July 24-25 Meteors

The monsoon has been on hiatus here in Tucson and finally we had two relatively clear nights. There were still a few clouds and last night was very murky with lots of dust coming up from Sonora thanks to a strong Gulf of California surge. (If you’re interested, the Madweather blog is a great source for understanding the weather in southeastern Arizona.)

The Southern Delta Aquariids and Alpha Capricornids are the most active showers. A handful of meteors was also seen from the Perseids radiant though they might also be Psi Cassiopeiids as mention in the previous post.

The monsoon moisture has raced back into Tucson today so tonight will probably involve more battles with the weather.

 

Obs Date(UT)    Time   TOT SPO ANT PPS SCA CAP JPE PAU PER ZED SDA SIA ERI
SAL 2014-07-25 05h 45m  16  6   0   0   -   2   1   0   0   1   4   0   0
SAL 2014-07-24 07h 30m  19  9   0   0   2   3   0   0   3   1   0   0   1
                           also no MUL or GDR were seen over the 2 nights

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors 
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PPS - Phi Piscids
SCA - Sigma Capricornids
CAP - Alpha Capricornids
JPE - July Pegasids
PAU - Piscis Austrinids
PER - Perseids
ZED - July Zeta Draconids
SDA - Southern Delta Aquariids
SIA - Southern Iota Aquariids
ERI - Eta Eridanids
MUL - Mu Lyrids
GDR - July Gamma Draconids

July 16-23 Meteors

Talk about a lot of active meteor showers. I had a hard time fitting all of the data in the table below.

Though the weather has still been poor in Tucson we did get a good clear night on July 22 (actually the night of July 21/22) with 24 meteors detected. That night also marked a change in my meteor camera system. I had to replace the outdoor housing because the old one was leaking badly. The change meant repointing the camera and reproducing an astrometric solution. I also took the opportunity to fiddle with the contrast and brightness of the video which should result in more meteors being detected.

The past week saw the start of two of the better showers of the summer, the Perseids (PER) and Southern Delta Aquariids (SDA). The Perseids should be known to most of you as one of the best annual showers. This year they peak on the night of August 12/13. Unfortunately the Moon will be very bright and will hinder any Perseid watching this year.

The other good shower are the Southern Delta Aquariids (SDA). This shower is one of the better showers for Southern Hemisphere observers but are still good for northerners too. The SDAs do not produce a lot of meteors, only ZHRs of 15-20 at their peak versus 60-120 for the Perseids. Still you may notice quite a few SDAs radiating from the area of Aquarius and Capricornus. The Alpha Capricornids (CAP), PAU (Piscis Austrinids) and SIA (Southern Iota Aquariids) are also active from the same region.

There has been some chatter on the meteorobs mailing list about a large number of Psi Cassiopeiids (PCA) detected by the Canadian Meteor Orbit Radar (CMOR). Surprisingly few of these meteors have been detected by visual and video observers. Over the past two nights perhaps 1 or 2 of my 34 detections have come from this shower. This suggests that these meteors are too faint for video (LM ~ +3) and visual (LM ~ +5) observers but not too faint for radar (LM ~ +8). The CMOR data also shows activity from the SDAs and CAPs.

equatorial

Plot of meteor radiants from the Canadian Meteor Orbit Radar (CMOR). The display is Earth-centric in RA/DEC space with opposition at 0 deg longitude and the Sun at 180 deg. Plot is from the ASGARD Web Log (http://fireballs.ndc.nasa.gov/).

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Obs Date(UT)    Time   TOT SPO ANT PPS SCA CAN CAP JPE PAU PER ODR ZED SDA SIA
SAL 2014-07-23 01h 10m  10  4   0   1   0   -   1   0   0   0   0   0   4   0
SAL 2014-07-22 08h 46m  24  16  1   1   0   -   2   0   0   1   0   1   1   1
SAL 2014-07-21 01h 17m  3   2   0   0   0   0   1   0   0   0   0   0   0   0
SAL 2014-07-20 06h 43m  4   3   0   0   1   0   0   0   0   0   0   0   -   -
SAL 2014-07-19 01h 10m  1   1   0   0   0   0   0   0   0   0   0   0   -   -
SAL 2014-07-18 05h 59m  9   5   0   0   1   0   1   0   0   2   0   -   -   -
SAL 2014-07-17 01h 12m  5   2   0   1   0   0   1   0   0   1   0   -   -   -
SAL 2014-07-16 01h 28m  10  4   1   1   1   1   1   1   0   -   -   -   -   -

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors 
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PPS - Phi Piscids
SCA - Sigma Capricornids
CAN - c Andromedids
CAP - Alpha Capricornids
JPE - July Pegasids
PAU - Piscis Austrinids
PER - Perseids
ODR - Omicron Draconids
ZED - July Zeta Draconids
SDA - Southern Delta Aquariids
SIA - Southern Iota Aquariids

July 7-15 Meteors

I wish I had more to report, meteor-wise, but it has been a rather cloudy monsoon season here in Tucson. That’s even considering it hasn’t rained much. It seems like every day is fairly clear but a nice cap of clouds form at night. As a result, many nights result in only a single meteor detection or none at all.

July is a fun month to watch meteors as many showers are active. The 6 showers listed below (in addition to the always present Sporadics and Antihelions) are just the best of a large number of showers visible this month.

Obs  Date(UT)      Time    TOT SPO ANT PPS SCA CAN CAP MIC JPE
SAL  2014-07-15   00h 00m        --- Clouds All Night ---
SAL  2014-07-14   00h 17m   1   1   0   0   0   0   0   0   0
SAL  2014-07-13   02h 05m   3   2   0   0   1   0   0   0   0
SAL  2014-07-12   01h 24m   7   6   0   0   0   0   0   0   1 
SAL  2014-07-11   00h 16m   1   1   0   0   0   0   0   0   0
SAL  2014-07-10   00h 10m   1   1   0   0   0   0   0   0   0
SAL  2014-07-09   07h 49m   1   1   0   0   0   0   0   0   0
SAL  2014-07-08   02h 46m   12  6   0   3   0   1   0   1   1
SAL  2014-07-07   07m 13m   7   4   0   0   1   0   0   1   1

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors 
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PPS - Phi Piscids
SSS - Southern Sigma Sagittariids
SCA - Sigma Capricornids
CAN - c Andromedids
CAP - Alpha Capricornids
MIC - Microscopiids
JPE - July Pegasids

July 1-6 Meteors

The monsoon is here. For most of the year, my priority is on counting photons or meteors. But in July and August, the name of the game is counting raindrops. As you can see by the rapid drop-off in detected meteors, the moisture (and resulting clouds) came in on July 2 (or more accurately the night of July 1/2). It wasn’t till yesterday that we got a good rain here at the house when 0.85″ fell (0.80″ of which fell in about 20 minutes during a late afternoon thunderstorm).

Unfortunately, my all-weather camera housing is no longer all-weather. A bit of rain made its way into the housing. Not enough to damage the camera but since this housing was on its last legs (lifetime extended with a few manual tinkering) I’ve decided to purchase a new home for the camera system.

 

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Obs  Date(UT)      Time    TOT SPO ANT PPS SCA JBO CAN CAP MIC JPE
SAL  2014-07-06   00h 00m        --- Clouds All Night ---
SAL  2014-07-05   00h 10m   1   1   0   0   0   -   0   0   0   0
SAL  2014-07-04   00h 59m   1   0   0   1   0   -   0   0   0   0
SAL  2014-07-03   04h 28m   6   5   0   0   0   -   1   0   0   0
SAL  2014-07-02   08h 26m   5   2   1   1   0   0   0   0   1   -
SAL  2014-07-01   08h 25m   14  8   0   4   0   0   0   0   2   -

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PPS - Phi Piscids
SSS - Southern Sigma Sagittariids
SCA - Sigma Capricornids
DPI - Delta Piscids
JBO - June Bootids
CAN - c Andromedids
CAP - Alpha Capricornids
MIC - Microscopiids
JPE - July Pegasids

June 24-30 Meteors

This post brings us through the end of June. Even though meteor rates are relatively low and the nights are short, June is a good time to observe in Tucson thanks to the lack of clouds and dry air. By the first week of July (perhaps as early as today 7/2) the monsoon kicks in and clouds, t-storms and high humidity rule the nights.

We are also starting to see the start of some of the showers that make July so interesting. The Alpha Capricornids (CAP) are the first to start. This shower is produced by the weakly active comet 169P/NEAT (the image below is from the Vatican VATT 1.8-m taken earlier this year after 169P’s most recent perihelion passage). This comet has a similar orbit to two other comets, 141P/Machholz and P/2003 T12 (SOHO), suggesting that all three are pieces of a larger comet. In fact, when 141P was discovered in 1994 it was in the process of splitting. A cascading series of splitting seems to be a common process for comets and might even be an end-state for many of them.

169P_2014Mar31_CarlHergenrother

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Obs  Date(UT)      Time    TOT SPO ANT PPS SSS SCA DPI JBO CAN CAP MIC
SAL  2014-06-30   08h 11m   14  11  1   0   -   1   -   0   0   0   1
SAL  2014-06-29   08h 21m   23  15  3   2   -   1   -   0   1   1   -
SAL  2014-06-28   08h 16m   11  7   2   0   -   0   -   1   1   0   -
SAL  2014-06-27   07h 18m   15  6   1   3   -   2   -   1   0   2   -
SAL  2014-06-26   08h 24m   17  13  0   0   1   0   0   0   2   1   -
SAL  2014-06-25   08h 24m   15  10  2   0   0   1   0   0   0   2   -
SAL  2014-06-24   08h 23m   15  10  2   1   0   0   1   0   1   -   -

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
PPS - Phi Piscids
SSS - Southern Sigma Sagittariids
SCA - Sigma Capricornids
DPI - Delta Piscids
JBO - June Bootids
CAN - c Andromedids
CAP - Alpha Capricornids
MIC - Microscopiids

June 16-23 Meteors

My camera system was not active between the nights of June 7 and 15. I was on vacation and decided not to leave the system on. The Metrec software does have the ability to operate automatically for nights on end but lately the old Windows XP machine that runs the software has been acting a little flaky so I gave the system a rest.

The year can be split into two meteor seasons. A period of many active productive showers and lots of sporadic meteors spans from July to early January. The other half of the year, from mid-January through June, sees few productive showers and few background meteors. With the expceptions of the Lyrids of April and the Eta Aquariids of early May, there are no major showers during this period and even these two are among the weaker major showers (though both have produced larger rates from time to time).

The middle of June is still within the weaker meteor season, something I sometimes refer to as the ‘meteor doldrums‘. The most active showers were the Phi Piscids  (a recently recognized shower from a unknown retrograde long-period comet) and showers near the Antihelion region (material on prograde short-period orbits).

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Obs  Date(UT)      Time    TOT SPO ANT NZC PPS SSS SCA DPI JBO
SAL  2014-06-23   08h 11m   11  7   3   -   0   0   1   0   0
SAL  2014-06-22   08h 06m   19  13  2   -   2   1   1   0   0
SAL  2014-06-21   08h 16m   12  7   1   -   3   0   0   1   -
SAL  2014-06-20   08h 16m   12  9   2   -   1   0   0   -   -
SAL  2014-06-19   08h 23m   17  14  2   -   0   0   1   -   -
SAL  2014-06-18   08h 21m   11  8   2   -   1   0   -   -   -
SAL  2014-06-17   07h 09m   11  6   4   0   1   0   -   -   -
SAL  2014-06-16   08h 18m   12  8   0   0   2   0   -   -   -

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
NZC - Northern June Aquilids
PPS - Phi Piscids
SSS - Southern Sigma Sagittariids
SCA - Sigma Capricornids
DPI - Delta Piscids
JBO - June Bootids

Early June Meteors

The first week of June continued the level of activity from the end of May. I didn’t collect any data between the nights of June 7 and 15 as I was on vacation with my family. Results after June 16 will be presented in a future post.

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Obs  Date(UT)      Time    TOT SPO ANT SOP CAM NSC JMC NSA ARI
SAL  2014-06-06   08h 29m   15  10  2   3   -   -   -   -   0
SAL  2014-06-05   07h 51m   12  9   2   1   -   -   0   0   0
SAL  2014-06-04   08h 31m   13  12  1   0   -   -   0   0   -
SAL  2014-06-03   08h 29m   17  11  2   1   -   1   1   1   -
SAL  2014-06-02   08h 18m   11  8   1   2   -   0   0   0   -
SAL  2014-06-01   08h 09m   11  11  0   0   0   0   0   -   -

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
ETA - Eta Aquariids
SOP - Southern May Ophiuchids
CAM - Camelopardalids
NSC - Northern Omega Scorpiids
JMC - June Mu Cassiopeiids
NSA - Northern Mu Sagittarids
ARI - Arietids

Late May Meteors

The story of the last week or so of May was the Camelopardalids (CAM). As mentioned in my last two posts, the CAMs had the potential to produce a very nice visual meteor display. Unfortunately, rates were much lower than expected and visual observers only counted a handful per hour on the peak night of May 23/24.

My video camera only picked up 4 CAMs on the peak night showing just how much of a let down the CAMs were. Other than the CAMs, the only other shower that showed much activity was the Southern May Ophiuchids (SOP).

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Obs  Date(UT)      Time    TOT SPO ANT ETA SOP CCA CAM NSC JMC
SAL  2014-05-31   07h 17m   11  10  0   -   1   -   0   0   0
SAL  2014-05-30   08h 26m   13  13  0   -   0   -   0   0   0
SAL  2014-05-29   00m 00m         --- BAD WEATHER --- 
SAL  2014-05-28   06h 33m   12  10  2   0   0   -   0   0   -
SAL  2014-05-27   08h 28m   10  5   2   0   2   -   1   0   -
SAL  2014-05-26   07h 45m   10  8   1   0   1   -   0   -   -
SAL  2014-05-25   03h 42m   4   2   2   0   0   -   0   -   -
SAL  2014-05-24   08h 42m   15  11  0   0   0   -   4   -   -
SAL  2014-05-23   07h 38m   5   4   0   0   0   -   1   -   -
SAL  2014-05-22   00h 00m          --- LOST DATA ---
SAL  2014-05-21   07h 57m   8   7   0   1   0   0   0   -   -
SAL  2014-05-20   08h 33m   6   4   0   0   0   1   1   -   -

SAL - SALSA3 camera in Tucson (Carl Hergenrother)
VIS - Visual observations from Tucson (Carl Hergenrother)
Time - Total amount of time each camera looked for meteors
TOT - Total number of meteors detected
SPO - Sporadics (meteors not affiliated with any particular meteor shower)
ANT - Antihelions
ETA - Eta Aquariids
SOP - Southern May Ophiuchids
CCA - Chi Capricornids
CAM - Camelopardalids
NSC - Northern Omega Scorpiids
JMC - June Mu Cassiopeiids

Camelopardalid “No-show”?

Camelopardalids… more like the Camelopardaliduds or the Camelordalididn’ts.

Last weekend’s much anticipated Camelopardalid meteor shower from comet 209P/LINEAR was a big disappointment for most meteor watchers. Rather than ZHRs of 100-400, the peak ZHR only reached ~15 per hour. Making things even worse, the ZHR rate is not the rate of actual visible meteors (ZHR is meant for comparing different showers under different observing conditions; ZHR is an idealized rate only valid for observers under very dark skies and with the radiant overhead). Still a Camelopardalid ZHR of 100-400 should have produced 15-60 meteors per hour for the average observer. The actual ZHR of 15 means that most people saw a couple of Camelopardalids per hour at most.

Before going into what went wrong, let’s look at what we got right.

Comet 209P/LINEAR does produce meteors and, in particular, laid down a number of dust trails that caused a meteor outburst. In fact, the predicted time of for crossing the dust trails appears to have been spot on.

What went wrong? Obviously our understanding of the properties of the dust of 209P and perhaps even their exact location in space was wrong. The dust the Earth encountered was smaller than expected. Combine that with slow encounter velocities (19 km/s) and you get a shower that produced meteors that were too faint to be seen visually. Meteor radar observatories such as the Canadian Meteor Orbit Radar and the Japanese Radio Meteor Observatory saw many more meteors in the 6th to 7th magnitude range.

In short, the biggest problem was that we were going into this shower blind. For a few years around 2000, very accurate predictions of the Leonids were made. But these predictions had the benefit of centuries of positive (and negative) observations to better quantify the number of meteors that could be seen. The Camelopardalids had no ‘back catalog’ of meteor outbursts. Not only were no outbursts observed prior to this year but the parent comet was only discovered in 2004. So we had no knowledge of how active, or even if the comet was active at all, prior to discovery.

For the people who study meteor showers and their parent comets, the shower (dud or not) was a learning experience and the data we collected is still very useful. 209P is making a very close approach to Earth (~0.06 AU tonight) and it is almost unprecedented that we can observe such a low-activity comet this close.

For more analysis and some early results on the shower, check out the pages by Peter Jenniskens and Sky and Telescope.

 

209P/LINEAR and this weekend’s Camelopardalids

This Friday evening/Saturday morning meteor watchers in Canada, the United States and Latin America may be treated to a meteor outburst from a rarely seen meteor shower. There is a possibility that dust from short-period comet 209P/LINEAR will produce a nice meteor shower.

There has been plenty already written on this possible shower, so I’ll just list a few sites that you should definitely visit.

American Meteor Society – where, when and how to observe the shower

Peter Jenniskens Meteor blog – the latest on what we know about the shower and its parent comet

International Meteor Organization – up-to-date activity graphs

The parent comet, 209P/LINEAR, is making a close approach to Earth this month. In fact at a little over 0.05 AU from Earth, 209P will be making the 9th closest known approach of a comet to Earth. Unfortunately it is very low activity comet and only observers with very large backyard telescopes will be able to see it. The movie below was made by myself only a few days after the comet’s perihelion.

Comet 209P/LINEAR as seen with the Vatican VATT 1.8-m telescope on 2014 May 9 UT in images by Carl Hergenrother.

 

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