Nov 24/25/26/27 Meteors

As the rain falls (a little) on Tucson, I’ll let Bob summarize the meteor totals over the past few nights.

Bob’ notes for the night of Nov 26/27 : “Rates were down significantly tonight with big drops in the NTA’s and sporadics. The waxing gibbous moon is starting to take it’s toll on sky conditions and reducing meteor rates.”

… for the night of Nov 25/26 : “It was another totally clear night. Totals were similar to yesterday but without the wide swings in activity. The Northern Taurids were especially strong tonight producing 21% of the total activity.”

… for the night of Nov 24/25 : “Another totally clear night. Totals were similar to yesterday but the hourly rates were quite variable with wide swings in activity. The evening hours were unusually quiet. Perhaps the first quarter moon is beginning to show its effects. This was the last night for Alpha Monocerotid activity. While we say goodbye to this shower tomorrow we welcome the more active Sigma Hydrids, which peak on December 6th.”

Obs  Date(UT)      Time    TOT SPO ANT NTA STA LEO AMO NOO AND HYD
TUS  2009-11-27   11h58m    29  18  1   -   -   2   -   6   0   0
SDG  2009-11-27   11h46m    53  38  -   7   -   1   -   4   1   2
TUS  2009-11-26   12h00m    47  35  3   -   -   2   -   10  0   0
SDG  2009-11-26   11h52m    70  46  -   15  -   3   -   3   1   2
TUS  2009-11-25   11h58m    45  31  -   1   3   3   3   4   0   -
SDG  2009-11-25   11h49m    64  41  -   9   -   4   3   5   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/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids

Nov 21/22/23/24 Meteors

Nightly rates remain high which is not unusual for this time of the year. The brightening Moon should start to suppress the number of meteors which can be seen.

Bob’ notes for the night of Nov 23/24 : “It was a brilliantly clear night and meteor rates were near what is expected this time of year.”

… for the night of Nov 22/23 : “Skies cleared up nicely compared to last night. Meteor totals were a bit less than what was expected with the nice, transparent skies.”

… for the night of Nov 21/22 : “Clouds largely spoiled tonight’s observations. The start was delayed by clouds. The sky cleared near 9pm PST and it remained mostly clear for the next 4 hours. It clouded up again near 1am PST and remained cloudy the remainder of the night.”

Obs  Date(UT)      Time    TOT SPO NTA STA LEO AMO NOO AND
TUS  2009-11-24   11h35m    47  25  7   1   7   3   2   2
SDG  2009-11-24   11h49m    66  49  7   -   4   1   3   2
TUS  2009-11-23   11h20m    54  36  1   4   6   5   2   0
SDG  2009-11-23   11h46m    51  36  7   -   2   2   3   1
TUS  2009-11-22   11h34m    47  29  3   1   4   5   4   1
SDG  2009-11-22   04h00m    11  5   3   -   0   1   2   0

TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
NTA/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids

Nov 20/21 Meteors

Clouds have started to creep back into the American Southwest. Though they were little more than a temporary nuisance in Tucson, they cut Bob’s night in half at his  sight in San Diego. The Leonids are still hanging on at a much reduced level from earlier in the week. The Tucson cameras also appeared to pick up some healthy activity from the Alpha Monocerotids which were predicted to be near their peak last night.

Bob’ notes for the night of Nov 20/21 : “It was clear up to 0700 UT (11pm PST). After that it was partly cloudy for most of the remainder of the night. After 1200 UT (4am PST) it was almost totally overcast. Meteor totals were only half of what was recorded the previous night. The weather forecast is for more favorable skies tonight through the Thanksgiving holiday.”

Obs  Date(UT)      Time    TOT SPO NTA STA LEO AMO NOO AND OER
TUS  2009-11-21   07h59m    48  24  1   1   8   7   4   0   2
SDG  2009-11-21   10h55m    31  22  5   -   1   0   3   0   -

TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
NTA/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids
OER – Omicron Eridanids

Nov 19/20 Meteors

The Leonids are becoming much fewer in number. Still the relatively high number of Sporadic meteors is keeping the nightly totals elevated.

My 2 cameras produced an interesting result last night. The zenith (straight-up) camera found a half-dozen or more meteors that appeared to radiate from a broad area on the Ursa Major/Lynx border. But, the north camera, which also happened to directly image the supposed “radiant” saw nothing from that area. The lack of agreement between the two cameras suggests that either a) this was just a fluke alignment, or b) bad astrometry and these were actually Leonids, or c) there was an unknown shower active last night. Personally I believe explanation ‘a’.

Bob’ notes for the night of Nov 19/20 : “It was clear and transparent all night long. Rates were back up to what was expected. The Northern Taurids were the most active shower surpassing the Leonids.”

Obs  Date(UT)  Time    TOT SPO NTA STA LEO AMO NOO AND OER
TUS  Nov-20   11h52m    52  28  4   3   11  2   2   1   1
SDG  Nov-20   11h55m    66  44  9   -   6   2   4   0   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/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids
OER – Omicron Eridanids

Update on Nova V496 Scuti

Nova V496 Scuti is still near maximum brightness at magnitude ~7.4. For the back story on this object check out my post from Nov 15: “Nova Scuti 2009 = V496 Scuti“.

The plot below was created by the American Association of Variable Star Observers (AAVSO) from their archives. It includes 97 observations made by 33 observers from 13 countries. The blue crosses represent my own observations which were made visually with 30×125 binoculars. You can also check out Salvador Aguirre’s blog (in Spanish) for his observations of V496 Scuti.

The nova has been rather steady in its brightness for the past 5 days or so. Based on the data below, it’s possible it is still slowly brightening. Regardless, at some point in the next week or so, the nova should start to rapidly fade. I say should because some nova have been known to stay bright for weeks to months and even experience multiple outbursts.

AAVSO archival data of nova V496 Scuti. Credit: AAVSO (www.aavso.org)

Meteor Activity Outlook for November 21-27, 2009

The Meteor Activity Outlook is a weekly summary of expected meteor activity written by Robert Lunsford, Operations Manager of the American Meteor Society and contributor to this blog. The original unedited version of this week’s Meteor Activity Outlook can be found at the American Meteor Society’s site.

As seen from the northern hemisphere, meteor rates continue to be strong in November. While no major showers are active this month, the two Taurid radiants plus the Leonids keep the skies active. The addition of strong sporadic rates make November one of the better months to view meteor activity from north of the equator. Skies are fairly quiet as seen from the southern hemisphere this month. Activity from the three showers mentioned above may be seen from south of the equator, but the sporadic rates are much lower than those seen in the northern hemisphere.

During this period the moon reaches its first quarter phase on Tuesday November 24th. On that date the moon lies ninety degrees east of the sun and will set near midnight local standard time (LST). This weekend the waxing crescent moon will set long before the more active morning hours arrive, allowing dark skies for those who venture out during the morning hours. As the week progresses the moon sets later each night narrowing the window of opportunity to view under dark conditions. The estimated total hourly rates for evening observers this week is near four as seen from the northern hemisphere and three from the southern hemisphere. For morning observers the estimated total hourly rates should be near twenty from the northern hemisphere and ten as seen from the southern hemisphere. The actual rates will also depend on factors such as personal light and motion perception, local weather conditions, alertness and experience in watching meteor activity. Rates are reduced during the evening hours due to moonlight.

The radiant positions and rates listed below are exact for Saturday night/Sunday morning November 21/22. 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.

Andromedids (AND)

Sirko Molau’s studies of video radiants has revealed that activity from the famous Andromedid shower, noted for intense storms during the 19th century, may still be seen throughout November. This position lies in eastern Andromeda, two degrees south of the fourth magnitude star Nu Andromedae. The nearest bright star is second magnitude Almach (Gamma Andromedae), which lies four degrees to the northeast. Visual activity is expected to be low, but detectable. The Andromedid radiant is best placed near 2200 (10pm) local standard time (LST) when it lies on the meridian. At 19km/sec., the average Andromedid will appear as a very slow moving meteor. Sirko mentions that these meteors are “conspicuously slow and of almost constant activity” during this period.

Northern Taurids (NTA)

The Northern Taurids (NTA) are active from a large radiant centered at 04:29 (067) +24, which lies in northern Taurus, eight degrees north of the orange first magnitude star Aldebaran (Alpha Tauri). The radiant is best placed near 0100 LST, when it lies highest above the horizon, but activity may be seen all night long. Meteors from the Northern Taurids strike the atmosphere at 29km/sec., which would produce meteors of slow velocity. Expected rates would be ~3 per hour as seen from the northern hemisphere and ~2 per hour as seen south of the equator.

November Orionids (NOO)

The November Orionids (NOO) were recently discovered by analyzing video data. This shower is active from November 18 through December 9. Maximum activity occurs on November 30. The radiant is currently (11/18) located at 05:44 (086) +15. This position lies on the Orion/Taurus border, six degrees north of the third magnitude star Lambda Orionis. These meteors are also best seen near 0300 LST when the radiant lies on the meridian and highest above the horizon. At 44 km/sec. the November Orionids produce mostly medium velocity meteors.

Alpha Monocerotids (AMO)

The Alpha Monocerotids (AMO) are active from November 15-25, with maximum occurring on the 21st. This shower has produced outbursts in the past but none are expected for many years to come. Rates are expected to be < 1 shower member per hour, even on the night of maximum activity. The radiant is currently located at 07:52 (118) +01. This position lies in southeastern Canis Minor, five degrees southeast of the zero magnitude star Procyon (Alpha Canis Minoris). These meteors are also best seen near 0500 LST when the radiant lies highest above the horizon in a dark sky. At 65 km/sec. the Alpha Monocerotids produce mostly swift meteors.

Leonids (LEO)

The Leonids (LEO) reached maximum activity on the morning of November 17th with ZHR’s exceeding 100 as seen over Asia. Current rates would be near one per hour no matter your location. The radiant is currently located at 10:27 (157) +20. This position lies in western Leo, just one degree northeast of the famous second magnitude double star Algeiba (Gamma Leonis). At 70km/sec., the average Leonid is swift with a high percentage of trains. The radiant does not rise until the late evening hours so it is advised to wait until after midnight before beginning serious observations. The radiant is most favorably located during the last dark hour before the onset of morning twilight when it lies highest in a dark sky.

As seen from the mid-northern hemisphere (45N) one would expect to see ~16 Sporadic meteors per hour during the last hour before dawn as seen from rural observing sites. Evening rates would be ~3 per hour. As seen from the mid-southern hemisphere (45S), morning rates would be ~6 per hour as seen from rural observing sites and ~2 per hour during the evening hours. Locations between these two extremes would see activity between the listed figures.

The table below presents a condensed version of the expected activity this week. Rates and positions are exact for Saturday night/Sunday morning but may be used all week long.

Shower Name                RA     DEC   Vel     Rates
                                        km/s   NH    SH
AND Andromedids          01h 38m  +39    19    <1    <1
NTA Northern Taurids     04h 29m  +24    29     3     2
AMO Alpha Monocerotids   07h 52m  +01    65    <1    <1
LEO Leonids              10h 27m  +20    70     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

Nov 18/19 Meteors

Leonid activity is rapidly decreasing in intensity with rates less than half of what they were just a night ago. Still the nights are producing lots of meteors. Last night saw a large number of “long” meteors that traveled over 20 degrees of sky. The best example can be seen in the video below. This sporadic meteor was seen at 9:22 pm MST (4:22 UT). It actually starts in the FOV of my zenith camera before moving far enough north to enter the FOV of my northern camera (the video below is from the north camera). If you look closely at the beginning of the video you will notice material falling off the meteor. Unfortunately my system dropped a few frames which is why the meteor appears to jump ahead a few times.

Bob’ notes for the night of Nov 18/19 : “Clouds plagued observations most of the night so meteor numbers are far below what they should be.”

Obs  Date(UT)  Time    TOT SPO NTA STA LEO AMO NOO AND OER
TUS  Nov-19   11h51m    69  35  4   4   17  2   5   1   1
SDG  Nov-19   07h42m    37  25  2   2   8   0   2   0   0

TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
NTA/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids
OER – Omicron Eridanids

Nov 17/18 Meteors and the Leonids over Asia

As predicted, the Earth’s passage through the 1466 and 1533 dust trails of Comet Tempel-Tuttle resulted in enhanced Leonid activity. Due to the time when the activity occurred, it was only visible to observers in Asia. Visual reports to the International Meteor Organization (IMO) suggest a peak around 20-21 hours UT with rates 80-140 per hour. This matches the lower values predicted by computer models. Though early predictions called for 500-1000 meteors per hour, recent revisions brought the predicted rates down to 100-200 per hour. The plot below from the IMO shows rate of activity for the past few days (you should be able to click on the plot to expand it).

Visual ZHR for the Leonids. Credit: International Meteor Organization.

Even though rates of 100+ meteors per hour are great and real fun to watch, they are not high enough to be considered a meteor storm. In fact they are comparable to the peak activity ofthe annual Perseid and Geminid showers. So if you missed the Leonids at their best, don’t worry, the Geminids will be just as good in a few weeks (Dec 13/14).

Last night’s video data shows activity levels that were a bit lower than the night before. As the IMO plot above shows, the times when the Leonids were observable from my site (~8 to 13 hours UT) bracket the peak activity. For the last 2 nights, Leonid activity over the US has been moderate with ZHRs of 20-30 per hour. Rates should gradually decrease as we move away from the Leonid dust trails.

Bob’ notes for the night of Nov 17/18 : “Last night saw fog rushing in at dusk only to retreat shortly thereafter. This went on all night long therefore rates are slightly down compared to yesterday. The Leonids were down significantly from the previous night. I would expect a slight improvement in Leonid rates on the 19th. After a good showing last night. the Andromedids failed to appear tonight.”

Obs Date(UT)Time  TOT SPO NTA STA LEO AMO NOO AND OER
TUS Nov-18 11h12m  81  22  3   1   40  5   2   1   1
SDG Nov-18 11h40m  62  28  6   2   20  3   2   0   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/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids
OER – Omicron Eridanids

Utah Fireball – November 18

A brilliant fireball was seen over Utah a few minutes past midnight last night. Video images give the time of the fireball as ~12:07 am MST (7:07 UT). At least 2 comments to this blog describe the event.

Miah wrote:

Did you guys see the one in Bountiful Utah a half an hour ago Nov. 18th 2009 12:12 A.M. It had to be at least 30 feet wide with a fire blazing tail that lasted for a couple of seconds stringing out at least a mile long and it lit up the dark night like it was a really bright sunny day. The kind of day you really need to wear sunglasses from horizon to horizon for at least 6 seconds it threw my heart up into my throat and I received an immediate and outrageous adrenalin rush. This experience was by far the coolest thing I have ever seen in the night sky. If anybody else saw this please post and I really hope someone or somebodys business buildings camera got this on tape and they post it soon. I really want to relive that moment again… All I can say is WOW…

and Melissa wrote:

i was at walmart shopping and when i came out to put my items away the whole sky lit up like it was morning for about 3 seconds and then i turned around and then things got dark again and i saw an orange tail in the sky looked like fire and then it was gone it was so weird and scary

KSL TV has a whole bunch of videos listed on their website. Especially check out Patrick Wiggins video where he gives a great and thorough explanation of what the fireball was. Some of the videos show the actual fireball in the sky while others show the ground being lit up as bright as day. Further news stories can be found at The Salt Lake Tribune and Spaceweather.com.

Six or so hours later, as the sun was rising, a ghostly blue trail was observed over Utah. This trail appears similar to those seen after other bright fireballs. What is amazing is that trail had not dissipated after such a long time. Note, the crazy meandering pattern of the trail does not mean the fireball was moving erratically. The erratic pattern of the trail is due to varying wind speeds and directions in the upper atmosphere.

So far I have not seen any images or videos of the fireball. All the videos and images just show the ground or sky lighting up. As Miah wrote above, the fireball lit up the ground as bright as day.

Though it was probably below the horizon as seen from Tucson, the sky did brighten towards the north. My north facing meteor camera did detect a brightening of the northern sky. Though I recognized it as something unusual when I looked over the data this morning, I deleted the data since there was no obvious meteor in the field. Only later did I read about the Utah fireball. Luckily the MMT all-sky cam picked up the flash from Mount Hopkins, just south of Tucson. The flash was observed to the north at the exact time of the fireball so there is no doubt they are related. If the flash was seen as far south as Tucson, it is likely that it was also seen from a wide area including the states of UT, AZ, NM, CO, WY, ID, CA,NV, and OR.

Though the fireball occurred at a time when the Leonids were at their best, it is doubtful it is related to the Leonids. The Leonids are extremely fast meteors, in fact they are almost as fast as meteors can get (~70 km/s). As a result, Leonids rarely last more than a second and usually burn out in one very quick burst. The fact that this fireball lasted for some time (~5 seconds) means it was a much slower meteor that probably descended to a low altitude (~20-50 km). It is more likely it was caused by a small (0.5 to 2 meter) asteroid.

Nov 16/17 Meteors and a good Leonid display

Last night the Leonids put on a respectable show. My 2 cameras detected 45 Leonids which was about 40% of the number of Orionids observed during that shower’s  peak last month. Though this comparison is an apples-to-oranges comparison it does suggest that Leonid visual rates were on the order of a ZHR of ~20. (Remember this rate, called the Zenithal Hourly Rate, is valid for a dark rural sky and when the radiant is overhead, most observers will be observing under worse conditions and will see fewer meteors.)

Last night visual observers detected a rate of up to ~36 Leonids per hour from a dark site.  This value will change as more data rolls in. Check out the IMO’s Live ZHR Leonids page to see the latest activity rates.

I was one of those visual observers out watching the meteors. From 9:41 to 12:51 UT (little over 3 hours) I counted 51 meteors, of which 38 were Leonids. These observations were made under a sky with a limiting magnitude of +5.5. It really was a tale of 2 showers. For the 1st hour, not much was going on with only 7 Leonids sighted. The 2nd hour saw active pick up big time. Between 10:52 UT and 12:18 UT 24 Leonids were seen. On 2 separate occasions 2 meteors were observed at the same time. By the end of the night activity seemed to be settling down. The plot below shows the distribution of Leonids in 10 minute intervals.

 

Compare the above plot with the distribution of video meteors. The video plot starts earlier so the range on the x-axis does not match in the 2 plots.Though the video data also shows low activity early on, this is most likely due to the low altitude of the radiant. Whereas the visual data doesn’t show an uptick in activity until ~10:50 UT, the video data shows a steady increase in activity from about ~9:30 UT onwards. The falloff in activity at the end of the night in both the visual and video data may be due to the brightening sky rather than a true reduction in rates.

The best meteor of the night was a brilliant fireball that occurred around 11:54 UT. I usually observe towards the north because that is the only part of the sky that is not obscured by trees in my yard. For a split second, the house was lit up by an obvious bright meteor to the south of me. Even though I didn’t directly see the fireball and it was out of the FOV of my cameras, 2 other cameras did pick up the fireball. Jim Scotti set-up his DSLR to take near all-sky images of the sky. One of his images captured the fireball streaking through Orion. Even half and hour later, the dust train produced by the fireball was still visible. Go here for Jim’s picture of the fireball and the resulting train.

The fireball was also picked up by the MMT all-sky camera. In the image below the fireball is seen moving behind the MMT’s dome.

According to the published predictions, enhanced activity should have been seen over Asia. For us, tomorrow should provide lower rates than last night.

Bob’ notes for the night: “The Leonids doubled their totals from last night with 30 shower members being recorded. Several bright sporadics are also suspected of being Leonids. A surprising 5 Andromedids were recorded. The normal is only 1-2 per night. No Omicron Eridanids (OER) were recorded last night.”

Obs Date(UT)Time  TOT SPO NTA STA LEO AMO NOO AND OER
TUS Nov-17 11h41m 111  38  11  3   45  3   0   1   0
SDG Nov-17 11h11m  79  32  5   2   30  2   3   5   0

TUS – Camera in Tucson operated by Carl Hergenrother
SDG – Camera in San Diego operated by Bob Lunsford
TotTime – Total amount of time each camera looked for meteors
TOT – Total number of meteors detected
SPO – Sporadics (meteors not affiliated with any particular meteor shower)
NTA/STA – Northern and Southern Taurids (includes Antihelions)
LEO – Leonids
AMO – Alpha Monocerotids
NOO – November Orionids
AND – Andromedids
OER – Omicron Eridanids

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