Robert J. Bradbury (bradbury@www.aeiveos.com) Mon, 23 Aug 1999 19:40:04 -0700 (PDT) :
>At any rate, the major consequence of these "results", has
>been that only one astronomer (Dr. J. Jugaku in Japan) has
>seriously looked for Dyson Shells and he has unfortunately
>(in my opinion) focused these searches only on "visible"
>stars (exactly the same as the work being done by the both
>SETI camps [those who believe a radio carrier is the best
>communication method and those who believe that an optical
>carrier, e.g. lasers, is the best communication method]).
>
It seems that you left some observations out. The following is from Anders' Dyson sphere FAQ.
Amara
P.S. I used to work for Fred Witteborn.
I have found the following three searches for Dyson spheres:
DATE: 1980
OBSERVER(S): WITTEBORN
SITE: NASA - U OF A, MT. LEMON
INSTR. SIZE (M): 1.5
SEARCH FREQ.(MHz): 8.5 microns - 13.5 microns
FREQUENCY RESOL.(Hz): 1 micron
OBJECTS: 20 STARS
FLUX LIMITS (W/m**2): N MAGNITUDE EXCESS < 1.7
TOTAL HOURS: 50
REFERENCE:
COMMENTS: Search for IR excess due to Dyson spheres around solar
type stars. Target stars were
chosen because too faint for spectral type.
DATE: 1984
OBSERVER(S): SLYSH
SITE: SATELLITE
INSTR. SIZE (M): RADIOMETER
SEARCH FREQ.(MHz): 37x10**3
FREQUENCY RESOL.(Hz): 4x10**8
OBJECTS: ALL SKY 3K BB
FLUX LIMITS (W/m**2): T/T =< .01
TOTAL HOURS: 6000
REFERENCE: 27
COMMENTS: Lack of fluctuations in 3K background radiation on
angular scales of 10**-2 Strd. rules
out optically thick Dyson spheres radiating more than 1 solar
luminosity within 100 pc.
DATE: 1987
OBSERVER(S): TARTER, KARDASHEV & SLYSH
SITE: VLA
INSTR. SIZE (M): 26 (9 ANTENNAS)
SEARCH FREQ.(MHz): 1612.231
FREQUENCY RESOL.(Hz): 6105
OBJECTS: G357.3-1.3
FLUX LIMITS (W/m**2):
TOTAL HOURS: 1
REFERENCE:
COMMENTS: Remote observation (by VLA staff) of IRAS source near
galactic center to determine if
source could be nearby Dyson sphere. Source confirmed as OH/IR
star.
In short, none have been observed yet.
References
Slysh, V. I., Search in the Infrared to Microwave for Astro-
engineering Activity, in The Search for Extraterrestrial Life: Recent
Developments, M. D. Papagiannis (Editor), Reidel Pub. Co., Boston,
Massachusetts, 1985
Kardashev, N. S., and Zhuravlev, V. I., SETI in Russia, paper presented
at the IAA/COSPAR/IAF/NASA/AIAA symposium on SETI: A New Endeavor for
Humankind, The World Space Congress, Washington, D.C., August 30, 1992.
To appear in a special issue of Acta Astronautica.
Jugaku, J., and Nishimura, S., A Search for Dyson Spheres Around
Late-Type Stars in the IRAS Catalog, in Bioastronomy: The Search for
Extraterrestrial Life, J. Heidemann and M. J. Klein (Eds.), Lectures
Notes in Physics 390, Springer-Verlag, 1991
***************************************************************
Amara Graps | Max-Planck-Institut fuer Kernphysik
Interplanetary Dust Group | Saupfercheckweg 1
+49-6221-516-543 | 69117 Heidelberg, GERMANY
Amara.Graps@mpi-hd.mpg.de * http://galileo.mpi-hd.mpg.de/~graps
"Never fight an inanimate object." - P. J. O'Rourke