The COSETI Observatory
Disadvantages of the optical approach to SETI.
- Transmitting civilizations need to have precise knowledge of relative motions between stars and be capable of precisely point-ahead targeting their laser beams.
- In the galactic plane, ultra-violet, visible and near-infrared lasers suffer significant attenuation over distances greater than about 10,000 light years.
- An “All-Sky Survey” by a targeted civilization is not sensible because there are too many pixels to search in the celestial sphere.