My question is: In the context of this model do these two effects really compensate each other, and is: would that be a reason for stellar aberation to be independant of the medium?
The shortest explanation, using 17th century science with a tiny sprinkle of current science, is:
The velocity of starlight does not depend on the state of motion of the medium of transmission (vis. ether or air). Why? Because if it did, starlight that entered the Earth’s atmosphere would be swept along by the moving air (or the ether with the embedded light in it would be dragged along by the Earth moving through the ether) and the aberration effect would not exist or would vary in certain directions. (Bergmann, pp. 21 – 22).
Source: "Early Attempts to Understand the Velocity of Light - Chapter 7":
Introduction: "It can be a daunting task to attempt to sort out and explain, let alone understand, the labyrinth of false assumptions, invalid theories, irrelevant equations, false conjectures, paradoxes, and misinterpreted experiments that (during the last two centuries) have confused and distorted physics in general, and Maxwell’s concept of the constant transmission velocity of light at c in particular. Most prominently included within this labyrinth are the arbitrary concepts of stationary ether as an absolute reference frame; Newton’s absolute space and absolute time; the theories of ‘ether drag’ and ‘partial ether drag;’ the Michelson & Morley null results; Fitzgerald’s, Lorentz’s and Einstein’s contraction of matter theories; the misapplication of Galileo’s Relativity to light; the Lorentz transformation equations; and above all Einstein’s theories of relativity.
Since a basic understanding of each of the above is necessary to an appreciation of the current untenable situation and to its ultimate solutions, we will do our best, in this and later chapters, to state and explain such confusion and distortions in as straightforward, simple and understandable terms as possible. We will thereafter set forth and explain the real facts and the real solutions for the false assumptions, paradoxes and other problems that have been created and still exist.".
" Does the constant transmission velocity of a light ray at velocity c relative to the medium of empty space vary, depending upon the linear motions of the bodies toward which such light ray propagates? The first experiment that deals with this question was conducted around 1728, the year after Newton’s death. British astronomer James Bradley (1693 – 1762) devised an optical experiment designed to measure the magnitude of observed stellar parallaxes. (see Figure 7.6A) But in the process Bradley discovered that he had to tilt the telescope slightly in the direction of the Earth’s motion around the Sun in order to keep the viewed star in the center of the telescope’s field of view. (Figure 7.6B)
This tilting requirement, which Bradley had discovered by accident, was later called the “aberration of starlight.” (Goldberg, pp. 429-432) The angle that the telescope must tilt in order to keep the viewed star in the center of the field of view is called the “angle of aberration.” (Id., p. 431) Since Bradley already knew the Earth’s approximate solar orbital distance, he also knew the approximate orbital speed v of the Earth (30 km/s). He computed the distance which he had to tilt the upper end of the telescope (in order to compensate for the orbital speed v of the Earth) compared to the distance light had to travel from the upper end of the telescope to his eye (at the velocity of light). This ratio v/c was approximately 1:10,000. (Bergmann, pp. 21 – 23) From this ratio Bradley also computed the approximate finite transmission velocity of light to be 303,000 km/s. (Hoffmann, 1983, p. 49)
Among other things, the aberration of starlight also demonstrated that the velocity of starlight does not depend on the state of motion of the medium of transmission (vis. ether or air). Why? Because if it did, starlight that entered the Earth’s atmosphere would be swept along by the moving air (or the ether with the embedded light in it would be dragged along by the Earth moving through the ether) and the aberration effect would not exist or would vary in certain directions. (Bergmann, pp. 21 – 22)
The aberration of starlight also implied that light had a constant transmission velocity relative to the medium of empty space, regardless of the relative linear speed of its source body (the star). Why? Because the angle of aberration (the ratio 1:10,000) was always the same for every star, regardless of the star’s speed or direction of motion relative to the Earth. (Id., pp. 21 - 23)
In addition, and very importantly, the aberration of light implied that the relative speed or direction of motion of the body (i.e. the Earth) toward which such starlight propagates did not alter the transmission velocity of the starlight, again because the angle of aberration (the ratio 1:10,000) was always the same for every star, regardless of the relative linear speed of the Earth in two opposite directions during its solar orbital motion.".
[Bolding done by me, to permit skipping through the text rapidly.]
"The theory is "special" in that it only applies in the special case where the curvature of spacetime due to gravity is negligible. In order to include gravity, Einstein formulated general relativity in 1915. Special relativity, contrary to some outdated descriptions, is capable of handling accelerations as well as accelerated frames of reference.
As Galilean relativity is now considered an approximation of special relativity that is valid for low speeds, special relativity is considered an approximation of general relativity that is valid for weak gravitational fields, i.e. at a sufficiently small scale and in conditions of free fall. Whereas general relativity incorporates noneuclidean geometry in order to represent gravitational effects as the geometric curvature of spacetime, special relativity is restricted to the flat spacetime known as Minkowski space. A locally Lorentz-invariant frame that abides by special relativity can be defined at sufficiently small scales, even in curved spacetime.".