Introduction to Radobs Optical SETI Files

Radobs 00

This copyrighted series of over seventy RADOBS text files were written and
uploaded onto Ohio State's private.radobs bulletin board over the past
two years.  These files contain original material which delineates my
(the Sysop, Dr. Stuart A. Kingsley) Optical SETI rationale.

The material for the six-part EJASA (the Electronic Edition of the
Astronomical Society of the Atlantic, Vol. 3, No. 6, January 1992) paper,
which can be found in this conference area (2 - Optical SETI) in a
compressed form under the file name EJASA306.ZIP, is based on the ideas
developed during the time that these RADOBS files were written.

The reader should be aware that these files amount to an historical record
of how the author's ideas developed, so that some contradictions will be
found in later documents.  Minor corrections have been made to some files
where I have become aware that there are some numerical errors.  The
observant reader will notice that there was a shift in emphasis after the
first files were written, as I became more confident that it was reasonable
to suggest that ETIs had the technical prowess to produce optical
transmitter powers in excess of 1 GW, and correspondingly higher EIRPs.

When I first started looking into the "sensibility" of the optical approach
to SETI, I was rather "conservative", and thought that about 100 MW per
beam, and corresponding EIRPs, would be a reasonable limit to ETI
transmitter performance.  However, as I went into this more deeply, and
read what the very limited literature on Optical SETI had to say about
powerful optical transmitters and wide bandwidth communications, I realized
that perhaps I had been too conservative!  Thus, I no longer talk about
1 GW transmitter powers as being the exception, rather as being more
typical of what we might expect.  Indeed, but for this change, it would not
be reasonable to argue for the concept of Amateur Optical SETI, as the
received signals would be too weak.

Note that this early conservative approach on my part has nothing to do
with the practice of normalizing transmitter powers to 1 kW, single
transmitter apertures to 10 meters, and signal bandwidths to 1 Hz.  This
has been done throughout the succeeding documents only as an engineering
technique for simplifying subsequent performance calculations.

The essence of my Optical SETI rationale, then and now, is that ETIs have
the technical prowess to aim very narrow optical beams (visible or
infrared) into nearby star systems, beams whose diameters are as small or
smaller than the zones of life surrounding such stars, yet are assured of
striking their intended planetary target.  In a nutshell, this is one of
the main points of contention between my viewpoint and that of majority of
the SETI community.


Composition Date: November 6, 1991
Revision Date: June 1, 1992
File: RADOBS.00


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* Dr. Stuart A. Kingsley, CEng,                                           *
* Consultant,                                                             *
* MIEE, SMIEEE,                                                           *
* The Planetary Society,                                                  *
* Space Studies Institute,                                                *
* Columbus Astronomical Society,                                          *
* Volunteer, SETI Group, Ohio State.                                      *
*                                                                         *
*                                    "Where No Photon Has Gone Before &   *
*                                   The Impossible Takes A Little Longer" *
*                                                 __________              *
* FIBERDYNE OPTOELECTRONICS                      /          \             *
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* CompuServe: 72376,3545                                                  *
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