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Leonids 2000: ESA observation reports

Looking at the Leonids
Introduction Detlef Koschny is hoping to obtain three sets of simultaneous video observations on the nights of 16-17 and 17-18 November. While Koschny's cameras will be located in the Harz Mountains of Germany, his colleague Joe Zender will be duplicating the observations in the north of the Netherlands. A group of Dutch amateur meteor observers will also be assisting by making their own observations from a third site.
More about this research

18-Nov-2000 19.50 UT from Joe Zender Here is a short report of our campaign from the 'Werkgroep Meteoren' and ESA/SSD.

On the night of 16 to 17 November, only two stations succeeded in observing simultaneously: Henry Henriks (Werkgroep Meteoren) located at the Heest Observatory and Joost Haartman, Michiel Brentjens and Roy Keeris (Werkgroep Meteoren) located near Almere at the Groene Kathedraal, were able to observe with the image intensified video camera systems for about 4 hours. The camera systems are identical and later analysis will provide information on meteor rates and orbit parameters. The activity for this night was moderate and no dedicated peaks or events can be reported.

Andre Knoefel (IMO) located near Essen as well as myself, Mark Neyts and Anne van Weerden (both of Werkgroep Meteoren) had a cloudy night and the minutes of open skies just allowed us to calibrate and test the camera system for a few minutes.

On the night of 17 to 18 November, the situation for the teams changed and Andre Knoefel was clouded out for the whole night whilst the team around Joost Haartman in Almere had rain until 01.00 UT. They then decided to go east near the German border, but reported rain and clouds at 06.00 UT this morning.

The team in Hoogersmilde did observe under good conditions until 00.15 UT when clouds came in and it started raining. We dismantled the equipment and waited for a sign from Jacob Kuiper (KNMI) who reported at 03.00 UT that we could have a chance of a cloudless area near Groningen. We sped up to Groningen, found a viewing location and installed the camera equipment at 03.20 UT, about 20 minutes before the predicted peak. We did indeed observed increasing activity, but due to the weather conditions (clouds and moon) it would not be sensible to give meteor rates here. Just to give you an idea, I observed about 30 meteors in this first hour. He all had the impression that the amount of bright meteors against the weak ones was high. The activity decreased and a rain shower forced us to pack all the equipment back into the car. At about 04:45 UT we noticed increased activity and decided to install the equipment again and went on with visual and camera observations until 06.30UT. Dawn forced us to shutdown the intensified camera system but we believed to have seen an increasing activity before dawn (from 05.30 UT to 06.15 UT).

Simultaneous observations were not possible on the second night (17-18) due to the continually changing location of the teams. We hope that the analysis of the videotapes will give us a better idea of the ZHR values.

Many thanks to the teams from the Werkgroep Meteoren and Andre Knoefel for their efforts.

18-Nov-2000 09.50 UT from Detlef Koschny I left Lindau yesterday evening at around 18h in search of clear skies. Going west, I passed a few areas with clear skies. But the clouds always moved in quickly. I decided to head for the coast in the Netherlands, often the weather is different close to the sea. And indeed it was - thunderstorms and rainshowers! At around 3h in the morning the rain had stopped but it was still cloudy, so went to sleep... Just hope that my colleagues were luckier.

17-Nov-2000 12.40 UT from Detlef Koschny Bad luck so far. I am still at the Max-Planck-Institute in Lindau/Harz. I went outside last night at around 02:00 in the morning. The moon illuminated nicely some high thin clouds. Some stars were visible, but it was not very nice... Spent 30 minutes under the sky and saw two sporadic meteors, but nothing spectacular.

Now it is raining and the weather forecast is bad. Will try to find a better place for tonight!

Further details (16-Nov-2000) This year's campaign is to be carried out together with the 'Werkgroep Meteoren', a Dutch meteor working group. We intend to observe during the nights of 16 to 17 November and from 17 to 18 November. We will observe from four different locations, separated by 70 km to 100 km which will allow parallel observations with our camera equipment.

The set-up for the four locations is as follows:

  • Hoogersmilde
    Team: Mark Neyts, Anne van Weerden, Joe Zender
    Location: lat: + 52 55 31.9 +/- 0.7" ; lon: - 6 23 48.2 +/- 1.1" (N52.9253, E6.396)
  • Groene Cathedraal, Almere
    Team: M.A.Brentjens, Roy Keeris, Joost Haartman
    Location: lat: + 52 19 29.8 +/- 0.6" ; lon: - 5 19 7.3 +/- 1.1" (N52.324944, E5.31869)
  • Sterrewacht Heest
    Team: Henry Hendriks
    Location: lat: + 51 42 15.5 +/- 0.6" ; lon: - 5 29 16.7 +/- 1" (N51.704305, E 5.48797)
  • Essen, Germany
    Team: Andre Knoefel
    Location: lat: 51 23 41 ; lon -6 58 46 (N51.39472, E 6.9794)

A second observation station in Germany will be manned by Detlef Koschny and Udo Telljohann, the precise location is as yet unknown.

Each of the observation stations will be equiped with an image-intensified video camera.

Listening to the Leonids
Introduction Jean-Pierre Lebreton and Trevor Sanderson from ESA's Space Science Department at ESTEC will be using radio signals rather than telescopes or cameras to observe the elusive meteors. Their technique uses the ability of plasma (ionised gas) clouds around glowing meteor trails to reflect radio waves. More about this research

Read the press release from Merlin Communications Merlin supports European Space Agency radio experiment

23-Nov-2000 - Report from Jean-Pierre Lebreton We have started to summarize the HF radio observations. Below are plots for two selected time slots: 04:39 to 04:46 (Local time) and 08:55 to 09:10 (Local time) for 7 days (nights) around the Leonid shower (from 14 to 20 November). During the night timeslice, it is clear that the (non-sporadic) activity has increased significantly on 18 November, but it seems there was some activity 1-2 days before (16 and 17 November), and perhaps 1 day after (19 November).

Left: Trace for 14 to 20 November, 04:39 to 04:46 local time
Right: Trace for 14 to 19 November, 08:55 to 09:10 local time
(Click on image to enlarge)

The day timeslice is quite interesting as well. First note that the change of transmitter from Cyprus to Woofferton is very clear. Not many echoes were obtained when listening to the Cyprus transmitter. On 18 November the activity at around 09:00 was much higher than the days before or after. Some activity was also "audible" on 17 November. Note the timeslice for 20 November is not yet available.

We also managed to make a video, using a standard CCD digital camera, showing a meteor with the Moon in the background. It's not a spectacular one compared to good video movies that I have seen, but the Moon in the background doesn't help. This was a pretty bright meteor. You may also see clouds moving over the Moon. We did not have a perfectly clear sky, but it was sufficient to enjoy the show. Watch the video

20-Nov-2000 - Report from Jean-Pierre Lebreton Pretty good show during the night of Friday to Saturday. On Friday Udo, Olivier, Hakan and myself gathered at ESTEC for a good part of the night.

We had good sky from about 02:00 onwards, while it was pouring rain until 01:30! We saw a good number of meteors from ESTEC's parking lot. We especially enjoyed lasting trails for a few seconds despite the bright moon... and patchy clouds. This was quite impressive. The radio recordings are excellent. There are plenty of very unusual echoes which can be attributed to the Leonids. The BBC transmitted from Woofferton for us until 05:00 UTC. They then switched to their nominal transmission schedule afterwards (from Cyprus between 05:00 UTC and 07:00 UTC and then from Woofferton and Skelton from 07:00 UTC onwards). We saw an increased activity between 03:00 and 05:00 UTC, and also from 07:00 UTC onwards. We could not detect echoes during the transmission from Cyprus as the geometry was not adequate.

We even managed to make a video (with a pretty standard CCD camera) and grabbed a few meteors on a bright Moon background. Mpeg files are being prepared.

Two samples of our radio recordings are shown below. They represent spectograms in a 25 Hz band around 1 kHz. Low frequency are on top and higher frequencies are on the bottom of the plot.

04:57 to 05:22 local time, 18 November

07:56 to 08:19 local time, 18 November

More images and sound files are available on the Solar System website

17-Nov-2000 - During the night of 13 November, sound recordings were made of the Leonids - click here for the .wav sound file

Output after analysis with COAA software

Output from the .wav sound file was analysed using advanced signal processing software provided by the COAA observatory in southern Portugal, and gave the above trace.

More images and sound files are available on the Solar System website

16-Nov-2000 - ESA Scientists have started listening to the Leonids. By tuning into the radio signals some recordings have already been made prior to the anticipated peaks in activity later in the week.

The image below shows the spectogram obtained during the night of 15 to 16 November for the time period 04:00 to 04:25 LT (-1 for UTC) which is near the time of the expected peak on the 18 Nov. (03:44 UTC).

On occasion the spectogram shows a spectacular echo, the trace below was obtained during the night of 14 to 15 November between 04:52 and 05:04 LT (-1 for UTC)

Note the spectrograms represent the time variation of the audio output of the receiver. The vertical scale shows frequency. It covers +/-12.5 Hz around the 1kHz central frequency. Higher frequencies are at the bottom of the figure, lower frequencies at the top.

For a full explanation, read more about this observation method

Tell-tale flashes on the Moon
Introduction Håkan Svedhem and a colleague from ESTEC's Space Science Department will be using a 25 cm telescope to observe the dark hemisphere of the Moon on the nights of 16-17 and 17-18 November, during next week's Leonid shower. More about this research

17-Nov-2000 - Håkan Svedhem reports from ESTEC in Noordwijk I had put up the 25 cm with a video camera between the stores building and the transport office barrack to capture eventual impacts on the dark part of the moon. The moon is now fairly close to the radiant and therefore most impacts will occur on the far side. Only a very small part at the northern cusp was exposed to the stream.

The weather was quite good, considering all the rain in the evening. I did however get problems with condensation on the lens around 06:00 and onwards since the humidity increased strongly at that time. I stopped at about 6:40. That was unfortunate since the moon passed the 1932 stream only four earth radii from its maximum just at that time.

I do not yet know if I got any impacts since a flash is only one or two frames typically, and they will have to be searched for by computer which compares consecutive frames. Surprisingly I saw only a few meteors during the whole night, perhaps because the moon was too bright and there were other ESTEC lights on around me (the major street lights and parking lot lights had been switched off).

I will try once more coming night, from about midnight.