D.-E.Liebscher (Astrophysikalisches Observatorium Potsdam)
P.Brosche (Sternwarte der Universität Bonn)

Three traps in stellar aberration

The effect of aberration seems to be one of the simplest phenomena in astronomical observations. Nevertheless, it has a long and pertaining history of misunderstanding and wrong interpretation. In the time just before the advent of the theory of relativity, aberration and drag of the aether (as found in Michelson's experiment) are interpreted as contradiction. This contradiction vanishes with the theory of relativity. More obstinate is the misunderstanding that the aberration depends on the relative velocity of source and observer. In the twenties, some physicists and astronomers believed that the consequences of such a relativity, wrongly supposed but never found, would constitute a firm argument against Einstein's theory (Hayn, Tomaschek, Osten, v.Brunn, Courvoisier, Mohorovicic). History forgot their argument, but it is difficult to find a correct explanation of their error (Emden). Instead, the subject is forgotten, and one can conjecture that it is because of the political side of the argument. This attitude takes its revenge: Misunderstandings are still handed down from textbook to textbook.

Bradley's explanation is found everywhere, beginning with
The retardation in the particle picture is, for instance, noticed and tested in
The absence of wave-front aberration (in aether theories) is noticed in
Fresnel's explanation is found more rarely, beginning with
The absence of the aberration of wave-front normals is overlooked, for instance, by
The aberration of wave-front normals requires a relativity of simultaneity. This can be found in
The aberration should be a matter of relative velocity betweeen observer and source. This error is, for instance, outspoken seriously or by neglect in
An active aberration is expected (erroneously) by
No active aberration is observed. This is (correctly) stated by
The absence of active aberration is (erroneously) believed to be an argument against the theory of relativity by
That no active aberration is to be expected, is (correctly) stated by
Here you will find the Poster.