This week we are re-sending out workunits from
March 2003 candidate reobservations.
We sent this data out to the SETI@home participants
before, but unfortunately, we made a mistake calculating
the speed the Arecibo telescope moves across the sky.
This mistake introduced a problem in some of the
screensaver's gaussian and pulse signal detection algorithms.
The miscalculation was introduced because of the new
receiver we used for the candidate reobservations (this receiver
has a smaller beam size), and the zig-zag pattern we
used to scan the area around each candidate.
Figure 1 on the right represents a zone of the sky in which we would search for a previously observed previously observed signal candidate. This zone is 10 arc-minutes high and 10 arc-minutes wide. (And arc-minute is equal to one-sixtieth of a degree.) The purple discs represent the sky coverage of our receiver's telescope beam (The beam has a diameter of 3 arc-minutes. For comparison, the candidates were initially observed using our old receiver, which had a beam size of 5 arc-minutes.) With some overlap, it takes our receiver 5 zig-zag sweeps to search for a previously identified candidate.
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Figure 1 |
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