Mt John Spectrograph Testing

Hello all - Steve here. Thought I'd share some of the pictures I took while at Mt John for three weeks in April testing out the new spectrograph.

Since Mt John is on the South Island (at a town called Lake Tekapo), we packed the spectrograph up in a van to take it to the observatory. AK joined me for trip, which involved taking the 3hr long Cook Strait ferry between the two islands. Here's a picture of AK on the ferry with the rental van - with the spectrograph and all its required bits strapped down securely for the trip.

Luckily the seas were calm that day, and we were also able to see a few dolphins playing in the ferry's wake. After arriving on the South Island, it took us about 11 hours of driving to reach Lake Tekapo. Normally we would have been staying at the observatory itself, but since they were renovating the accommodation building we stayed in the town at a holiday home. My advisor Stuart met us in Lake Tekapo, and he stayed for the full two weeks of testing (AK stayed for a few days then flew back to Wellington). The house had a great view of the lake and mountains from the front deck, and it was nice to see some of the trees displaying fall colours.

The following day Stuart and I rounded up a few guys to help lift the spectrograph out of the van. I had taken all of the optics and delicate parts off the table for the trip, but the table still weighed several hundred pounds and took 5-6 people to lift it out of the van!

While Stuart and I started unpacking and putting the spectrograph back together, AK took the van and did some exploring around Mt John. Here's a picture of Mt John and the observatory (little white dots on top of the hill) from 'ground level'.

And here's one of Lake Alexandrina (a small lake next to Lake Tekapo).

At one point she had to stop so that a herd of sheep could cross the road:

We had a couple of days to get set up, and then on our first scheduled night on the telescope we had our official 'first light' - we took a spectrum of a star named Antares.

In this spectrum, you can think of each line as a range of wavelengths (or colours), with blue at the top, red at the bottom, and the other colours of the rainbow in between. Antares is a very red star, which is why the top (or blue) lines aren't as bright as the red ones at the bottom. Unfortunately our camera only takes black and white images so you can't see the colours directly (colour digital cameras aren't as sensitive as black and white ones so they're not used as much in astronomy).

Although it may not look that exciting, by studying the dark notches within the brighter lines, one can tell what the star is made of, how fast it is moving through space, whether or not it has a companion star with it, or whether or not it has a planet around it. For example, on the fifth line from the bottom, on the left of center there are two broad dark notches. Those two 'absorption lines' show that Antares has sodium in its atmosphere.

After we had the spectrograph up and running, we spent the next two weeks taking hundreds of spectra of many different stars. Stuart and I would start work around 4pm and head home around 7am. As well as taking spectra, we also spent some time making small changes and improvements - here's a picture of me making up some temperature sensors at about 3am one night:

One advantage of working nights was the spectacular sunrises. Here are a couple pictures of them:

A few days before the end of our testing run, AK's Dad Mark flew down to meet up with me and help with the long drive back. It was a good chance for him to see a bit of the South Island, and I definitely appreciated having some company on the trip home.

So, overall it was a very successful trip - the spectrograph worked great and actually performed better than we had hoped for a first trial run. We have another two weeks booked on the telescope in July, so I'll be kept busy until then analyzing all of our data from this trip and making some small changes to the spectrograph for the next one (not to mention the arrival of our little one sometime in the next few weeks!)

Here's one last picture of the moon and the 1 metre telescope we were using.