We present a generalization and refinement of the Sachs-Wolfe technique which unifies many of the approaches taken to date and clarifies both the physical and the mathematical character of the method. We illustrate the formalism with a calculation of the behavior of light passing a moving lens on a Minkowski background.
Cite
@article{arxiv.astro-ph/9303020,
title = {Null Geodesics in Perturbed Spacetimes},
author = {Ted Pyne and Mark Birkinshaw},
journal= {arXiv preprint arXiv:astro-ph/9303020},
year = {2009}
}