My first attempt to capture star trails, not too bad I think :)
This picture is a composition of 40 individual pictures composed in Photoshop. Each picture is taken at ISO 100, f/5.6 and 180 seconds for shutter speed. This final composition shows a total period of 120 minutes of star trails. Unfortunately two pictures are lost and the consequence is seen as two breaks in the final picture.
As Tehran is mega-city its light is too much to let more stars to be visible, therefore, only the most bright stars can be seen and lots of faint stars are absent.