Arecibo observatory to be demolished

[kerbiloid]

8 hours ago, RCgothic said:

I almost suspect that a thorough appraisal of the site's condition might have caused it to be condemned even before the first cable failed.

New world, new view.

Spoiler

 

[YNM]

14 minutes ago, kerbiloid said:

New world, new view.

You do realize the dish isn't solid right ? XD

[kerbiloid]

50 minutes ago, YNM said:

You do realize the dish isn't solid right ? XD

Yet.

[Delay]

I literally just heard of the collapse. That's 50 years of astronomical history gone in just a few seconds.

I would have wished for the telescope, if not used, to be at least preserved because of it's huge importance to astronomy. Alas, that definitely won't happen now.

[AHHans]

16 hours ago, YNM said:

The most damning part however was the fact that no one knew how deteriorated it has actually really become... which is the sad part to me, more than the eventual collapse.

Well, the first part that you skimp on when you run out of money is maintenance. And Arecibo was in trouble for 15 years or so, since the NSF decided that after all its budget cuts it had to save somewhere and that one of the places it could do without was the Arecibo telescope.

So in a way you could say that we at least got 10 more years or so of science out of it, compared to closing it when it started to become unsafe...

[YNM]

2 hours ago, AHHans said:

So in a way you could say that we at least got 10 more years or so of science out of it, compared to closing it when it started to become unsafe...

Why not just move out the instruments that are rarely used, or whose job can be done from other observatories ? That'd have lessened the load on the structure, therefore you don't end up with 5-story-building-crashing-down-150 m rubble wreck, you end up with vintage instruments probably in top notch state...
They could've lowered the platform and re-create a smaller dish radius (the mesh can be re-positioned) so you end up with less stress on the 50+ years old main cables (as for how that works, mind that hecause the cables are holding vertical loads at an angle for it to be taunt there has to be horizontal forces acting on it depending on how far is it from vertical, and lowering the platform would've meant less angle from vertical)...

While they did said it was quite redundant given multiple cables per tower, statically it's really not at all that redundant to start with (6 reaction forces is the minimum for stability, and there were only 6 groups of cables keeping the platform fixed, 3 main cable groups on 3 main towers plus three more that holds it down so it doesn't rotate too much) so failures are bound to be catastrophic.
If we take the recent (ok, 2017) hurricane into account, then I'd say that this structure is done even before it actually failed as it has gone through one extreme loading event (most buildings are only designed to hold them once in their lifetime). At least the NSF might've been able to salvage it properly back then.

Edited December 4, 2020 by YNM

[AHHans]

4 hours ago, YNM said:

Why not just move out the instruments that are rarely used, or whose job can be done from other observatories?

I guess there are two major reasons why they didn't move equipment out from the receiver platform: one is that they didn't think this was an issue before the first cable snapped and it was too late. (See my comment about maintenance, in particular I consider inspections a part of maintenance.) And the other is that removing equipment from the platform means that there are experiments (observations) that you cannot do. Swapping out the equipment requires serious manpower and time So it's not something that you want to do every other day. (Apart from the question how much it will help to remove two tons or so of receiver from a 900 ton platform.)

And you cannot just move to another telescope, it's not like they are sitting idle and just waiting that someone comes along and asks for observation time.

5 hours ago, YNM said:

They could've lowered the platform and re-create a smaller dish radius (the mesh can be re-positioned) so you end up with less stress on the 50+ years old main cables

The main reflector has one focal point. (Well "point".) You cannot just move the receiver from the focal point and still have a working telescope.

But in the end I think the main issue is: yes there were things that one could have done! But to actually do that you need to be aware of the problem in the first place! And if you don't inspect the cables well enough to know that at least some of them will fail at well below their design limit then there is a problem.

Or in other words: they say that at the golden gate bridge they are always painting somewhere, when they are done on one end, they start over at the other. On Arecibo they didn't do maintenance to the same standard.

[Dfthu]

23 hours ago, Elthy said:

snip

Just imagine being that drone operator and watching it collapse. Must of been freaky

[YNM]

9 hours ago, AHHans said:

But in the end I think the main issue is: yes there were things that one could have done! But to actually do that you need to be aware of the problem in the first place! And if you don't inspect the cables well enough to know that at least some of them will fail at well below their design limit then there is a problem.

Yeah, and honestly that's the saddest part of the whole thing - it failed out of neglect, all the while still being in full swing of operations for at least 2 years.

[phantom000]

I just want to cry...

[RCgothic]

PR's outgoing governor has committed to rebuilding Arecibo better than before with a larger aperture and more powerful radar. They've released $8m for cleanup. It's the beginning of something I guess, and I hope it continues.

 

 

 

[RealKerbal3x]

*crosses fingers*

[RCgothic]

An interesting article. I think the biggest takeaway is the chief scientist at arecibo doesn't want to replace it like for like, but with a compact parabolic reflector array on a tiltable platform situated within the arecibo depression. It'd have twice the sky coverage (including visibility of the galactic core) and five times the radar power. Current estimate is under half a billion dollars.

https://skyandtelescope.org/astronomy-news/arecibo-to-be-determined-future/

 

 

[Scotius]

I'd like to say it's a ray of hope. But realistically... we need to wait and see if anyone pledges any serious sum of money for this or any other plan of rebuilding.

[YNM]

2 hours ago, RCgothic said:

compact parabolic reflector array on a tiltable platform situated within the arecibo depression.

That'd be interesting if they actually approved it.

Well I hope they can go and see if they really need the place to remain supported or not. There's still the other telescope at Arecibo for now.

[JoeSchmuckatelli]

Love the idea - but comparisons like this always make me cringe: 

"A rough estimate puts the cost of such a facility at $454 million, less than the cost of producing and marketing Avengers: Endgame" 

https://skyandtelescope.org/astronomy-news/arecibo-to-be-determined-future/

The investment of $454m in Endgame retuned at least $2.8b... and while no one could know it would be record-breaking, given the popularity and performance of the predecessors was pretty much guaranteed to be hugely profitable.  IOW - the investors had 'a sure thing'.  But private equity is not likely to get any financial return on a rebuilt / upgraded Arecibo.  Yet that's not the point, is it? 

 

Arecibo (and other, similar installations) are not for the general entertainment of people or a profit making enterprise.  But they are hugely important to our advancement and understanding of the universe... I just wish we could express that in better ways than lines like that above. 

 

/rant. 

---     - - -     - - - 

Question - what is the difference between the science possibilities having a single large dish vs an array?  (I thought Arecibo's large size enabled it to resolve wavelengths that smaller dishes could not) 

 

[Ziggy Kerman]

21 minutes ago, JoeSchmuckatelli said:

Love the idea - but comparisons like this always make me cringe: 

"A rough estimate puts the cost of such a facility at $454 million, less than the cost of producing and marketing Avengers: Endgame" 

https://skyandtelescope.org/astronomy-news/arecibo-to-be-determined-future/

The investment of $454m in Endgame retuned at least $2.8b... and while no one could know it would be record-breaking, given the popularity and performance of the predecessors was pretty much guaranteed to be hugely profitable.  IOW - the investors had 'a sure thing'.  But private equity is not likely to get any financial return on a rebuilt / upgraded Arecibo.  Yet that's not the point, is it? 

If I'm trying to convince one of those, "We should cut NASA's budget because it doesn't help us." I point them to Spinoffs, NASA isn't there to make money, it's just a really good side effect. Same w/ the comparison
Here's some of my random comparisons-
Arecibo vs the price of Da Vinci's Salvator Mundi
Arecibo vs Stephen King
Arecibo vs Dr. Phil
Arecibo vs 45 of the most expensive parking lots

[StrandedonEarth]

F