Nov 16/17 Meteors and a good Leonid display
November 17, 2009 4 Comments
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