Optical SETI Map Conferences Map Illustrations Map Photo Galleries Map Observations Map Constructing Map
Search Engines Contents Complete Site Map Tech. Support Map Order Equip. Map OSETI Network

Search WWW Search www.coseti.org Search www.oseti.net Search www.photonstar.org Search www.opticalseti.org

colorbar.gif (4491 bytes)






1. Quantum noise disadvantage is overcome by antenna gain advantage.
2. Planckian starlight noise reduced by very small optical detection bandwidth of heterodyne receiver and diffraction limited telescope operation.
3. High Doppler shifts not important when we don't know the "magic frequencies", and if we can tune over all frequencies.
4. High Doppler chirps (drifts) at the transmitter may be compensated by the aliens. Local Doppler chirps at the receiver may be compensated by de-chirping the local oscillator laser.
5. Laser linewidths can be obtained which are less than 1 kHz. Bandwidths of optical transmissions likely to be much greater than 1 kHz.
6. Beamwidth not limited for spaced-based optical telescopes or ground-based adaptive optical telescopes. Aliens would not find it too difficult to aim a beam with a beamwidth 0.01 arcsecond, to fall at a specified point within a nearby star system. At ranges of hundreds of light years and greater, the beam only has to be aimed at where the star will be in the round-trip time, to strike all the planets in the star system.
7. Other that the CO2 laser frequency, we don't presently know what are the "magic frequencies" in the optical spectrum. However, this just makes the search more difficult - not impossible.
8. There are many families of lasers available to cover the range of frequencies of interest. If we can narrow down the specific "magic frequencies" we can save considerable effort in having to develop special lasers, and substantially reduce the search time.
9. Directed alien transmissions in the optical regime are expected to be strong and sufficiently wideband to be unaffected by interstellar spectral broadening. Hence the number of frequencies or bins to search may not be much greater than in the 1 GHz to 10 GHz microwave regime.


Home Glossary
SPIE's OSETI I Conference SPIE's OSETI II Conference
SPIE's OSETI III Conference
The Columbus Optical SETI Observatory
Copyright , 1990-2006 Personal Web Site:
Last modified:  10/28/06
Contact Info