Radiant Determination from Radio-Meteor Observation

Under normal circumstances radio-meteor observers are limited to counting the number of meteor reflections recorded in a given interval. But, under exceptional circumstances we may also be able to derive the meteor's location and direction of travel. To achieve this, we need several observers to record the meteor's head-echo simultaneously.

On August 17th, 2008 at approx. 01:44 UT several observers in Belgium were tuned the frequency of the VVS beacon located at AstroLab near Ypres in western Belgium. Several of the observers recorded a meteor reflection including a head echo. Below is a compressed image showing the results at six locations. The x-axis has a duration of 2 seconds in each case.

Using the method described by Richardson and Kuneth[*], and further developed by Christian Steyaert, we have attempted to determine the location of the reflection and the meteors velocity and radiant. The following information is based on the best-fit that we've found to the data so far. We'll be working on the confidence limits next.

The following chart shows a plan view of the approximate path of the meteor. The axes have been rotated to show a normal geographical view (north up and east to the right), all dimensions are in metres; the VVS Beacon is located at the origin (0, 0, 0).

The analysis suggests that the meteor originated from a radiant low in the northwest sky, in the constellation of Hercules. It was traveling at 60 km/sec and penetrated relatively deeply into the atmosphere. The path carried the meteor between the Beacon and the observers.

The chart also shows the location of the specular reflection points (also the point of closest approach), for each observer. As the meteor travels across the sky, it presents a specular reflection in the order: Blondeel, Pellens, Verbellen, Camps and Oeyen. There's approximately 0.14 seconds between the first observer hearing a specular reflection and the last.

If you are any amateur astronomer interested in observing radio meteors, then please get in touch. Those in the south-east of England may be interested in observing using the same Beacon as was used for the observation described above. The Vereniging Voor Sterrenkunde (VVS) beacon is operated by the Flemish Astronomical Association and will easily be detectable across the south and east of England.

I'd like to take this opportunity to thank the members of the VVS, Astrolab IRIS where the beacon is located and BIPT Belgian Institute for Postal services and Telecommunications (BITP), in particular David Erzeel, for the license tooperate the VVS Beacon.

*'Revisiting the Radio Doppler Effect from Forward-scatter Meteor Head Echoes', by James Richardson and Werfried Kuneth [WGN, the Journal of the IMO 26:3 (1998)]