Saturday, April 6, 2013

Astronomy: Observing at Las Campanas

Las Campanas Observatory

A few weeks ago, I went up to Las Campanas Observatory to observe with the du Pont 2.5-meter telescope. I had only a single night, but this blog post recounts my experience there.

From the get-go, you can tell that Las Campanas is run differently from La Silla. At La Silla, they book your flight and you arrive at the time they designate to take one of the limited vans/buses up to the mountain. Here, you tell them when you'll arrive and they'll have someone waiting to take you up, even if you are the only person for the trip.
The observatory is also far nicer looking. The buildings are more rustic and blend into the surrounding mountainside.

View of the 6.5-meter Magellan telescopes from the dormitory and dining hall complex.

There is a more casual atmosphere at Las Campanas, which unfortunately means newcomers like me can feel a little lost. At La Silla, you know exactly when and where you are supposed to meet up with your instrument specialist. Here, things are more laid back and relaxed. I was worried, but fortunately everything worked out. In the end, observatories are all run in a similar fashion so once you've been to one you have an idea what to expect in most occasions.

Las Campanas was very crowded when I was there. First, there was a large engineering group working on the new Adaptive Optics systems at Magellan: MagAO. Second, there was actually a special event going on. Lots of Very Important People had arrived and were being shown around. We had a fancy dinner and a BBQ the following day so we ate well. During dinner, I actually sat next to the ex-CEO and chairman of Intel, which is pretty cool.

The du Pont 2.5-meter telescope

I was observing at the du Pont 2.5-meter telescope, which is one of the older telescopes on the mountain (in operation since 1977). It's also the farthest from the dorms so it takes about a 30 minute walk to go from one to the other. You can also borrow a car, but these are manual transmission which I've yet to learn how to operate. Unlike at La Silla, you actually go up to the telescope to observe.

Inside the dome of the 2.5-meter du Pont telescope

I was set to use the B&C spectrograph, which is an instrument that splits the light from the star by its wavelength into what we call a spectrum (see below).
The instrument was far simpler to use than I had feared. The manual provided very little information and I was worried how well I could use it. I did contact some of the staff and that was the greatest source of help. The resident astronomer was there for a few hours in the afternoon and evening and helped me set up. Once I got a chance to use it, everything worked great.

Spectrum of a young, low-mass star.
The spike at 6563 angstroms is emission from Hydrogen in the atmosphere of the star.

I've yet to fully process all the data, but above you can see a spectrum of a known young (~10 Myr), low-mass star. It serves as a comparison so I can see how good the instrument is. For the astronomers out there, this was taken with the 600 lines/mm grating set at an angle of 13.5 degrees and using the 100 micron (~1") slit. While decent enough, I think I may opt for the 832 lines/mm grating in my next run.

Overall, I liked Las Campanas and the telescope+instrument combination I used. I have more time in the coming months so I hope to get to know it better and get some good science out of my time there.

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