For those who don’t know him, Artie Aardvark is my little friend who is very curious and likes to visit various astronomy sites. Naturally when he heard about the La Palma observing run, he was begging to go…
I am so excited, I get to visit La Palma and see what astronomers do! La Palma is an island in the Canary Islands off the coast of Morocco where a lot of Europeans come for vacation, and here I am relaxing with them on the beach a little before heading up to the observatory on the summit. I am worried though- it’s cloudy! Won’t the clouds make observing stars hard?
There are a lot of telescopes on La Palma! First we start with the Isaac Newton Telescope, the first telescope on the mountain brought over from England in 1979. I learned that astronomers refer to the size of the mirror when they talk about the size of a telescope, which for the Isaac Newton Telescope is 2.5 meters, or 100 inches.
Then I got to visit the 4.2 meter (160″) William Herschel Telescope that has been in use since 1987, and looks like the Isaac Newton telescope’s big brother. They also still have a really cool old control panel!
And I even got to visit the Gran Telescopio Canarias (GTC), which isn’t just the biggest telescope on La Palma, or the biggest telescope in the Canaries- it’s the biggest telescope in the world! Wow! The mirror here is actually made up of not one big mirror like most telescopes are but instead of 36 smaller pieces that make up a segmented mirror. These pieces then work together with what’s called adaptive optics to change their shape precisely in light of things like the temperature and the wind to keep it in a perfect shape, so it’s like a 10.4m (409″) mirror.
While at the GTC I even get to see the telescope spin around once- it floats on a pool of oil meaning it’s so easy to move a few astronomers can push it if they want, though probably not the best idea to do in real life. It is amazing to see the world’s biggest of anything, let alone such a modern telescope where all the parts work together so well!
After looking at all the telescopes that work during the nighttime, I also get to visit the Swedish Solar Telescope, which is the world’s biggest telescope for just looking at the sun. Looking at the sun is very different than looking at stars far away because even though it’s very close it’s also very hot, which can make the air around the telescope move like in a desert mirage. So what the solar astronomers do is put the telescope at the top of the tower- a 1 meter refracting telescope, meaning it’s a giant lens instead of a mirror- and most of the tower is a vacuum with no air in it so there’s no air to heat up in the first place. An astronomer showed me the entire the path the light takes, from the lens to the adaptive optics table in the tower’s basement, and I thought it was very clever!
In fact, I thought it was so interesting the the solar astronomers let me help with observations! This is the control room in the basement, where the pictures of the sun would update once a second. The solar astronomers could see details on the Sun’s surface as tiny as the island of La Palma, which sounded impressive to me but they assured me was “not nearly enough.” I guess things look different when you’re looking with more experience than just the untrained eye of an aardvark…
But La Palma wasn’t all just beach and telescope tours- I was also here to work! Yvette brought me to help as part of a course she was TAing, where students from the Amsterdam M.Sc. program partnered with the M.Sc. students in Leuven, Belgium to write proposals and use Leuven’s 1.2 meter Mercator telescope to observe for their projects. So I really got to learn what astronomers do, like airing the telescope at night to make the temperature inside as close to the temperature outside as possible, or to taking images of the sky at sunset before stars come out for “flat fields” you can subtract from the real data for better quality…
And then, of course, there was the observing itself! I was a little nervous, because as you can see there was a lot to pay attention to! It’s not really as scary as it looks, though, because most of the Mercator telescope’s observations are very automatic and a lot of it runs itself these days. We were also very lucky because October usually isn’t the best time of year for observing, but we had seven clear nights in a row while we were there! This meant we had to be at the telescope from 7:30pm to 8:30am when observing- though most people went to the astronomers’ residence earlier if they weren’t on the morning shift.
All in all, I learned a lot about astronomy and hope my new friends get good results from all the great data we took! And I think if heaven is above the clouds, well, with all the telescopes and things to see and do La Palma is an astronomers’ heaven for sure!