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Hessdalen - Spectrographic records

Spectrographic records

By Erling Strand
Østfold College
Sarpsborg, Norway

Table of contents.

This is the report of the spectrographic records achieved during the Project Hessdalen fieldwork in January and February 1984


What is the Hessdalen Phenomena? What is the physics behind? How does it work? One way to find some answers to such questions is to make measurement on the Hessdalen Phenomena itself and the sorroundings were it shows up. To make measurement on the Hessdalen Phenomena itself you have to be at the right location, with the instruments running, when the Hessdalen Phenomena shows up.

Hessdalen, a small valley in Norway, is a good location for observing Hessdalen Phenomena. Several hundreds of observations have been done in that valley, which is located about 30 km north-west of the town Røros, and 120 km south of Trondheim city. The valley is 15 km long and about 200 people lives there. In the beginning of the 80�es, there were sightnings nearly every day. The main part lasted from December 1981 to the end of 1984. Now, there are in the order of 20 observations each year.
A map of Hessdalen and its surroundings

"Project Hessdalen" was started by people from UFO-Norway, UFO-Sweden and "Föreningen for psykobiofysikk", 3.June 1983. The main topic was to find out more about the Hessdalen Phenomena in Hessdalen. Assistance were received from scientists at the Norwegian Defence research Establishment, the University of Oslo and the University of Bergen. Two periodes of field investigation were run in the valley, in the winter of 1984 and in the winter of 1985. In the order of 40 people participated in those field investigations.

In the first field investigation, which took place in Hessdalen from 21.January to 26.February 1984, the participants were located on four different places in the valley: In a hillside south in Hessdalen, east of the lake Hessjøen. On the southern part of the mountain Finnsåhøgda, west in Hessdalen. In the hillside of the mountain Litlfjellet, north of Hessdalen. There were not people all the time at these locations, but most of the time. Some visual observations were also done from other places in the valley during the fieldwork. The main station was located in the central and northern part of Hessdalen and it was equipped with: An infrared viewer; a spectrum analyser; a seismograph; a magnetometer; a laser; a Geiger counter; a radar; cameras, some fitted with gratting. During the fieldwork, 53 visual observations of an "unknown light" were done, and data were achieved . All written in "Project Hessdalen, final technical report � Part1".

23 spectrographic pictures were shot, using cameras fitted with grating. 5 of those 23 pictures were reference pictures, showing a "known light"; street-light, moon and star. Most of the pictures of the light have too much "spectrographic noise" to get any results. Only three pictures are good enough to find out more about the optical spectra of "the light". These are presented in this paper.

The second field investigation, took place in Hessdalen between 12. January to 28. January 1985. The same type of instruments were used as in 1984, and the participants were located on different places in Hessdalen. No visual observations were done during that periode. This second field investigation continued another 14 days, now without instruments, and only three observers present. One visual observation was done.

Data Acquisition

The spectrographic records were obtained using a diffraction grating in front of a camera. The camera was mounted on a tripod and a cable release was used. When an "unknown light" showed up, a picture was taken, which then shows the "unknown light" and its optical specter.

The cameras were equiped with Kodak TRI-X black and white film. This film has a speed of 400 and a good spectral sensitivity up to 630 nm. Each camera had a lens with a focal length of 50 mm. The gratings used were Paton Hawksley TE.216E, which have 300 lines/mm. The grating was put in front of the lens, as fig.1 shows.

To calculate where the different wavelenght will be found on the film, we can first calculate the angular distribution:



m : the order. m=1 is the first order.
l : The wavelenght of the light.
d : The spacing between adjacent slits in the grating.

When we know the angel q, we can calculate the distance, x on the film:



Prime case

This observation was done the last night of the Project Hessdalen fieldwork, sunday the 26.February 1984 at 3.08 a.m. The location was in the hillside east of the lake Hessjøen, south in Hessdalen. There was no wind and it was minus 10 degree Centigrate. The visibility was good and very close to the ground there was minor fog mist. The strongest stars could be seen.

Map of the location

Bjørn Lagesson, Bjørn Thyselius and Gøran Ohlsson were on location. In the morning, some hours after the observation, Björn Lagesson wrote this:

"We were on location, drinking coffe when Gøran saw a flash of light. About 20 second after that he draw my attention to it. Then did the light show up again and it had an intense brilliance towards us. I run to the cameras and managed to take 3 pictures during the 3 minutes observation time. The first seconds did the light point at us, some seconds afterwards did it point straight down, then did "the spotlight" turn around in a half cirle towards us. I got the impression that it was standing still. The light turned suddenly off."

When the film was developed, there was only two pictures showing the Hessdalen Phenomena. Bjørn Lagesson told then that he was not shure if he took two or three pictures.

Fig 2 - The first picture.

Fig 3 - The second picture.

The three observers told this about the observation:
The light was in the direction towards a mountainside, northwest (azimuth 366 degrees out of 400) of the field-station at the lake Hersjøen. First there was a strong flash, then after about 20 seconds, a strong "spotlight" was pointing at the observers for a couple of seconds. Then the first picture was taken (fig2). After that the "spotlight" was directed straight down for a couple of seconds. Thereafter the direction of the "spotlight" moved upwards and round in a half-circle, and then back to the observers once more. Then the second picture was taken (fig.3). After that did it suddenly "turned off". The time from the first flash to the "turning off", was about 3 minutes. One of the observers thought it might be the spotlight from a snowscooter. He was not sure, because the light seemed to be "too strong for that", and it had a little bit "strange movement". Anyway - this made it only an F5-light, even if it is strange that anyone should be out in the mountains at that time of the day.

The F-scale, used in Project Hessdalen, goes from F1 to F10. It is a systems which tells "how strange" the observation was. Or how likely is it to find a natural explanation. F1 tell that is is 100% sure that it is a known phenomena, for instance a plane or satellite. F10 tell that it is 100% sure that it is not any known phenomena. The border between what should be threated as the Hessdalen Phenomena and a known phenomena is between F4 and F5. That is personal suggestions made by me (Erling Strand) and Leif Havik, who did investigate the reports. If the phenomena get a score of F4, it should not be threated as an unknown phenomena. If it get a score of F5, it should be threated as an unknown phenomena. How important the case is, depends on the score.


Data Analysis.

The prime case used two cameras mounted on the same tripod, with the same type of lens and a common trigger, as fig.4 shows. Then the exposuretime is exatly equal on the two cameraes. One camera had the grating in front and a black and white film, the other had no grating and a color slide 400 ASA film.

Fig 5 - The color picture

Fig 5 shows the color slide, which was taken together with fig.3. It seems that the light has moved during the exposuretime. The distance on the film from bottom to top of the light is 1.25 mm. With a 50 mm lens it gives an angel q of:

q = Arctan(1.25/50) = 1.432 degree.

If this should have been the light from a spotlight on a snowscooter, as one of the witness indicated, it must have been on the mountain. The distance to the mountain is more than 3.5 km. Then the movement x is more than:

x = 3500 · (1,25/50) = 87 m.

That is a too large movement to be done by any snowscooter or any person on that mountain.

The pictures in fig.3 have been to Ground Saucer Watch for analysis. Fig 6 shows the color contour, fig 7 shows the edge enhancement and fig 8 shows the filtering. In fig 7, just above the main part of the light, where the light is moving, it looks like there is two lights close together.

The spectral analysis shows a continuous optical specter from 430 nm to 710 nm. The film used, Tri-X, do not go any higher in optical wavelength. The sudden stop in the light at the long wavelength is due to the spectral sensitivity of the film used.

Go to the spectral analysis

Fig 9 shows one of the reference pictures. This picture is turned 90° anticlockwise, so that the optical specter is seen in the same direction as in fig 2 and 3. The picture shows the lights in the right part of the picture and the specter in the left part. There is street lights, lights from houses and light from a train that went by during the exposuretime. That picture is from the valley Midtre Gauldalen, about 60 km north of Hessdalen. It is used the same type of film and the same type of grating as fig. 2 and 3.

Fig 9 - The optical specter of streetlights, train and houses


Other Case

This case is also from the Project Hessdalen field investigation in 1984.

Three pictures was taken by Arne P. Thomassen, Wednesday 25.January at 7.10 p.m. A yellow light, as bright as Venus, stood still a couple of minutes in south-west, about 20 degree above the horizon. Suddenly it started to move towards north. Arne did take totally three pictures with a camera with grating and mounted on a tripod. Just after he had taken the pictures, the light suddenly speeded up and disappered behind the mountain Fjellbekkhøgda.

The F-score on this was F6. That was mainly because of the high speed. No plane show such a speed. Arne have been much out watching and he have seen many planes. He stated that this speed was much higher than any plane. If this statement not had come, the light would have got a score less than F5, probably around F2. Because of this suddenly increase to this high speed, it got a F6.

Fig 10 - Optical specter from 560 to 630 nm

In fig.10 you can see the optical specter. The specter was very weak, but it is possible to see something that looks like a continious specter from 560 to 630 nm.

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Last update 08 May 2003 09:27:27.