To solve this equation for an extended source, an additional integration would be required to sum the contributions made by the individual points in the source.
Prof. Douglass has also worked on chaos and frequency drifts of spectral lines of extended sources.
An extended source will therefore change the mutual coherence of the fringes, reducing their contrast.
Other more advanced methods were developed starting in the early 1990s that can better handle extended light sources than the edge-ray method.
It also faces the problem that for extended sources, nearby emission lines will overlap.
Localized fringes result when an extended source is used.
The light seemed diffuse, as if from some extended source, a glowing ceiling somewhere out of her view.
The coma contains, besides water vapor and H30 ions, an extended source of carbon monoxide.
Unlike most radio telescopes, the MRT can 'see' very extended sources.
If waves are emitted from an extended source, this can lead to incoherence in the transversal direction.