Twenty Years of Serendip, The Berkeley Seti Effort: Past Results and Future Plans

Abstract The Berkeley SETI effort has been ongoing for more than twenty years. During this period we have carried out extensive SETI searches, but of at least equal importance, we have been on the forefront of instrumentation development, the development of interference rejection and detection algorithms, and educational efforts. Our instrumentation has evolved from a 100 channel spectrometer (SERENDIP I) to our latest machine (SERENDIP IV) with 168 million channels. In addition to supporting our SETI work, our hardware has been used by NASA for RFI surveys and to check the Mars Survey relay transmitter. Our designs have influenced several of the major SETI hardware systems, and a SERENDIP III system is currently being used in the Ohio State SETI group. Our hardware has also been incorporated in pulsar instrumentation at NAIC (Arecibo), NRAO (Greenbank) and Bonn, Germany. We have just completed a 4 year search at the world’s largest radio telescope at Arecibo. We covered 93% of the observable sky at least once, and 44% of the sky at least 5 times, with a sensitivity of ~ 3 × l0 −25 Wm −2 . We collected and analyzed information from over 10 14 spectral bins and logged and analyzed over 2 × 10 8 signals of potential special interest. We have developed extensive analysis programs to identify and remove interference and to search for signal characteristics which are expected from an extraterrestrial signal. Our algorithms were successful in removing all but 0.01% of spurious RFI in the Arecibo data set. We have involved over 30 undergraduate and graduate students in our effort, and 5 Master's theses have been awarded for work on the SERENDIP project. Our next effort will use our SERENDIP IV hardware at Arecibo Observatory to carry out a 21 cm survey of the Arecibo sky.