Between 1981 and 1985, hundreds of strange lights have appeared in a small valley in central Norway. Named after the valley, the lights have been named: The Hessdalen Phenomenon. A research station was set up in the valley in 1983. During January-February 1984, eight different kinds of instruments were in use, with the following results:
Camera with grating : Three pictures showed a continuous spectrum. No spectral lines were seen on any picture.
IR-viewer: This instrument was used too little to drawn any conclu sion.
Spectrum-analyzer: Sometimes there were electromagnetic signals with harmonics of about 80 MHz.
Seismograph : No local seismographic activity was measured.
Magnetograph : The magnetic field did sometimes change when the lights showed up. There also seemed to be a correlation with the mag netic pulsation.
Radar : The lights could be seen on radar. The speed varied all the way from 0 to 30,000 km/hour. Sometimes the radar saw something moving at a low speed, but no lights were seen by eye. Clearly, there was something there, but only the radar showed it.
Laser : A laser-beam was directed toward the light, and the behavior of the light changed.
Geiger-counter : No radioactive radi ation was detected. But the source was 1 km away when this instrument was used.
(Strand, Erling; "Project Hessdalen -- A Field Investigation of an Unknown Atmospheric Light Phenomenon," Journal of Scientific Exploration, 8:581, 1994.)