The green line is a trail of a meteor that crossed the constellation Cepheus and the Milkyway (seen as background) during a longer observing session. It occured during a single exposure of 15 sec, f=85 mm, f/2,8 and ISO 1600. . Unfortunately the trail was not captured completely. The field of view was too small. The size of the field is about 10 x 15 degrees; i.e. 20 x 30 full moons.

The greenish colour is caused by the element magnesium, apperently present in the dust particle that caused the meteor trail