From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Apr 25 2003 - 09:45:20 PDT
ARECIBO DIARIES (1): LOCATION IS EVERYTHING
By Seth Shostak
>From Space.com
15 April 2003
At first glance, Puerto Rico seems a strange place to eye the sky. A
tilted block of land guarding the eastern end of the Greater Antilles,
this island boasts no soaring mountains on which an optical telescope
could perch, nor an unpopulated outback that would suit the signal-
sensitive ears of a radio array.
What Puerto Rico does have is geology and location. Stretching across
the island's northern edge from the suburbs of San Juan to the western
town of Aguadilla is a bumpy, limestone terrain known as karst.
Pockmarked from thousands of millennia of rain, the karst is a jumble of
haystack hills and broad sinkholes. One of the latter, about 8 miles
south of the coastal city of Arecibo, is a perfect natural dimple to
house the world's biggest single-dish antenna: the Arecibo radio
telescope.
Read the full article at
http://www.space.com/searchforlife/shostak_arecibo_1_030415.html.
________________________________________________________________________
THE STARS OF PROJECT PHOENIX: THE BEST ARE NOT ALWAYS THE BRIGHTEST
By Peter Backus
>From Space.com
17 April 2003
April nights at Arecibo find Orion the Hunter high overhead. Red
Betelgeuse (the eastern shoulder) and blue-white Rigel (the western
knee), plus the three stars of Orion's belt form an easily recognized
and spectacular constellation from any latitude. Here, away from bright
city lights, Orion and the Milky Way's hazy band of star clouds stand
out against a black velvet sky. So many stars! So little telescope
time!
Unlike other SETI programs, Project Phoenix targets individual stars
rather than scanning the sky, which is mostly "blank," from our point of
view. In a vast sky full of stars, only a fraction are likely to have
life-supporting planets and be near enough for us to detect radio waves
transmitted at a reasonable power. Therefore, the SETI Institute
conducts a "targeted" search of selected stars. This strategy has many
advantages over scanning the sky. By choosing particular, relatively
close stars and observing each star for a long time, we are sensitive to
lower power transmitters over a wider range of frequency channels for
more types of signals.
Read the full article at
http://www.space.com/searchforlife/seti_stars_030417.html.
________________________________________________________________________
ARECIBO DIARIES (2): NARROWING THE SEARCH
By Seth Shostak
>From Space.com
18 April 2003
...By 1611, Galileo had built a yard-long, tubular instrument fronted by
a small, bubbly, one-inch lens. It boasted an unimpressive 20x
magnification. Peering through this toy-like device, he was able to see
the four large moons of Jupiter. This discovery changed our paradigm
for the solar system, and earned Galileo endless column inches in
astronomy textbooks. For Galileo, setting up for observing was pretty
straightforward: (1) Take telescope outdoors, (2) position eyeball near
the small end, and (3) make groundbreaking finds.
...For SETI, it's different. We're hunting for narrow-band signals--the
very same type as the man-made interference that fills the airwaves.
This RFI (Radio Frequency Interference) can clearly frustrate our
search. To avoid this problem, we take a cue from Charles Messier, the
18th century French astronomer who tried to help comet seekers by
cataloging all the potentially confusing fuzzy objects in the sky. On
our first day out, the Project Phoenix team points the telescope
overhead, and locks it down. We then do "RFI scans" by slowly stepping
up the microwave dial and noting all the narrow-band signals, and even
some (such as GPS broadcasts) that are a bit less narrow. These are
cataloged into an on-line database that can be used during the search to
identify (and quickly toss out) persistent terrestrial signals.
Read the full article at
http://www.space.com/searchforlife/shostak_arecibo_2_030418.html.
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