Follow the reluctant adventures in the life of a Welsh astrophysicist sent around the world for some reason, wherein I photograph potatoes and destroy galaxies in the name of science. And don't forget about my website, www.rhysy.net



Friday, 1 November 2013

Happy Birthday Arecibo !

Few would deny that Arecibo Observatory is home to the world's most iconic radio telescope, star of Goldeneye and Contact (Pierce Brosnan... ? Jodie Foster ? Who ?). Even fewer would deny that Arecibo is 50 years old, because this is a fact. This magnificent facility suffers, however, from a surfeit of names, being variously described as "Arecibo Observatory"*, "El radar"**, and, just to annoy the heck out of everyone, the "National Astronomy and Ionosphere Center"***.

* What nearly everyone calls it.
** The local name. Would a letter sent (from within Puerto Rico) to the address "El radar" get there ? "Yes" was the unhesitating and unflinching response from a senior staff member.
*** The name the lawyers use, and the website too.



These days the telescope itself is known as the William E. Gordon telescope, after its designer. Who, incidentally, made an almighty factor-of-ten slip in his calculations, and that's why a small island in the Caribbean ended up with a 300m telescope and not just another forgettable 30m antenna.

I'm not even going to attempt to do justice to either William Gordon or the telescope. About the telescope I will only saw that its list of accomplishments is by anyone's standards impressive. It measured the rotation rate of Mercury, discovered the first binary pulsar, the first exoplanets, has sent messages to aliens, measured the distance to numerous potentially hazardous Earth-crossing asteroids, and done a bunch of atmospheric work I don't understand but I assume is important.

About William E Gordon, I will only point out that (I'm told) he was more usually known as Bill, so really we should be calling it Bill's Big Dish. My suggestion that honour the Observatory's instigator by painting some suitable tribute in big letters on the dish somehow never got taken up. Can't imagine why.

It would be a talking point if nothing else.
Anyway, Arecibo is, as I mentioned, 50 years old - the same age as Dr Who (coincidence ?). I was asked to create a short animation to be shown in the background for the resulting, "hooray, we're still here !" celebration. Fortunately, I already have my computer model (which was used to produce a laser-etched glass cube you can buy in the visitor center for $80). What I really wanted to do was include something like this...

Thanks, NRAO !

... which is a wonderful image of the NRAO Green Bank facility with the sky shown as if the viewer could somehow see at 4.85 GHz. So I wanted to do something similar for Arecibo, but using (obviously) Arecibo data.

For this I was graciously allowed to use data from the GALFACTS survey, which covers a huge chunk of the sky (the image I have spans about 85 x 17 degrees). Arecibo can't see all of the sky, because it's pretty hard to move a 300m dish. So it can only see a (still pretty respectable) swathe, but Bill's bloody big dish makes up for it by being ridiculously sensitive. Here's what it would look like if we could see GALFACTS data (after the experts corrected me for having it the wrong way round) :


The forest is looking decidedly deciduous for a tropical island.
But having a computer model means I can do a lot more than make a static image (though having moved from Arecibo to Prague recently does rather slow things down somewhat). I opted to ape the award-winning opening credits from one of the best shows on TV at the moment...

Game of Scopes
A Song of High Humidity Levels and the Occasional Hurricane
The fact that the inspiration for this image missed out Arecibo is a source of continuing disgust to me.

Anyway, here's the resulting final animation. Somewhat crude - no vegetation at all because it took too long to render - but quite serviceable, I think.


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