Jan 13/14 Meteors

The relatively low levels of meteor activity that we’ve seen over the past week continues. This is due to a bright Moon during most of the night and low background meteor rates during January.

From Bob’s notes: “Rates were slightly less tonight as no Coma Berenicids were recorded. There was one sporadic fireball caught near the Big Dipper and a long “Earthgrazer” that crossed the entire field of view.”

Obs  Date (UT)   TotTime TOT SPO ANT COM
TUS  2009-01-14  12h 00m  12  12  0   0
SDG  2009-01-14  11h 52m  28  25  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)
ANT – Antihelions
COM - Coma Berenicids

Jan 12/13 Meteors

From Bob’s notes: “Rates were much the same as the previous night. There was an increase in activity from the Coma Berenicids offset by slightly lower sporadic rates.”

In Tucson, the rates were exactly the same as the previous night.

Obs  Date (UT)   TotTime TOT SPO ANT COM
TUS  2009-01-13  12h 02m  14  13  0   1
SDG  2009-01-13  09h 30m  32  22  4   6

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)
ANT – Antihelions
COM - Coma Berenicids

Jan 11/12 Meteors

From Bob’s notes: “Rates were a little better tonight including some bright meteors, not quite reaching fireball category of magnitude -5.”

Obs  Date (UT)   TotTime TOT SPO ANT COM
TUS  2009-01-12  12h 02m  14  13  0   1
SDG  2009-01-12  10h 08m  34  29  4   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)
ANT – Antihelions
COM - Coma Berenicids

Jan 10/11 Meteors

The Full Moon continues to make meteor observing difficult. With only 7 meteors detected during the entire night, last night was the lowest tally for an entire clear night since early June. Conditions should improve in a few days as the moon decreases in brightness and also moves south and out of the field of view of my camera.

From Bob’s notes: “The full moon continues to obscure the fainter activity resulting in rates of only 1/2 of normal for this time of year.”

Obs  Date (UT)   TotTime TOT SPO ANT COM
TUS  2009-01-11  12h 03m  7   7   0   0
SDG  2009-01-11  11h 55m  28  22  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)
ANT – Antihelions
COM - Coma Berenicids

Jan 7/8/9/10 Meteors and a Big Full Moon

This weekend’s Full Moon will be the biggest and one of the brightest of 2009. This is caused by the Moon’s orbit which is not a perfect circle. This month, the Moon will be closest to the Earth (what we call perigee) today at a distance of 214,500 miles  (357,500 km). At its furthest (called apogee) on Jan 23 UT, the Moon will be 243,669 miles (406,115 km) away. That’s a difference of 29,169 miles (48,615 km) or ~14%. Due to the way the Moon’s orbit is lined up, Full Moons in December and January are the largest while the ones in June and July are the smallest. Also the Full Moons in December and January travel the highest in the sky for observers in the Northern Hemisphere. For more on this month’s large Full Moon, see this Science@NASA article.

The Full Moon means that it is real hard to observe meteors right now. Still the Tucson based SALSA camera system is still picking up 12-20 meteors per night. Most are Sporadics not affiliated with any particular shower, though a few Antihelions and Coma Berenicids can also be seen.

From Bob’s notes on Jan 7/8: “The weather here cannot make up its mind whether to be good or bad. Every other night seems clear recently. As for the meteor rates, they were downright pitiful on the morning of the 8th. Although the moon was bright, a total of 27 is far below expectations for my system, even in January.”

Obs  Date (UT)   TotTime TOT SPO ANT COM
TUS  2009-01-10  11h 00m  17  15  0   2
SDG  2009-01-10  10h 57m  28  24  2   2
TUS  2009-01-09  11h 38m  13  12  1   0
TUS  2009-01-08  12h 05m  18  17  0   1
SDG  2009-01-08  11h 55m  27  24  2   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)
ANT – Antihelions
COM - Coma Berenicids

Jan 5/6/7 Meteors

Meteors rates have settled down after the Quadrantid peak. Almost all of the activity has been taking place after midnight though this is partly due to the Moon which is high and bright in the evening.

From Bob’s notes: “I lost the 6th to a mix of high and low clouds. I can tolerate high clouds but low clouds often create thousands of false detections which is difficult to sort. This morning was mostly clear with only thin cirrus present at times. As Carl mentioned in his most recent installment, the moon is preventing us from detecting any faint meteors.”

Obs  Date (UT)   TotTime TOT SPO ANT COM
TUS  2009-01-07  11h 22m  16  14  1   1
SDG  2009-01-07  05h 50m  40  34  2   4
TUS  2009-01-06  03h 02m  10  9   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)
ANT – Antihelions
COM - Coma Berenicids

Jan 4/5 Meteors

Though it rained all night in Tucson, the weather was fine in San Diego and Bob was able to get a good night of video observing in. What a difference 2 nights make. The number of Quadrantids plummeted to only 2 out of a total of 51 detected meteors.

From Bob Lunsford’s notes: “The skies have finally cleared allowing me to again monitor the skies. There is not much left of the Quadrantid shower, which provide such as splendid display on the morning of the 3rd. The Antihelion radiant was also strangely quite this morning, when one would expect at least a meteor per hour from this radiant during the morning hours.”

Obs  Date (UT)   TotTime TOT SPO ANT COM QUA
SDG  2009-01-05  11h 22m  51  46  0   3   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)
ANT – Antihelions
COM - Coma Berenicids
QUA - Quadrantids

More on the Quadrantids

Another winter storm has been moving through Arizona. As a result the past two nights have seen nothing but clouds and rain. Hopefully the meteor watch can continue again tonight.

Observations of the Quadrantids continue to be reported to the International Meteor Organization from all over the world. The plot seen below shows the geographic location of visual observers who have submitted their reports. By visual, we mean observers who only used their eyes, and not cameras, to count meteors.

quad_2008_map1

Geographic distribution of Quadrantid visual reports to the International Meteor Organization (IMO). Plot from the IMO's "Quadrantids 2009" page at http://www.imo.net/live/quadrantids2009/.

This map is interesting because it tells us a lot about the state of meteor astronomy and amateur astronomy. The furthest southern observer was in Venezuela. This is due to the fact that  the Quadrantids radiate from a northern Declination of +49 degrees. This means that the Quadrantid radiant is located directly above a latitude of +49 degrees. The further south one gets the harder it is to see the Quadrantids. In  fact, they are very hard to see south of 10 degrees South and invisible south of 40 degrees South.

Due to the short duration of the Quadrantids and the frigid temperatures in the Northern Hemisphere during early January, the number of people observing the Quadrantids is much lower than the Perseids in mid-August. The majority of observers are located in Europe and North America with a few observers in Japan and the rest of Asia. The most extreme observers was Bruce McCurdy who observed from Yellowknife in the Northwest Territory of Canada. Temperatures were below -40 C (-40 F) and he was able to keep warm by observing through the open moon-roof a running and heated vehicle.

Plots of the Zenithal Hourly Rate show just how sharp the peak was. The first plot shows a period of more than a week while the second plot covers a single day centered on the peak. It is apparent that the Quadrantids produced very low rates (ZHR < 5-10) except for a period of just over 24 hours. In Europe, rates were rapidly climbing from ~30 to ~110 meteors per hour. (Again note that these rates are only valid for dark skies and when the radiant is overhead. In many locations the actual number of observable meteor was less.) The peak occurred over all of North America with a peak ZHR of ~160. Observers in Asia were able to catch the downward leg of the peak as rates dropped from ~120 to ~50. By the next night in North America, rates were only around 10 per hour.

quad_2008_zhr1

ZHR plot of Quadrantid activity for a week or more before and after the peak. Plot from the IMO's "Quadrantids 2009" page at http://www.imo.net/live/quadrantids2009/.

quad_2008_zhr_peak1

ZHR plot of Quadrantid activity centered on the night of peak activity. Plot from the IMO's "Quadrantids 2009" page at http://www.imo.net/live/quadrantids2009/.

With a peak ZHR of ~160, this year’s Quadrantids were as good as they can be. From year to year, the peak rates can vary from ZHRs of 80 to 160.

We now enter a slow season for meteor observing. Rates of sporadic meteors drop to only a half dozen or so per hour and the next major shower isn’t till late April.

Jan 2/3 Meteors and a Great Quadrantid Display

The Quadrantids put on a great show last night. With 107 meteors detected, my camera broke its previous nightly record of 80 meteors. At least 73 of the meteors were Quadrantids and I suspect that some of the Sporadics were actually Quadrantids that were mis-identified by the software.

I also went outside and observed the shower the old fashioned way, by bundling up and sitting outside. I set my alarm for 4:00 am. This was followed with my usual dawdling about whether I really want to get up and go outside. Luckily I didn’t fall back to sleep and was outside and ready to go at 4:30 am. It didn’t take long to realize that the Quadrantids were putting on quite a show with 8 QUAs seen in the 1st 7 minutes.

In total I was able to detect 97 meteors (82 were Quadrantids) in 01h 50m of observing. The limiting magnitude (faintest stars that could be seen) was +5.5. If you lived in a dark rural site, you would have seen many more meteors (perhaps 3 times as many). Brighter urban sites would only have seen the handful of brighter ones.

Observations are still filtering in to the International Meteor Organization. According to their “live” plot of Quadrantid activity, the shower may have been peaking over western North America. In Europe, observers recorded rapidly increasing rates that were already approaching a Zenithal Hourly Rate (ZHR) of 100. ZHR is how many meteors you would see if you lived under dark skies (limiting mag +6.5) and the radiant was overhead. Rates over North America appear to have been in the 125-200 per hour range. These rates are twice as high as expected. The 2009 Quadrantids were definitely one of the better displays of the past few years.

Due to the short, sharp nature of the Quadrantid peak (rates were only at ZHR = ~10-20 24 hours ago) the best is over. A few Quadrantids per hour will be visible per hour tomorrow night.

Below is a movie of all 107 meteors detected by the SALSA camera over Tucson last night. All of the action occurred between 11:30 pm and 6:30 am local time.

qu5

Obs  Date (UT)   TotTime TOT SPO ANT COM QUA
TUS  2009-01-03  12h 07m 107  32  0   2   73

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)
ANT – Antihelions
COM - Coma Berenicids
QUA - Quadrantids

Jan 1/2 Meteors and the Quadrantids

Last night was almost a exact copy of the previous night with a similar number of meteors being detected.

Tonight marks the peak of the Quadrantid meteor shower. Unlike most major showers that have broad peaks which cover many nights, the Quadrantids have a sharp peak that only lasts a few hours. As a result, whether you see a few Quadrantids a night or a few Quadrantids an hour depends on whether you catch the peak.

This year there are 2 predictions for the peak. Based on past Quadrantid peaks, the International Meteor Organization predicts a peak on January 3 at 12h 50m UT. That’s 5:50 am MST or 4:50 am PST. If this prediction is correct, the Quadrantids will be best over western North America and probably pretty good for all of North America. You can also monitor the activity level of the QUAs at the IMO’s ZHR Live site.

A second prediction is based on work by Jeremie Veubaillon and published in a chart in Peter Jenniskens’s book “Meteor Showers and Their Parent Comets”. It predicts an earlier peak on January 3 at ~1:00 UT. That’s in the early evening for North America at a time when the shower will not be easily visible. The Veubaillon prediction is based on all of the Quadrantids having been released during the break-up of a comet in 1490.

If you live in a reasonably dark place in North America and can brave the cold, wake up 2 hours before sunrise. You should be able to spot a dozen or more Quadrantids per hour.

Obs  Date (UT)   TotTime TOT SPO ANT COM QUA
TUS  2009-01-02  12h 08m  28  19  2   3   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)
ANT – Antihelions
COM - Coma Berenicids
QUA - Quadrantids

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