Star formations. Low light.. Why?

Hi all

I was just curious as to why a star formation is formed when taking long exposure shots at night time. Was just curious thats all..

Is it something to do with the way the camera picks up light from a bright source? eg lamp post..

I have been taking fair few long exposure shots for a long time, but just never really thought about it.. Just accepted it and thougth WOW looks cool..

I took these shots.. Heres a few examples of what i mean

It's to do with the aperture diaphram, I beleive.

The number of points in the stars is equal to the number of "leaves" in the diaphram.

Nice effect on your first shot though...

And I believe the smaller the aperture the more pronounced the star affect.

Ah that makes sense

Thank you!!

Was alwys curious thats all

In addition to the lens' iris forming the shape, the effect also has a lot to do with the fact that the light sources are WAY overexposed in most night shots where the photographer wants to get some detail in the darker portions of the scene.