# Are the formulas that account for aberraion and doppler shift compatible?

1. Mar 12, 2009

### bernhard.rothenstein

Presenting the aberration of light effect we consider that two observers at rest in I and I' in the standard configuration equipped with laser guns start to emit light when they are instantly located at the same point in space. The problem is to find out a relationsship between the directions along which the same ray propagates when detected from the two involved frames.
Presenting the Doppler we consider the the same two observers mentioned above. What we haveto compare are the period at which say observer from I emits two successive wave crests (signals) from the same point in space the moving observer receiving them being located at two different points in space
That is an essential difference between the two effects.
Using the invariance of the phase of a plane wave many textbooks derive a formula that acounts for the Doppler and as a byproduct the formula that accounts for the aberration.
How could the two formulas be physically compatible?

2. Mar 12, 2009

### lalbatros

I think it is not different because the wavevector is a vector.

3. Mar 12, 2009

### bernhard.rothenstein

Thanks for you answer. I think that in a Doppler shift experiment we measure a period and reckon the frequency and we measure a wavelength and reckon the wave vector probably because frequency and wave vector are components of a four vector.
The stationary observer can measure the proper period at which the source at rest relative to him emits successive wave crests. The moving observer receives the two wave crests being located at two different points in space measuring the proper period of reception.
Starting with the invariance of the phase of a wave we perform the Lorentz transformation of the space coordinates of an event that takes place at a given point in space. Please be my next room physicist accepting to discuss the problem.
I like Baudelaire!

4. Mar 16, 2009

### bernhard.rothenstein

The Doppler Effect is concerned with two pair of events: The emission of two successive wave crests by the source and the reception of the corresponding wave crests by the observer. What we have to compare are the two time intervals: The time interval between the emissions of the time between the emissions and the time interval between receptions both measured, in the classical limit, in the same inertial reference frame. In the relativistic limit the mentioned time intervals are measured in the rest frame of the source and in the rest frame of the observer respectively.
Do you consider that it could lead to the accredited formula for the non-longitudinal Doppler shift?