Amazing idea for Arecibo replacement

[Dick Jacobson]

There is a proposal to replace the Arecibo dish with a flat 300-meter wide platform. 1000 smaller radio dishes would be mounted on the platform. The ENTIRE platform would be tilted using hydraulic actuators to track objects. It would have a much greater field of view and range of sky visible than the old collapsed telescope, and would be able to view the supermassive black hole at the center of the Milky Way. Sensitivity would be double that of the previous scope, and radar power would quadruple. Wavelength range would also be greater.

The estimated cost is $400 million, which would be a challenge. Puerto Rico has only one non-voting representative in Congress, and he is about to retire.

There is a detailed article about this proposal and the collapse in Science magazine, but you have to be a subscriber to read it. You might be able to find some information by looking up "Next Generation Arecibo".

[Dale Smith]

A circle 300 meters wide (984 feet) has an area of 760,852 square feet. This is approximately equal to the flight decks of 3 aircraft carriers or the total exterior area of one of the old Twin Towers (before 9/11). That is quite some area to tilt. It would have to be very massively constructed to not have major problems with sagging during tilting. Tilting it by just 5° would mean raising one side by about 85 feet – roughly the height of a 7 story building. I would think subdividing the flat into 1000 pieces (i.e. 1 for each collector dish) would be much (!) easier to construct and tilt. It would also reduce the potential for catastrophic failure on the scale of the recently deceased Arecibo array.

Or am I misunderstanding the proposed layout?

[Dick Jacobson]

They originally considered a fixed dish like the previous one, or an array of independently steerable antennas, but later went with the idea of a giant steerable platform supporting multiple fixed dishes. At maximum, the tilt would be more than 45 degrees from horizontal and the edge would be higher than the existing towers. I estimate at least 210 meters high. Steering "will be a great mechanical challenge". Indeed!

[Deane Clark]

Would they have to worry about Dobson’s hole?

[Dick Jacobson]

Would they have to worry about Dobson’s hole?

I would think not, if the scope is pointed by means of hydraulic actuators around the rim. But I don't know the details of the plan.