[det dweller too]

I remember from my old physics that the speed of light is NOT constant. Light slows up based on the index of refraction. Glass is typically at ~1.3 refracvtion index. That means while the light is moving through your glass lenses, it's speed has slowed to 300,000/1.3 or about 230,770 kph.
We assume that space is a perfect vacuum with an IR of 1.0. There can be traces of gases which will effect the light speed traveling through it and make the IR something slightly higher than 1.0

[Richard Kimball]

I remember from my old physics that the speed of light is NOT constant.

Yeah, I remember the same thing, although not from physics class. I was a fine arts major and took classes that had topics like "our friend, the 7". However, if it is impossible to change directions without changing speed, then refraction and reflection prove the speed of light is not constant (at least I thought it did.) Also, it would seem logical to me that light would slow down after so long. If this is the case, wouldn't it be possible that the red shift in all the stars might mean NOT that the stars were moving away from us, but that the light was slowing down as it crossed the galaxy?