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Orionids 2011

MeteorsPosted by Koen Miskotte Thu, October 27, 2011 16:56:24

Orionids 2011

Picture: Composition of 10 Orionids recorded on 22/23 and 23/24 oktober 2011.

After several years with increased Orionid activity (2006, 2007, 2008, 2009 and 2010 the 2011 return was eagerly awaited. Mikiya Sato, a Japanese meteor researcher, had no increased activity predicted and the expectation was that the Orionids would behave "normally". That means many faint meteors and a ZHR of 20-25.Luckily I had during the period of October 19 to 24 a number of clear nights. I observed from the Groevenbeekse Heide, a moor near Ermelo.

In the early morning hours of October 20th the weather cleared already, but because the spells arrived rather late in Ermelo, I had to leave to work. The night of 21/22 October was completely clear. There were some clouds in western direction, but after some time they disappeared in western direction. Occasionally some thin cirrus clouds passed, so the limiting magnitude was a bit low: about 6,3. Despite of that good numbers of meteors were seen. I could observe from 22:10 to 01:45 UT. Longer was not possible because I had to work at 3:00 UT and also the climbing moon was a disturbing factor.
Orionid counts rised up to 10 per period (t.eff. 0.70 hours, 6.0 lm). The Taurids were quite active with hourly counts up to 6. An excellent Orionid with two flares of -2 and 5 seconds train was seen at UT 23:33:45 UT in the constellation of Taurus. Also a number of Orionids of magnitude 0 and +1 were seen, all showing relatively long lasting trains.
I observed during a total of 3,60 hours into the night. I saw 29 ORI, 7 STA, 6 NTA, 5 EGE, 1 LMI and 26 SPO. So it is a total of 73 meteors.

The night 22/23 October was also clear. This night I planned a long meteor session. My Canon EOS 40D went along with the Canon EF 15 mm F 2.8 fish-eye lens. This setup was powered by a Meade accu and a Astronomiser suply unit. Advantage of this is that the camera run all night undisturbed (no need to changing the BP511 batteries). I also used the 12V power for a dew-zapper. Once camera was set, I could concentrate on observing the meteors.
I could observe between 23:00 and 4:12 UT. The air was much cleaner than last night and only occasionally an airplane contrail moved through my field of view. Limiting magnitude up to 6.45. There was a average wind blowing from southeastern direction with a temperature of 2,5 degrees Celcius.
The Orionids were clearly present, the hourly counts rose from 7 to 23 in the last hour (Lm 6.0). The best Orionids were a magnitude -1 and three of magnitude 0. The Taurids were less active than yesterday. In total I saw during 5,13 hours effective observing time 70 ORI, 5 STA, 7 NTA, 5 EGE, 1 LMI and 41 SPO. A total of 129 meteors, which is very good. The camera also scored well with 11 meteors, including the finest a -1 Orionid.

Picture: Orionid of magnitude -2 on 24 oktober 2011 at 01:44:35 UT. Click on this photo to see the persistent train drifting.

The night October 23/24 was also clear. This night a stronger wind was blowing, but temperature was a bit higher than the previous night. I started early in the evening between 18:00 and 19:00 UT. In that period I captured the comet C/2009 P1 Garradd with my Astrotrac Travel Mount, a Canon EOS 40D and EF 200 mm F 2.8 lens. Then, after a few hours sleep at home, I returned to the moor for a few hours meteor observing.
Between 23:53 and 04:16 UT I could observe under good sky conditions. Same camera setup was used as in the previous night. The sky was even a bit better than yesterday with a limiting magnitude of 6.5 in the zenit! The Orionids were much less active with hourly counts of around 13/14. A beautiful Orionid of magnitude -2 was seen at 01:44:35 UT with a few seconds afterglow in the constellation of Eridanus. The meteor was also beautifully captured by the 15 mm fish-eye and on the next five shots is the drifting train still visible.
I saw a during 4,33 hours of effective observing time 45 ORI, 4 STA, 3 NTA, 3 EGE, 2 LMI and 41 SPO. The camera recorded 11 meteors again.

The picture below is a composition of the 10 most beautiful meteors photographed in the nights 22/23 and 23/24 October 2011. The camera made pictures of 29 seconds at 1000 ISO and f 3.2.

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