Dear Peter,

 

In special relativity, in the observer’s frame the speed of light is fixed at c. The SR postulate is that the speed of light is the same to every observer (i.e., in every observer’s frame). So any light from any observed source anywhere in the universe in his frame – regardless of its motion --  will be seen IN THE OBSERVER’S FRAME as moving at c with respect to him.

 

Of course, as the object varies its speed, the color (frequency) of its light observed by the observer can be seen to shift up or down a bit in the spectrum, depending on the relative direction.

 

Best wishes,

 

Tom Bearden

In "Fer de Lance" I learned why an object moving with respect to an observer appears to gain mass [Page 39] in accordance with OGR.
 
Can you also explain why any motion toward or away from a light source has no effect on c as measured by the observer, in accordance with OSR?
 
Peter