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ZL2VAL > SETI 22.11.02 15:07l 108 Lines 5621 Bytes #-7778 (0) @ WW
BID : 7314-ZL2VAL
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Subj: Looking back
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Sent: 021122/1005Z @:ZL2AB.#46.NZL.OC #:13905 [New Plymouth] FBB7.00g $:7314-ZL
From: ZL2VAL@ZL2AB.#46.NZL.OC
To : SETI@WW
Report from the Field: A Personal Perspective
By Peter Backus
SETI Institute
posted: 08:25 am ET
21 November 2002
Sometimes I walk around the dish in moonlight. The 300-meter dish is
impressive, even overwhelming, during the day. At night, under the soft
light of the Moon, and with wisps of fog in the bowl, it takes on
another dimension. The huge dome and massive feed support structure,
suspended hundreds of feet above, seem to float weightless in space.
It’s an inspiring scene and helps to puts things in perspective.
Tonight, I'm thinking about how I came to be here, at this telescope in
the moonlight.
The story begins in the spring of 1982 when Dr. Paul Horowitz, a
professor at Harvard University, brought his new "Suitcase SETI" system
to Arecibo. "Suitcase SETI" was designed specifically for SETI, and to
search for signals in real time. These two features were revolutionary
at the time as scientists had been using signal processing equipment
designed for more conventional radio astronomy and analyzing data as
long as a year after collection.
But that was not all; "suitcase SETI" used the latest integrated
circuits to perform Fourier Transforms, the mathematical technique that
splits the radio spectrum into channels, and was controlled by one of
the first desktop Unix computers, which also analyzed the data and
presented results. With these and other advances, Horowitz's system
marked the dawn of SETI's "modern era."
While Horowitz was building "suitcase SETI" on a fellowship at Stanford
University, I was just a few miles away at NASA's Ames Research Center.
As a research associate, I studied pulsars with Ivan Linscott who was
also working with colleagues at Stanford's STAR Lab on a
proof-of-concept system for the NASA SETI Program. These connections
led to my writing a few lines of code for Suitcase SETI. Then, when our
observing runs at Arecibo overlapped, Ivan and I collected data on
"giant pulses" from the Crab Nebula pulsar and helped with Suitcase
SETI observations. It was a very busy time at Arecibo, but very
rewarding. It was during this visit I discovered the effect of
moonlight and fog on the dish.
Meanwhile, back at Stanford, the prototype of NASA's dedicated SETI
signal processing system, the Multi-Channel Spectrum Analyzer 1 (MCSA 1)
was taking shape. Much bigger than a suitcase, it occupied most of a
six-foot tall electronics rack and used the latest chips to generate
channels with even greater filtering capability than the smaller
system. The greater performance of MCSA 1 would allow NASA scientists
to search with extreme sensitivity for ET's signals against the
background noise of strong radio signals from Earth's own technology.
I was interested in how the signals would be detected, especially ones
that change frequency with time. Astronomers searching for pulsars have
to deal with similar problems so I proposed to apply pulsar search
techniques to SETI. I received a fellowship to work with the NASA SETI
Program. For several years we worked on developing and testing signal
detection algorithms in the lab and eventually in the field at NASA's
Goldstone Station in the Mojave Desert. Moonlight on the desert is
pretty but it's not Arecibo.
During this time, the SETI Institute was formed (in 1984) and by 1989,
Institute scientists brought the MCSA 1, along with a control computer
and signal detection software, to Arecibo. That search was the most
sensitive SETI search ever conducted, yet it was most useful as a test
of designs and techniques being developed for the even larger Targeted
Search System (TSS).
Drawing on lessons from the 1980's, the TSS used cutting edge
technology. With incredible filters and exquisite signal processing
performance the high-speed custom computer systems of the TSS analyzed
data in real time allowing results to be evaluated immediately by
sophisticated software. Easily the most capable search system ever
assembled, in the first few minutes of operation the TSS did more
searching than all previous SETI programs combined. What a thrill it
was for my colleague, Dr. John Dreher and me when we operated the TSS
during those first minutes a decade ago.
Now I am at Arecibo again. The moon is nearly full. The SETI Institute,s
Project Phoenix team is gathering here and at the Jodrell Bank
Observatory in England. For us, this is a time to look forward and
back. This will be the last time we use the TSS. It has served us well
for ten years. We await the arrival of its successor, the New Search
System. The NSS is designed to evolve as new technology becomes
available. It is designed with the future in mind. However, until it
moves to the Allen Telescope Array in late 2004, the NSS will continue
the search here at Arecibo, listening for ET in the moonlight.
====================================
73 de Alan
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Whacky signs
~~~~~~~~~~~~
A sign posted in Germany's Black Forest:
It is strictly forbidden on our black forest camping site that people of
different sex, for instance, men and women, live together in one tent
unless they are married with each other for that purpose.
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