Q. about Bradley's Stellar Aberration

[Zorba]

I have been reading in my book on Special Relativity (A. P. French, Chapman & Hall) that stellar abberation as discovered by Bradley, only made sense to physicists at the time in the context of a wave/ether model of the propagation of light IF the Earth moved with respect to the ether.

I don't really understand why this is the case, it seems to me as though abberation would occur even if the Earth were stationary w.r.t. the ether from the wave/ether perspective... anyone can shed some light on why this is the case?

EDIT: Oh god, I just realized the horrible (unintended) pun I made at the end there, sincere apology...

 

[yuiop]

Have a look at the attached diagram and see if it helps.

In the first sketch the telescope and Earth is moving to the right transverse to the vertical direction of the light ray coming from the star and no aether is assumed. In the second sketch there is an aether co-moving with the Earth and the telescope and the light ray acquires a horizontal velocity component equal to the motion of the Earth and the telescope and no aberration occurs. The light ray acquires a horizontal velocity because it moves with respect to the aether medium.

 

[Zorba]

Ah yes, I get it now, it seems so simple. Cheers.