[Zhou (Mick)]

I will go off on a little bit of a tangent here:

When you are looking at a distant object through a telescope you are not actually viewing the photons from that object. If a photon is lucky enough to make it through our atmosphere unimpeded it will hit the objective lens (or primary mirror) of the telescope. It will then be absorbed by an atom within the lens and another one will be re-emmitted, this constant absorb-emit of photons within a substance is why light appears to travel slower through transparent objects compared to a vacuum. The same process will happen countless times in the eyepiece of your telescope and then your eyes. Finally what you end up seeing is photons emitted from from the atoms that the vitreous humour in your eyes are composed of. The same thing happens when photons are making there way from the centre of the sun to the its surface.