene is located in the constellation of Cetus and is roughly the same brightness as Juno, in November it will fade from magnitude 8.3 to 9.0.

Melpomene is another stoney S-type asteroid and similar to Iris was also discovered by John Russel Hind. Found in 1852, it is his 5th of 10 asteroid discoveries.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Iris from Heavens Above.

(4) Vesta

Though not as large as Ceres, Vesta is more reflective making it the brightest asteroid in the Main Belt. Vesta is peculiar in that it appears to have evidence of volcanism on its surface. Similar to the Moon, Vesta may be covered with large expanses of frozen lava flows. It is classified as a V-type asteroid and is the only large asteroid with this classification. Many of the smaller V-type asteroids are chips of Vesta blasted off it by past asteroid and comet impacts. Vesta is similar in size to Pallas with dimensions of 347×336x275 miles or 578×560×458 km. Vesta will also be visited by NASA’s Dawn spacecraft which will arrive in 2010.

Vesta is once again observable in the morning sky before the start of dawn. It is brightening from magnitude 8.1 to 7.7 as it travels eastward just north of Regulus in Leo.

A finder chart (needs to be flipped upside down for Northern Hemisphere observers) can be found at the Royal Astronomical Society of New Zealand. Finder chart for Vesta from Heavens Above.

Nov 18/19/20 Meteors November 22, 2008

Posted by Carl Hergenrother in Meteors.
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The rate of Leonids is falling after Monday morning’s peak. Though the Leonids put on a great show for those in Europe, the Moon and low non-outburst rates made for a less than exciting display over the States.

I wasn’t able to get any data on the night of Nov 18/19. The reason? Operator failure. I forgot to turn the camera on. I usually double check these things but didn’t that night.

From Bob Lunsford’s notes: “Leonid rates increased a bit as expected on the morning of the 19th. They still fell well short of what was seen on the morning of the 17th. Rates fell by two-thirds on the 20th and now only a few Leonids will appear each morning until they disappear for another year. Overall meteor totals are improving as the moon wanes and becomes less of a nuisance.”

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO AMO
TUS  2008-11-20  11h 11m  24  12  4   4   4   0
SDG  2008-11-20  11h 39m  76  57  8   2   6   3
TUS  2008-11-19  00h 00h
SDG  2008-11-19  08h 34m  64  36  3   5  18   2

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids
AMO – Alpha Monocerotids

Nov 17/18 Meteors November 18, 2008

Posted by Carl Hergenrother in Meteors.
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Leonid rates were much lower last night when compared to the morning of the 17th. With the possibility of some enhancement tonight, hopefully we’ll see some higher Leonid rates. After this week, the Leonids should be history and then we can look forward to December’s big showers, the Geminids and the Ursids.

From Bob Lunsford’s notes: “Leonid rates were down quite a bit compared to the 17th. It appears that the declining portions of the European outburst were visible from North America on the morning of the 17th. I would expect a few more Leonids on the 19th vs. the 18th and then low rates during the remainder of its activity profile.”

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO AMO
TUS  2008-11-18  11h 11m  30  17  1   2   8   2
SDG  2008-11-18  11h 35m  78  46  9   9   12  2

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids
AMO – Alpha Monocerotids

Nov 16/17 Meteors and the Peak of the Leonids November 17, 2008

Posted by Carl Hergenrother in Meteor Outburst, Meteors.
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In yesterday’s “The November Meteor Storms – Part II – The Leonids” posting, it was mentioned that there were a few chances for elevated activity last night for Europe and Asia. Mikhail Maslov predicted a high rate of Leonids for an hour or so on either side of 00h 22m UT on November 17. Jérémie Vaubaillon also predicted elevated rates of Leonids centered at 01h 32m UT on November 17. According to Vaubaillon, the high rates would be due to the Earth crossing a trail of dust released by Comet Tempel-Tuttle in 1466.

According to the International Meteor Organization’s Leonids 2008 Live webpage, a nice outburst of Leonids was observed at ~02h 00m UT on November 17. Based on the Leonids Live page and posts to the Meteorobs list at Yahoo Groups, observers in Europe and Israel witnessed the outburst. Rates may have reached as high as ZHR=~130.

By the time the Leonids were visible from the United States, the outburst was over. The 23 Leonids seen by my Tucson-based camera show that no outburst was visible over Tucson. Bob’s tally of 30 Leonids over San Diego also confirms this. Comparing video rates with naked eye observeing rates is tricky. Last month, when my camera detected roughly ~23 Orionids in a night, the visual observers were measuring ZHRs (zenithal hourly rate) of 10-20. So, with a bit of hand waving, the Leonids were falling at a ZHR of 10-20 over the western US last night. This is the expected rate for the Leonids when no elevated activity is seen. As you will see in Bob’s comments, his experience is that the Leonids will continue to strengthen till the morning of the 19th. So maybe there is more to come.

From Bob Lunsford’s notes: “The weather continues to cooperate in San Diego. I had the camera on from dusk to dawn and recorded 87 meteors. The first Leonid was recorded at 12:30 am PST and 29 more were caught the remainder of the night. That is an average of roughly 6 Leonids per hour. While Carl has mentioned the possibility of enhance rates may seen from the eastern hemisphere on the 17th, my personal data show that the strongest Leonid rates have been occurring on the morning of November 19th. We will have to see what actually happens.”

Jérémie Vaubaillon predicts the possibility of another period of elevated Leonid activity at 21:38 UT on November 18 though rates will may not be as high as those seen last night over Europe. This “outburst” will be observable over Asia.

Below are 2 movies from Tucson. The 1st shows the brightest Leonid (or meteor of any kind) observed by my Tucson-based camera last night. This doesn’t mean that there weren’t even brighter meteors observable over Tucson. My camera only covers a small fraction of the sky so I do miss a lot of meteors.

12421

The 2nd movie shows 47 of the meteors detected by my Tucson-based camera. The camera is fixed so you can easily see the stars and the Moon moving from East to West through the field. The big white blob moving along the bottom of the frame is the Moon.

leo5

Movie of 47 meteors (includind 23 Leonids) seen by the SALSA camera over Tucson on the night of November 16/17 MST. The big bright blob in the bottom of most frames is the Moon.

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO AMO
TUS  2008-11-17  11h 33m  48  22  0   1   23  2
SDG  2008-11-17  11h 27m  87  45  6   5   30  1

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids
AMO – Alpha Monocerotids

Nov 15/16 Meteors November 16, 2008

Posted by Carl Hergenrother in Meteors.
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A good number of meteors were detected over Tucson and San Diego last night. Tonight (Nov 16/17) marks the peak of the Leonids and hopefully they will provide us with some surprises.

From Bob Lunsford’s notes: “It was another totally clear night in San Diego. I had a late start due to other commitments. I probably did not miss much as there are many more birds and bugs seen in the evening skies compared to meteors. The Leonid rates are getting interesting. The Leonids are unmistakable on video as they are mostly swift and the brighter members leave persistent trains. The next few nights should provide many more.”

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO AMO
TUS  2008-11-16  11h 48m  37  21  6   2   8   0
SDG  2008-11-16  08h 16m  68  38  10  6   13  1

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids
AMO – Alpha Monocerotids

The Meteor Storms of November – Part II – The Leonids November 16, 2008

Posted by Carl Hergenrother in Meteor Outburst, Meteors.
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The Leonids are the meteor storm-producing shower against which all other showers are measured. Most years the Leonids are a rather minor shower producing up to 15 meteors per hour, but on occasion they can produce some of the most spectacular meteor displays ever seen.

Comet 55P/Tempel-Tuttle, The Leonid Parent Comet

The Leonids are the result of dust released by Comet Tempel-Tuttle. Similar to the stories of the discoveries of Comets Encke (parent of the Taurids) and Biela (parent of the Andromedids), Comet Tempel-Tuttle was observed a few times before its periodic nature was noted. The first sighting happened way back in 1366 when the comet was observed by Chinese astronomers. Though the Chinese reported very accurate positions of the comet, especially impressive in an age without telescopes, the science of computing comet orbits had not yet been invented. Hence, there was no way to for them to know if this comet could return.

Fast forwarding a little over 3 centuries, Gottfried Kirch of Guben, Germany, finds a new comet on the night of 1699 October 26. Unfortunately, the comet is no where to be found on later nights. We now know that this was Comet Tempel-Tuttle and it was moving to the south so rapidly that the comet was not observable from Germany on the nights after Kirch’s discovery.

The comet would have to wait another ~167 years before it was found again. This time two of the 19th centuries premiere comet hunters, Ernest W. L. Tempel (Marseille, France) and Horace P. Tuttle (Cambridge, MA), found the comet almost 3 weeks apart. Tempel found the comet first on the night of 1865 December 19. Since news traveled slow in those days, the comet was independently discovered by Tuttle on 1866 January 9 before the news of Tempel’s discovery reached America. Not only was the periodic nature of the comet recognized at that time but so was its association with the Leonid meteors.

The comet resides on an orbit that spans from just inside the orbit of the Earth (0.98 AU) to slightly beyond the orbit of Uranus (19.7 AU). It takes the comet ~33 years to orbit the Sun. The the comet last passed perihelion (closest distance to the Sun) in 1998 and was well observed at that time.

tempel_tuttle_outer

Orbit of Comet Tempel-Tuttle and the Leonid meteors. Orbit diagram produced with the C2A planetarium program (http://www.astrosurf.com/c2a/english/index.htm)

The Leonids Roar

leonids-18331

The most famous depiction of the 1833 meteor storm actually produced in 1889 for the Adventist book Bible Readings for the Home Circle based on a first-person account of the 1833 storm by a minister, Joseph Harvey Waggoner on his way from Florida to New Orleans.

The first recorded appearance of the Leonids was in 902 AD when the shower was seen from Italy and Egypt. For the next few centuries, impressive Leonid displays were observed every 33 to 200 years or so.

Two Leonid storms stand out from all the others. On 1833 November 13, the entire eastern United States was awaken to a sight very few had every seen. The sky appeared to be filled with meteors. Modern researchers now know the cause of this outburst. It is estimated that a rate of up to ~70,000 meteors per hour was observed. That works out to ~20 meteor per second.

The 1833 storm marks the dawning of the modern age of meteor science. It was due to observations of this storm that astronomers first recognized that meteors originate in space. About 30 years later, after the discovery of Comets Swift-Tuttle (parent of the Perseids) and Tempel-Tuttle (the parent of the Leonids), the connection between comets and meteor showers was made.

The 1833 storm ranks as one of the 2 best meteor displays in recorded history. 133 years after the 1833 storm, the Leonids once again set the skies ablaze. On the night of 1966 November 17, the western United States experienced a storm just as strong as the 1833 storm.

When the comet returned in 1998, there were many predictions for spectacular Leonid activity. Though meteor rates never got close to that seen in 1833 or 1966, rates as high as a few thousand meteors per hour were observed in multiple years. The best meteor shower I have ever seen was the 1998 Leonid fireball display. Though I would observe Leonid displays with much higher rates of meteors, the sheer number of extremely bright meteors in 1998 was breathtaking.

Predictions for the 2008 Leonids

Now that it is over 10 years since the perihelion of Comet Tempel-Tuttle, what can we expect. In most years when the comet is not in the vicinity of Earth (which is true this year) the Leonids are a nice but relatively light shower with rates up to 15 meteors per hour.

This year the peak is predicted for the morning of November 17. But there are 2 predictions for enhanced activity this year. The International Meteor Organization summarizes this year’s prediction with the following taken from their 2008 Meteor Calendar:

The Leonids may produce just a normal maximum close to their ‘traditional’ nodal time in 2008, on November 17, around 09h UT, though the bright waning Moon will be a severe problem if so. However, Mikhail Maslov proposed that the shower may show a peak with ZHRs ~ 130 at 00h22m UT on November 17 in WGN 35:1 (2006, p. 7), with meteors brighter than average. Many of his other model calculations for the Leonids in the period 2001 — 2006 showed some differences to what was actually observed, so while this this is an interesting possibility for 2008, its accuracy is unknown and unproven. Jérémie Vaubaillon finds instead two potential stream encounters, centred on November 17 at 01h32m UT (1466 trail; ZHR most uncertain — perhaps ~ 50, but maybe ~ 25 — 100) and November 18 at 21h38m UT (1932 trail; ZHR possibly ~ 20 at best?). Checking on all these times (or any others that may be suggested subsequently) will be difficult due to the Moon, but valuable.

What does this mean? Most of us, especially in the United States, will only see the “normal” maximum on the morning of November 17 with low rates due to the bright Moon. For those located throughout Eurasia, one, two or three of the possible outbursts may be observable. The Leonids are best observed in the hours before sunrise and will appear to radiate from the western part of the constellation of Leo.

The International Meteor Organization has a “live” graph of reported Leonid activity at their website.

As for the future, we may have seen the end of the great Leonid storms. The orbits of the Leonids and Comet Tempel-Tuttle are slowly moving away from Earth due to the gravity of the planets. Though there may be Leonid displays with meteor rates as high as hundreds to a few thousand per hour around the time of Comet Tempel-Tuttle’s next perihelion in 2031, there will be no great storms. There is a possibility of one last hurrah for the Leonids around the time of its perihelion in 2131.

Nov 14/15 Meteors November 15, 2008

Posted by Carl Hergenrother in Meteors.
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From Bob Lunsford’s notes: “It remained clear all night long. The waning gibbous moon was riding high in Taurus, passing only 5 degrees south of the zenith. This morning we start recognizing activity from the Alpha Monocerotids, a normally weak shower that has produced several outbursts in the past. Rates are normally no better than several meteors per hour at best at maximum. Recording 4 this morning is surprising as I would have expected no more than 1 per night at this stage.”

If you read the last post about the Andromedid meteor storms, then you know that there are two other meteor storm producing showers in November. The Leonids and the Alpha Monocerotids are the other two and will be the focus of new posts in the coming days.

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO AMO
TUS  2008-11-15  11h 24m  28  16  1   5   6   0
SDG  2008-11-15  11h 33m  71  44  11  4   8   4

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids
AMO – Alpha Monocerotids

Nov 12/13/14 Meteors November 14, 2008

Posted by Carl Hergenrother in Meteors.
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The night of Nov 12/13 was plagued by high cirrus at both the Tucson and San Diego sites. The cirrus was so bad at Tucson that only 3 meteors were picked up the entire night.

Last night (Nov 13/14) was much better with clear skies in San Diego and only a few short bouts of cirrus in Tucson. As a result, a good number of meteors were seen in spite of a very bright near Full moon.

The Leonids continue to build towards there peak early next week.

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO
TUS  2008-11-14  11h 33m  26  14  2   4   6
SDG  2008-11-14  11h 35m  70  51  6   3   10
TUS  2008-11-13  09h 28m  3   3   0   0   0
SDG  2008-11-13  11h 29m  43  25  5   6   7

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids

Nov 11/12 Meteors November 12, 2008

Posted by Carl Hergenrother in Meteors.
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Bob’s notes from last night say it all… “Cirrus clouds produce nice sunrises and sunsets but they wreck havoc on meteor observations, especially when the moon is full and bright. Such was the case last night as seen from the San Diego area. The bright moon and thin cirrus obscured more than one half of the expected activity. Luckily the forecast calls for clear skies the remainder of the week and through the weekend.”

In Tucson, conditions were a little better though cirrus wrecked the observing early in the night (I didn’t even bother turning on the camera for the first few hours) and for a stretch in the middle of the night.

It was a good night for the Taurids, especially the Southern branch. We are also picking up a good number of Leonids though these are very much end-of-the-night meteors.

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO
TUS  2008-11-12  07h 28m  24  11  1   9   3
SDG  2008-11-12  08h 26m  41  27  4   8   2

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids

Nov 8/9/10/11 Meteors and Bouts of Clouds November 11, 2008

Posted by Carl Hergenrother in Meteors.
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The past few nights have  been tough for meteor observing in both Tucson and San Diego. Rain fell in San Diego during the early morning of the 9th. Those showers, and thunderstorms, made their way to Tucson by the next evening. When not raining, there were enough clouds to make sky watching tough. This is especially true when the Moon is bright and illuminating the clouds.

Now as much as I’d like to get observations every night, we really need rain here. Tucson, like much of western North America, is in the grips of a decade-long drought. Hopefully we’ll lose some more nights to rain this winter.

From Bob’s notes on the 9th/10th: “Skies were clear on the evening of the 8th when I went to sleep but I woke during the morning hours to the sound of raindrops. That’s the wrong kind of showers! It rained off and on the remainder of the night and throughout the day. Skies began to clear near dusk on Sunday but it was not clear enough to run the camera until after 9pm. These rates are highly reduced due to clouds. The first two Leonids made their appearance on the morning of the 10th.”

And from the 11th: “Skies were partly cloudy all day and into the early evening. They finally cleared near 10pm and skies were mostly clear the remainder of the night. But now the moon is near its full phase so meteor rates will be reduced while the bright moon is high in the sky.”

Obs  Date (UT)   TotTime TOT SPO NTA STA LEO
TUS  2008-11-11  07h 13m  10  9   1   0   0
SDG  2008-11-11  07h 13m  51  36  6   3   6
TUS  2008-11-10  03h 57m  8   7   0   1   0
SDG  2008-11-10  08h 08m  30  21  4   3   2
TUS  2008-11-09  11h 39m  21  16  1   4
SDG  2008-11-09  08h 41m  11  5   3   3

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)
NTA – Northern Taurids
STA – Southern Taurids
LEO – Leonids