In April I managed to persuade my supervisors that I needed to return to La Palma to get training on how to use ULTRACAM (the big brother of ULTRASPEC). The ultimate aim, I think, is for me to become one of the core team members who can go out and use it as an ‘expert’, without the need of one of the other team members to be present. This is quite exciting, as there is talk of the instrument being shipped to Chile for use at the NTT next time round, rather than at the WHT where it is currently. Anyway, I recently spent a week on the lovely Isla Bonita, which I still consider to be my third home.
I’ll save the best bits for the middle, and start with the worst part of the trip. This was undoubtedly the travel to and from the island. Being one of the smaller, less populated, and less touristic islands, La Palma has very few direct flights from outside of Spain. Even though I wasn’t paying for it myself, I was still trying to spend as little of my travel budget as possible, so I’d booked Ryanair (world’s worst airline) flights to Gran Canaria, and connecting inter-island flights with Binter Canarias (world’s best airline). Sadly, all of my flights on the way out were delayed (some by up to an hour), which added an unwanted level of stress to the already stressful event. Travelling with Ryanair isn’t fun at the best of times, but when the flight is an hour late, the staff are keen to get everyone sat down even more swiftly than usual. This, coupled with everyone else on the flight’s absolutely and uncompromising need to sit with their children/partner/friends makes for a bad start. To be fair though, the rest of the flight was bearable, and the return trip wasn’t too bad at all. I even got a breakfast donut on the first Binter flight on the way home – win!
My first evening back on La Palma was spent in true traditional style – eating pizza at Mamma Mia’s pizzeria. And boy had I missed those pizzas! I’d happily eat there every night if it was so unhealthy… oh yeah, and 2500km away. Anyway, it was really great to catch up with old friends on the island, and the following day I was up early to go diving.
Having not been underwater in 9 months, I was a little nervous about my abilities. Because of this, I turned down the opportunity to join the divers heading for the small, shallow cave just south of Los Cancajos, and instead went through El Cañon with Ricardo. I really shouldn’t have worried though, as I felt right at home within seconds of being in the water. So, whilst I was perhaps a little disappointed to not be exploring a cave, it was still brilliant just to be back in the warm, clear water with a good friend. Sadly I could only fit in one, shallow dive that morning, as I had to be up at the observatory in the evening, and didn’t want to risk any difficulties with decompression. Luckily though, I managed to arrange to have one more full day at sea-level after the 5 nights on the mountain, and squeezed in another two dives. These were from El Faro de Fuencaliente in the south (one to La Torreta and one to Las Cruces) and both were excellent dives. My diving spirit has definitely been rekindled, and now I can’t wait for the illusive trip to Thailand, where I hope to fit in some more warm water diving.
After one night’s sleep at the Residencia of the observatory, it was straight to work at 9:30am. The task for the day was to mount and test ULTRACAM, whilst learning how to mount and test ULTRACAM, and simultaneously taking photos and writing a guide on how to mount and test ULTRACAM.
This all went rather well, and the day went quickly. There were no major problems (such situations are almost unheard of in observational astronomy!), and there was even time for a shower before the ‘real’ work began.
As the sun began to set, it was time to embark on some real astronomy – searching for the secondary eclipse of a transiting exoplanet. This is when the planet passes behind its host star, which shadows any light reflected off the planet’s atmosphere. Even for faint stars and massive, very shiny planets, this change in measured light is as little as 0.1%, which is very hard to see. In the rough data reductions of the three nights of data we collected for these systems, we could see no obvious signs of an eclipse. This in itself is not entirely useless though, as it allows the team (based in Leiden, the Netherlands) to put tight constraints on just how bright/reflective the planet is, which in turn can be used to try to understand what the atmosphere of the planet is made of.
On my 5th and final night at the telescope we were observing the transits of other exoplanet candidates from the Kepler survey. Utilising ULTRACAM’s three-colour system, Stu will be able to determine if any of the candidates are in fact grazing eclipsing binary systems, rather than transiting planets. If the transit depths are different in different colours (essentially red, green or blue), this would suggest than the system is actually an eclipsing binary system, where the two stars involved have significantly different surface colours, but their eclipse paths are not fully aligned with our line of sight. Instead, only a small fraction of the light from one of the stars is blocked, in a grazing eclipse. This would cause a small eclipse depth, as seen in exoplanet transits, without there necessarily being a planet present.
As well as doing ‘real science’ with the WHT (although I must add, I was simply watching and learning, most of the time), Stu and I also spent some time working with the pt5m. As well we faffed around with the Python coding (most of which was written by Stu anyway) that we’re now using to automatically reduce data from transient observations taken with the pt5m, and submit the results to the GAIA Science Alerts server. Of course, when you’re only observing one or two targets over the course of an entire night, and there’s 5 people on hand to keep an eye on things, there is still plenty of time to watch cartoons 😉
Overall I really enjoyed the return visit to La Palma, and it was great to catch up with old friends. I just wish I could have spent more time both at the observatory and at sea level! Within 24 hours of landing back in the UK I was setting up my tent at Latitude Festival for another week of hard work and baking hot sunshine. It was certainly tough moving quickly from working the night shift to working the 10-16 hour day (and night!) shifts, but it was great to be back at my favourite big festival again, and I’m already looking forward to next year.