A couple of weeks ago I started asking my friends if they might want to write a guest post for my blog, quite a few of them have piped up wanting to write about their speciality subjects, favourite things and other random shit. The first post comes from Dave, an optical astronomer, who has written about his observing travels to South Africa. Enjoy!

Hi, my name is Dave and I’m an astronomer. Recently, Kim sent out the call for people to provide guest posts for her blog, I said “Sure, sounds like fun” without any real idea of what to write about. “Stick to what you know”, that’s what they say, so what do I know? I’d like to think I know lots about lots, but that’s probably pretty wide of the mark, so I’ll stick to astronomy (something I should know something about). Now, what about astronomy? Some of it is dull as fuck, if you’ll excuse the language (if you won’t, then fuck you twice in the eye). How about an observer’s diary? A sort of “Week in the life of a telescope-using astronomer”, maybe that might be of interest to people who for one reason or another have no idea what we astronomers do (I can’t take credit for this idea, it was originally an idea Adam had for the Jodcast that never came to fruition). Here goes:

Our story starts about three months ago when I submitted an application for time to use a telescope, in this case one near the town of Sutherland in South Africa (the coldest place in the country, apparently). Anyway, at regular intervals the organisations who control telescopes (different depending on which telescope) invite applications from the astronomical community, in which you have to detail what you want to use the telescope for, how many nights you need to do it and why it’s worth doing. These applications then go to a panel of senior astronomers called a Time Allocation Committee (or TAC) to decide how best to distribute the time available (seeing as there are only 365 days a year they can only divvy up 365 nights between all the astronomers applying to use their telescopes). On this particular occasion, I was lucky enough to be given a week (I asked for two).

Now, fast forward to the day I have to fly out. It’s a Sunday, my flight leaves Manchester airport in about 3 hours; I haven’t packed yet. I quickly throw some clothes in a case – plenty of layers, remember coldest place in South Africa – and call a taxi. Some hours later I’m sat in Heathrow reading the book I’ve brought with me to read on the plane (Things The Grandchildren Should Know the autobiography of Mark Oliver Everett of EELS – the chapter where his mam dies almost made me cry), while waiting for my delayed flight to Cape Town. Several hours later, I’m stuck in cattle class on an 11 hour flight next to an old woman I can best describe as scuffley. By now I’ve already finished the book I was intending to read on the flight, so I watch a few films: Fantastic Mr. Fox and An Education. One a kids film distinctly not for kids, the other a film with paedophyllic undertones that I find pretty discomforting. About 8:30am South African time, we land, I collect my bags and go to the guest house where I’ll spend one night before travelling to the observatory. Even though the Sun is shining and it’s a beautiful day, I go straight to bed (having not got any sleep on the flight). I surface again at about 6pm but only to feed. The following day, I set off on the transport to the Observatory which will take about 5 hours, providing yet more opportunity to catch up on sleep. I wake up about an hour before we get there and notice we pass a baboon at the side of the road. I laugh out loud at its giant red arse. This only serves to get me a few funny looks from my fellow passengers. When I arrive, I negotiate the change-over with one of my colleagues who has been observing for the past week. I will start late so I can watch the Bayern Munich – Manchester United match, and he can finish early so he can get a good night’s sleep before the 5 hour journey back to Cape Town. I win in the end, because shortly after he goes to bed the weather turns bad and forces us to give up and go to bed ourselves.

The telescope plateau and astronomers’ hostel of the South African Astronomical Observatory

Here is an appropriate time to get technical, so as the advert says “Here comes the science bit”. The observatory I’m at in South Africa is an optical observatory, meaning the telescopes are all designed to detect optical light (the stuff our eyes can see), other observatories are set up for other types of light (i.e. Parkes in Australia, where Adam has just come back from, is a radio observatory, meaning its geared up to detecting much longer wavelengths of light than optical). Observing at different wavelengths of light demand different conditions. Radio observatories, for example, can be pretty much anywhere as radio-waves pass straight through clouds, optical light on the other hand obviously can’t (our eyes can’t see any stars on a cloudy night!), so optical observatories have to be in places with the clearest and darkest night skies around. One of the ways astronomers measure the clarity of a sky is with a thing called seeing, which, for the sake of further clarity, I’m going to call twinkle-icity. You see, the twinkling of stars, is not something intrinsic to the stars themselves but as a result of us looking at them through the atmosphere (just like looking through a rippling pond). The best sites to observe from are those with the lowest twinkle-icity, or the places where the atmosphere has the least influence on what we’re looking at – giving us the clearest picture of what is happening in space. In practice, this means that the best observatories are in high and dry places, like Cerro Paranal (in Atacama Desert, Chile), at the top of Mauna Kea (in Hawaii) and the Roque de los Muchachos (in the Canary Islands, see picture).

Me at El Roque de Los Muchachos in La Palma, Canary Islands

Me with the Isaac Newton Telescope in La Palma, Canary Islands

Back to the “diary”. Having gone to bed early on the first night, I’m up at a spritely 2pm to have breakfast and take a little walk around. The Sun sets at around 7pm so at 6:30pm we’re back up at the telescope, opening the dome and preparing the camera for observing. It reality, the camera is nothing more than a very expensive, very sensitive, black-and-white digital camera stuck on the back of the telescope. Going back to the beginning, the project we proposed in our application was to look for undiscovered binary stars – two stars in close orbit around each other like the Earth and the Moon. These stars are so close together, that we actually can’t tell them apart, they just look like one star (partly because the twinkle-icity smears the two stars together, but mainly because it would be almost impossible to build a telescope big enough to see the gap between them), so we have to be clever about it. We find them by taking lots of pictures of the star (that we think might actually be two stars very close together) over an extended period of time and measure how bright the star is on every image. If there are two stars orbiting around each other, when one star passes in front of the other it will block out the light from that star (just like the Moon during a Solar eclipse) making it appear fainter than when the two are side by side. So, we draw a graph of star brightness versus time in the hope that we’ll see these dips in brightness (as one star passes in front of the other) at regular intervals corresponding to the amount of time it takes the stars to do a full orbit (see picture. Credit: Swinburne).

And, this is what we do for the next seven nights, 12 hours a night, in the coldest place in South Africa, sharing the control room with Steve the Light Scorpion (see picture). We monitor the brightness of several stars, in hope of detecting binaries. It can be tough and is always pretty exhausting. There probably aren’t many jobs where you are expected to work 12 hour night shifts, often alone, but people don’t do it because it’s a job – they do it because they love it (that’s why I do it, at least).

Steve the Light Scorpion

Dave Jones
Night 7 of 8 at the South African Astronomical Observatory

p.s. If this was at all interesting to anybody at all, maybe I could do a follow-up on why we’re looking for new binaries? It won’t be too boring, I promise, plus it’ll be crammed with astronomy pretty pictures!

So there ya go! I hope you learned something new, I did! mainly that Dave can go quite a while without cussing, who knew?! Thank you to Dave for the interesting insight into looking at twinkley stars, and scorpions. Do any of you have something you’d like to share? Please get in touch! I’d love to have some more posts like this on the blog :)