Thanks so much dear! (L)
This is indeed what you call a "star trail photo". For the photo featured here, I let the camera take pictures on its own for almost one hour (210 photos in total). I had more data but even though the skies were very clear that night, some clouds appeared at times which made them not useable. So it takes a lot of time and then you need to do some editing... but happy with the result in the end :)