archive: Re: SETI Theoretical question

Re: SETI Theoretical question

Dr. H. Paul Shuch ( (no email) )
Sun, 20 Sep 1998 17:38:14 -0400

At 01:52 PM 9/19/98 +0100, David Woolley wrote:

>Translating it just fast enough to compensate for the earth's rotation,
>will actually keep the source in beam longer and allow longer integration
>times. I believe this is what Arecibo does.

Yes, it is. But remember that Arecibo is a spherical, not a parabolic,
reflector. They do not lose gain in the process of deflecting the feed, so
they can track sidereal motion for perhaps three hours. (I'm working from
memory here -- it may be more). We would get only minutes of tracking
before our feed was so far from the focal point that dish performance began
to degrade.

H. Paul Shuch, Ph.D. Executive Director, The SETI League, Inc.
433 Liberty Street, PO Box 555, Little Ferry NJ 07643 USA
voice (201) 641-1770; fax (201) 641-1771; URL
email work:; home:

"We Know We're Not Alone!"