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Conference 7.286::space

Title:	Space Exploration
Notice:	Shuttle launch schedules, see Note 6
Moderator:	PRAGMA::GRIFFIN

Created:	Mon Feb 17 1986
Last Modified:	Thu Jun 05 1997
Last Successful Update:	Fri Jun 06 1997
Number of topics:	974
Total number of notes:	18843

950.0. "New SETI system goes on line at Harvard, MA" by IROCZ::MORRISON (Bob M. LKG1-3/A11 226-7570) Tue Oct 31 1995 10:11

  (See also note 760.*, whose last reply is a year old.)
  I read in the paper that a new system was dedicated yesterday at the Oak
Ridge Observatory in Harvard, MA to do a more thorough search for extra-
terrestrial life (SETI). This system has a billion channels for listening.
A less sophisticated SETI has been going on there for about 10 years.
  The new system is called BETA. The Boston Herald says that this is "a new
radio telescope", but I am skeptical because they already have (and have had
for decaces) a huge radio telescope there; the previous SETI was retrofitted
to the existing dish. Does anyone know if they really did build a new radio
telescope this time?
  I'm quite interested in this because the observatory is a mile from my home.
I walked around the grounds a few years ago but have never taken a formal
tour.

T.R	Title	User	Personal Name	Date	Lines
950.1		skylab.zko.dec.com::FISHER	I've advocated term limits for 19 years! - Rep Bob Dornan	`Tue Oct 31 1995 12:43`	14
	I was there yesterday at the dedication. It was very exciting to see Frank Drake and Paul Horowitz, and to see the official turn-on. We also got a tour through the control room. There was a graduate student around to answer questions. They have several gigs of memory, largely used by special hardware to to 250-million point (I may have the number wrong) FFTs. Then then transfer the FFT output to 21 Pentium PCs to do data reduction. Most exciting, after a while they moved the dish so it pointed straight up and we got to climb up into it. Some people even climbed the parabolic surface up to the edge to look off at Boston. I was not quite that brave. I was quite amazed how strong the thing is, though. Burns
950.2	Upgrading of parts of a system defines "new" legitimately	NETCAD::BATTERSBY		`Tue Oct 31 1995 17:06`	8
	It's new electronics. So in a sense, the Herald is right the new electronics combined with the existing dish makes for a "new" radio telescope capable of improved resolution & performance. Stretching the definition of things is not new to the print media. I've been up there in years past, & would like to go through one of their tours now that they have upgraded things. Bob
950.3		skylab.zko.dec.com::FISHER	I've advocated term limits for 19 years! - Rep Bob Dornan	`Wed Nov 01 1995 09:04`	34
	Oops...I guess I did not read the entire first post. Yes, Bob is 100% correct. The stuff in the control room is new. The dish is old. (Gave one pause to go climbing around on it, actually!) I suspect that there may be at least some new electronics in the dish as well. They described that one of the mechanisms for detecting false alarms is that there are two antennae in the dish offset from one another by a small amount on the East/West line. A real extra-terrestrial signal will show up first in the east feedhorn and then in the west (as the Earth rotates). If it seems to do the right thing, they sweep the dish to the east of the source and let it pass through again. In any case, I believe that they must have added the new receivers. I'm not sure what actually lives in the antenna itself. Surely they must have LNAs (low-noise amplifiers), but I'm not sure if they mix the signal down to a lower frequency or not. I do know that the A/D converters are in the building, and I know that the FFT processing is the way they manage to get the 250 million channels (at about 1/2-Hertz wide). That means that we actually have some RF (or IF) going into the building. You know, I wish I had asked the following question, but I had not worked it out at the time. The dish appears to only move on a single axis. That axis appears to run E/W. There was an axis that ran parallel to the Earth's axis, but I believe they only use that once in a great while (maybe only once 40 years ago!) to calibrate. It was clearly not used frequently. In any case, given that this is all true, how do they sweep the east of the source to let it come through again? I'm sure from the explanation that they don't wait till the next day...that was the whole point of this system...you can get some checks right away. I'm confused. Do they move the feedhorns? (I wonder how far you can move them and still be within a region where you are gettin reasonable signal from the dish?) Burns
950.4	Inside view	NETCAD::MORRISON	Bob M. LKG2-A/R5 226-7570	`Fri Apr 11 1997 11:46`	14
	This winter I took an adult education course in Harvard (town) taught by Joe Caruso, an astronmer at Oak Ridge Observatory. We went to the observatory twice. We spent most of the time on optical astronomy, but I talked him into taking me and part of the class on a tour of the SETI equipment. It actually was sort of an anticlimax. I had pictured a large roomful of equipment. In fact, the equipment fills an area of about 100 square feet. There is a "bakery cart" on which the 21 Pentium computers reside (just the boxes, no monitors or keyboards), butted up against each other. The BETA array itself consists of several hundred circuit boards in a single-bay rack. There is a control panel consisting of a workstation computer and a rack of gauges and dials. That's about it. It's entirely run by remote control from Cambridge. There is nobody in the building most of the time. They have a dedicated Ethernet link to Cambridge to transmit the processed data.