Robert J. Bradbury (email@example.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.
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, GERMANYAmara.Graps@mpi-hd.mpg.de * http://galileo.mpi-hd.mpg.de/~graps
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