Einsteinians teach that the wavelength VARIES with the speed of the light source:

Stephen Hawking, "A Brief History of Time", Chapter 3: "Now imagine a source of light at a constant distance from us, such as a star, emitting waves of light at a constant wavelength. Obviously the wavelength of the waves we receive will be the same as the wavelength at which they are emitted (the gravitational field of the galaxy will not be large enough to have a significant effect). Suppose now that the source starts moving toward us. When the source emits the next wave crest it will be nearer to us, so the distance between wave crests will be smaller than when the star was stationary." http://www.fisica.net/relatividade/s...ry_of_time.pdf

The idea that the crests bunch up (the wavelength decreases) in front of the moving source is absurd. We have

(wavelength) = (speed of light as measured by the source)/(frequency as measured by the source)

All the three quantities in the above equation are invariable (do not vary with the speed of the source). If any of them varied with the speed of the source, by measuring the variation, Zoe (the source) would know how fast she is moving, which contradicts the principle of relativity of course:

https://newt.phys.unsw.edu.au/einste...eird_logic.htm

Since Zoe measures the wavelength to be invariable, Jasper measures the speed of light to be c'=c+v, not c:

https://pbs.twimg.com/media/D0U6R1RXgAEbxnQ.png

Pentcho Valev