I have been wondering and this may be a stupid question but i ask anyway.

Why can't we use telescopes to find signs of ET?

If they are the masters of space travel they must of made big structures in space. Why don't we use telescopes to view around planets and see if we could spot anything?

We are being watched. A Telescope(s) about the size of Earth. It will watch life. A 12 inch Meade outside of the Oort cloud, would be suffcient enuff, and I think there might alot traffic of Life..gtg n gn.

As far as current technology is concerened, we cannot build a telescope capable of seeing outside our solar system. We know there is no life on those other 8 planets already so... no alien spotting for the moment.
Also we do not know that aliens are 'masters of space travel' they could be anything from single cell organisms to primitive apelike creatures, so even if we could see they may not have built anything anyway

And Primordial....get some sleep dude