The village of Trans-en-Provence is located 3 km south of Draguignan. Mr. and Mrs. Nicolai live on a property situated 2 km east of Trans, on the side of a hill overlooking the valley of the Nartuby river (Figure 1). This valley is oriented east-west and contains numerous orchards and small agricultural plots. The sides of the valley are covered with woods and with Mediterranean vegetation. The sparse dwellings have their openings (windows, doors) facing the valley. Many terraces dug into the hillside make possible more intensive use of the soil for cultivation. Retaining walls, locally known as "restanques" and generally built out of native stone, have an average height of 2 m.
The plot of land owned by Mr. and Mrs. Nicolai is located some distance away from the D47 road, on the north side of the valley. A dirt road runs along the property. It ends 400 m away at an isolated farmhouse. The property is structured in such a way as to make the best possible use of the contour of the hillside. The house is built over several levels of retaining walls and it is partially dug into the hill. The driveway is covered with asphalt at the level of the basement, 30 m away from the road running to the west. On the left side of the villa are some stairs leading to the living quarters. To the right a slope prevents access to the upper terrace, which is reached through the dirt road previously mentioned.
This terrace or platform is linked to the other levels through stairs located behind the house. However, it is almost never used, except to play "pétanque" (a game of skill using metal spheres, very popular in the South of France). To the northeast side of the hill are two higher levels (labeled level two and level three on Figure 2), each about one m high. Two structures rest on these levels: a pumphouse at the edge of level three and a stone cabin straddling both levels.
Above the larger platform are two levels that are used as vegetable gardens about 50 m long and 2.5 m wide. Woods of conifers and leaf-bearing trees some dozens of meters tall, surround the property, except on the southwest side facing the Nartuby valley. No obstacles of any significance, such as power lines, telephone lines or TV relays, are visible from the Nicolai property. In fact, from the large platform where the phenomenon was seen, the visual field is totally open to the Southwest over nearly 180 degrees. The only obstacle to the line of sight is the landscape on the other side of the valley about 2 km away (Figure 3).
At the time of Mr. Nicolai's observation the nearest weather station registered the following measurements 17 km to the southwest of the site:
- Temperature: 6.8 degrees Centigrade
- Humidity: 30%, no precipitation
- Wind: Southeast at 2 m/s
- Clouds: 2/8, good visibility.