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



Monday, 25 July 2011

I Miss Civilization

Unfortunately, I'm not referring to the excellent game series by Sid Meiers, although that was very good. No, I'm referring to the little niceties that citizens of the First World are apt to take for granted, like reliable electricity, water, a sensible climate and a whole plethora of alcoholic beverages. Such is the downside of trips to the States, even if the place is weird in its own way.

I don't particularly care to detail most of my exploits in Green Bank to the world at large, save that they involved some very un-me like behaviour, a replica of Karl Jansky's radio telescope and a locked pool. Ahem. Anyway. Here's a picture of the Ewen and Purcell feed horn, the first instrument to ever detect HI emission. I certainly have absolutely no idea that at least 6 people can comfortably drink inside it.


The above is the actual feed horn. The Jansky is only a replica, but it comes fully equipped with the ability to rotate if a few astronomers get off and push, but I definitely don't know anything about that at all. The less said about this one the better for all concerned. At least in public. Snigger, snigger...


This particular observatory is, ironically, situated even further away from reality than most others. Normally, it's a 4 hour drive to Washington, and when the place is bombarded by 50+ students and staff astronomers the place is further still from anything approaching normality, especially given the presence of a seemingly bottomless drinks cabinet.

Not that this impeded scientific progress in any way whatsoever. No sir ! When there weren't lectures or drinking there were tours of the telescope. And though I shall be able to say "ours is bigger !" without fear of reprisal for the next 5 years at least, it's still impressive. After all, it's 100m wide and one of the largest steerable dishes in the world. It is also a good viewing platform.




Credit where credit is due - these guys have a way more impressive control room than us. They also don't feel the need to cool it to a sub-arctic climate, which is nice. On the other hand, no-one has ever made a movie in which Green Bank scientists try to take over the world or discover aliens, so we must be doing something right.


As a responsible post-doc, my main reason to attend was to supervise hands-on projects, a phrase I can no longer use with a straight face, so I won't. Ahem. I seem to be developing a nasty cough. Anywho, when I wasn't fetching my students beer, I was doing my patriotic duty and educating the world that Wales, contrary to popular belief, in fact owns both Green Bank and Arecibo. It's remarkable that this is so often overlooked by the media.



And finally, I genuinely have no idea what this thing is. No-one does. It appears to be a segment of a radio telescope, but how it got there is a mystery. Not a single staff scientist knew the answer. If it is signposted at all, it most certainly doesn't simply say, "DANGER DO NOT CLIMB", and I for one haven't got a clue what type of clothing enables the fastest sliding down this mysterious artefact.

Thursday, 7 July 2011

What the Tourists Don't See (III) : The Platform

At long last I found an excuse to get up to the platform, which means I can bring these little behind-the-scenes excursions to an end. Well, nearly anyway. There may or may not be a trip to the lidar lab in the near future, but I don't know if that will involve pretty pictures or not, and that's what we've all come to see, right ?

Anywho, the platform. A 900 tonne construction suspended 120 metres above the dish, this is the business end of the telescope. James Bond decided to access it via the catwalk, but if he was less pushed for time he could have taken the cable car instead. Not much scope for dramatic chase scenes there though, especially as there's only one car.



On this occasion however I did take the catwalk, and while no epic battles ensued there was dancing involved. All with be revealed, but not today. Like the cable car, the floor is a metal mesh consisting mainly of holes, and unlike the cable car the side walls are unnervingly flexible. However, this is surely an improvement from an earlier incarnation of the catwalk, which I'm told was a proper Indiana Jones affair with a wooden floor.



Both car and walkway lead to the very top of the platform which, weirdly, is absolutely rock solid. It has to be, otherwise the thing wouldn't work. Running between two support structures is a large metal cable which when struck makes a sound that's pretty near identical to any science fiction laser blast you've ever heard.

She hasn't gone mad. She's just listening to the cable, as you do.

I don't remember what the platform in Goldeneye looks like but I think most of it was filmed there so it should by rights be pretty similar, unlike the control room. However, I once again spotted no evil villains bent on global destruction, just some astronomers with a real talent for pulling peculiar expressions the instant a camera is trained on them. It's uncanny. Perhaps I just kept interrupting their evil scheming, but if these guy's are the biggest threat to international security then we can all rest easy.



Stairs from the uppermost level lead down into the very centre of the structure. To reach the lower levels you have to climb backwards down some very narrow stairs, which are built around the central axis about which the whole thing rotates. It's exactly like descending into the web of some ferociously over-complicated bio-mechanical spider that's developed a curious interest in radio astronomy.



Telephones can be found just about everywhere, including this one which looks like it's older than time itself. It's about one step up from a carrier pigeon, I reckon. Of course, all the electronics are chosen so they don't generate RFI, but surely this is pushing it.



Next comes a trip along the hugely complicated azimuth arm, which supports the instruments. This has the same centre of curvature as the dish and the instruments can move back and forth along it to change their angle of elevation. It's all extremely primitive-looking, covered in cables and maintenance workers for whom galavanting around a hundred metres in the air is just a day job.



The main difference between the platform today and when they filmed the Bond movie is the addition of the giant Gregorian Dome. This is where all the really cool receivers hang out. The line feed - the thing what Sean Bean fell off - is still there, but nowadays all the neat stuff is inside. Two more mirrors focus the signal from the main dish to a point. One of these is 25 metres across and is just too big to photograph properly, so here's a short video clip. Note the resemblance to the Death Star.

video


And so we come to the receiver room itself, featuring the one and only ALFA instrument that's kept me in employment for the best part of 5 years, a truly scary thought.


Not many people know that ALFA is controlled by a small fluffy kangaroo without whom the entire telescope would surely collapse into a great heap of rubble. This is because it isn't true, but there is a small fluffy kangaroo securely fastened to the instrument with a cable tie. His name is Hep. Or Hap. Or maybe it was Pap ? Or Pep ? I couldn't tell, on account of the very noisy air conditioning units.


Which I suppose brings me to the end of this final tour, since going down is remarkably similar to going up but in reverse. I'll return next week with a report on the comings and goings of the NRAO Green Bank observatory, which features the world's largest fully steerable dish. Be there or be a rectangular thing !

Monday, 4 July 2011

Happy Loss of the Petty Colonies We Never Really Wanted Day !

It's 4th July, and to my delight, Astronomy Picture of the Day has declared the existence of the Southern Ocean. Huzzah ! Congratulations, America, all is forgiven. I think I'll celebrate with a nice cup of tea and an episode of Sharpe on blu-ray. That's a very American thing to do, right ?

Independence Day must be very confusing for Puerto Ricans. After all, it was captured from Spain by the Americans in 1898. Not until 1947 were Puerto Ricans given the right to elect their own governor. How then, does this tiny island react on such an occasion ? As far as I can tell, by having a damn good clean. That's what my street appears to be doing anyway. The only other difference is a tenfold increase in the number of extremely obnoxious quad bikes.

On an unrelated note, it's well-known that Americans can't spell, preferring as they do to more often than not omit the "u" from most words, thereby making the spelling more logical, intuitive and wholly wrong. For some reason metallurgy offers particularly strange examples. First, they insist on "aluminum" but at least they have the decency to spell it the way they mispronounce it.

Secondly, and much more bizarrely, Americans can't do soldering. Oh, sure, they spell solder, but pronounce it sodder, which is just baffling. I've never heard of a soddering iron before, but it sounds damn dodgy to me. Good thing I'm not an engineer or I could be in real trouble. Being paid for soddering is surely illegal and likely to get you stoned to death in certain less inclusive countries.

I'll never look at this in the same way again...

Sunday, 3 July 2011

CG project : viewing FITS files in Blender

Warning : this post may contain or allude to content of a scientific nature.


Any technology that is sufficiently advanced is indistinguishable from magic, and any technology that is indistinguishable from magic is sufficiently advanced. However, there's another, lesser-known part of this maxim, which is that any technology capable of viewing FITS files is also sufficiently advanced and therefore magical.

What the hell am I blathering about ? Well I have this crazy notion that if data is 3-dimensional, then it should be viewed in 3-dimensions. Neutral hydrogen - HI to its friends - data is a good example, because the data records both position on the sky and recessional velocity (which is a half-decent proxy for distance away from us). Such data is recorded in a Flexible Image Transport System files. What does not currently exist - as far as I'm aware - is a good way of looking at such files in 3D in realtime. Instead, we're reduced to panning through data cubes one slice at a time.

I'm not convinced that this needs to be the case. To that end, I've written a series of IDL and Python programs to import FITS files into Blender. Actually viewing the files in Blender is the easy part. The difficult bit is cleaning the files enough so that Blender can handle them. This is probably more a software than a hardware issue - Blender isn't optimised to handle thousands of different objects and materials, let alone the tens of millions that make up most data files. So for now, this specialised project is only of use in even more specialised cases where most of the data is noise and can be rejected.

However, for those cases where it does work, it works extremely well. Here is the famous "dark galaxy" VIRGOHI21 rendered in Blender, in realtime. It probably could use a minimalist new-age soundtrack, but never mind.



Friday, 1 July 2011

Oh no !

DAMN YOU GOOGLE !!!


A hex upon thee ! May you die screaming from the Ebola virus and your children be thrown into the Pit of Sarlacc ! I'm gonna break your house, burn your legs down, rape your pets and kill your women and not necessarily in that order !

...

Ahem.

...

The astute reader may note that Google has started their umpteenth attempt at a rival service to that dark Satanic rumour-mill that is Facebook. Except that this time it appears that they really mean it, and when Google puts effort into something it usually wins. OK, so Buzz wasn't anything more sophisticated than having an extra email folder, but that's just an example of Google doing something out of boredom. Of Wave I have no knowledge, save that it existed for a little while and didn't do anything.

The problem is that I'd sooner devour the kittens of the previous post than sign up for Facebook. But the problem with Google is that sooner or later this "plus" thingy will be given to every Gmail user whether they want it or not, as is the way of Google's well-intentioned tyranny. So I've gone and joined it anyway, although whether I stay on it is currently a decision resting on the edge of a knife. It certainly is an easy and convenient way to share stuff with select people...

Aaargh ! Don't do this to me Google ! Why must you implement the very thing I despise most ? Can't we all just go back to writing letters ? Or carrier pigeons, how about them ? Couldn't have the social horrors of status updates and Farmville in a network run by pigeons...


And now I've no choice but to upload some more photos and then drink myself into a stupor to ease the pain.