- Joined
- Oct 6, 2002
- Location
- Germany NRW
by Amir Alexander
August 4 , 2004:
The view greeting morning hikers on the hills surrounding the Arecibo observatory on Wednesday, April 21, was unusual, to say the least. Down below, as always, was the giant 1000 foot reflective dish of the Arecibo radio telescope, the largest in the world; hanging 500 feet above the dish, at its reflective focus, was the familiar triangular platform that carries both the Gregorian dome and the needle shaped antenna used by SETI. But there, between them, was something else: a cylindrical metallic object, about the size of a large washing machine, hanging in mid-air and slowly making its way upwards from the surface of the dish towards the Gregorian dome.
The antenna platform, 500 feet above the Arecibo dish. The Gregorian dome at the center and the needle-shaped antenna currently used by SETI are clearly visible.
Courtesy of the NAIC - Arecibo Observatory, an NSF facility.
The Multi-Beam Solution
This has been a serious problem for SETI scientists such as Dan Werthimer, who believe that the best chance to discover ET is by looking at the entire sky. To get around this, Werthimer and his team have devised their ingenious “piggy-back” strategy. They placed a receiver permanently above the Arecibo dish, at the base of the needle-shaped antenna. Though the SETI team cannot direct the telescope, the SETI receiver collects data from whichever point in the sky the beam happens to be pointed at. Given enough time, the telescope will cover the entire band of sky visible from Arecibo, and the SETI receiver will consequently complete an entire sky survey. Using this innovative strategy, the SETI receiver has completed four sky surveys since its installation six years ago.
...
A multi-beam receiver at Arecibo can change all that: by looking at seven different points in the sky simultaneously, it can cover an area seven times larger than an ordinary single beam receiver. Naturally, this reduces the time it takes to cover the entire visible sky to a fraction of what it was.
...
What it All Means for SETI
How will all this affect SETI research? In several important ways, all of which add up to a major increase in the programs scope and sensitivity.
...
as part of the Alfa consortium SETI will now be part of systematic sky surveys that will take place regularly at Arecibo. And with the multi-beam receiver, these surveys will also be much faster than any single beam survey could ever be.
In addition, the SETI surveys will now be conducted at a much increased level of sensitivity. This is because the seven receivers that comprise the multi beam array are newer and much “quieter” than the old SETI receiver. This means they produce far less electromagnetic noise of their own, enabling them to distinguish much fainter signals from the stars.
...
Full Story at the Planet Society
Sir Ulli
August 4 , 2004:
The view greeting morning hikers on the hills surrounding the Arecibo observatory on Wednesday, April 21, was unusual, to say the least. Down below, as always, was the giant 1000 foot reflective dish of the Arecibo radio telescope, the largest in the world; hanging 500 feet above the dish, at its reflective focus, was the familiar triangular platform that carries both the Gregorian dome and the needle shaped antenna used by SETI. But there, between them, was something else: a cylindrical metallic object, about the size of a large washing machine, hanging in mid-air and slowly making its way upwards from the surface of the dish towards the Gregorian dome.
The antenna platform, 500 feet above the Arecibo dish. The Gregorian dome at the center and the needle-shaped antenna currently used by SETI are clearly visible.
Courtesy of the NAIC - Arecibo Observatory, an NSF facility.
The Multi-Beam Solution
This has been a serious problem for SETI scientists such as Dan Werthimer, who believe that the best chance to discover ET is by looking at the entire sky. To get around this, Werthimer and his team have devised their ingenious “piggy-back” strategy. They placed a receiver permanently above the Arecibo dish, at the base of the needle-shaped antenna. Though the SETI team cannot direct the telescope, the SETI receiver collects data from whichever point in the sky the beam happens to be pointed at. Given enough time, the telescope will cover the entire band of sky visible from Arecibo, and the SETI receiver will consequently complete an entire sky survey. Using this innovative strategy, the SETI receiver has completed four sky surveys since its installation six years ago.
...
A multi-beam receiver at Arecibo can change all that: by looking at seven different points in the sky simultaneously, it can cover an area seven times larger than an ordinary single beam receiver. Naturally, this reduces the time it takes to cover the entire visible sky to a fraction of what it was.
...
What it All Means for SETI
How will all this affect SETI research? In several important ways, all of which add up to a major increase in the programs scope and sensitivity.
...
as part of the Alfa consortium SETI will now be part of systematic sky surveys that will take place regularly at Arecibo. And with the multi-beam receiver, these surveys will also be much faster than any single beam survey could ever be.
In addition, the SETI surveys will now be conducted at a much increased level of sensitivity. This is because the seven receivers that comprise the multi beam array are newer and much “quieter” than the old SETI receiver. This means they produce far less electromagnetic noise of their own, enabling them to distinguish much fainter signals from the stars.
...
Full Story at the Planet Society
Sir Ulli
