For the last month, one of the major projects on the telescope has been measuring the surface of the 10-meter reflector and adjusting it carefully to create a very accurate surface. This entire project has largely been the job of Chicago postdoc Jeff McMahon, who finally left to go home for the holidays after a long and intense effort to perfect our telescope dish. While my work has not overlapped much with what Jeff has been up to, once in a while I am useful for odd tasks. About a week ago, Jeff realized that he needed a series of big black stickers removed from the surface of the telescope reflector. These were placed there as “targets” for special photographic measurements last season, which helped us to create an accurate surface for the first observations. The stickers weren’t a big problem for our regular observations, so we just left them there rather than risk someone walking around on the dish to remove them.

The surface of the reflector itself is made up of many individual aluminum panels that are set by hand (basically by adjusting about a thousand individual screws) so that the total surface has a shape that is perfect to within the thickness of a human hair. It is really an impressive thing! It does not necessarily look as perfect and beautiful to the human eye as it does to the microwaves it is designed to reflect, so you have to use your imagination a little when you look at the pictures. The reflector has lots of marks from stickers and tape that we have used for various iterations on measuring and adjusting the surface. Jeff’s measurements had reached a level of accuracy such that the largest of these stickers simply had to go. As the lightest member of the team, it made some sense for me to perform this slightly unnerving operation of crawling around the dish to peel them all off.

My precarious perch atop the reflector.

The task was actually a lot more difficult than I expected. I tried to dress somewhat lightly so that I wouldn’t be bogged down and could move around carefully and comfortably. But consequently, I was freezing cold. We got me up into the dish with the telescope resting on its back (I won’t describe how but again, use your imagination). I had to crawl around on two foam pads, carefully distributing my weight across as many panels as possible each time I moved. Inside, the surface of the mirror is actually quite steep and any kind of motion required a lot of care to avoid sliding, falling, or dropping gloves or tools into the center. As I moved around the dish I had to pry off each sticker and remove all of the adhesives and tape used to fix it in place. There was no way to do this effectively with gloves or my glasses, which fogged up uselessly, so it was surprisingly difficult for such a simple task. The whole operation took a couple of hours and I was really feeling the cold by the end of that. But it was definitely a unique experience I will never forget–how many people get to climb around inside a gigantic telescope, at the South Pole no less? I was also relieved to find out later that my telescope traverse did not alter the overall shape of the dish to within the accuracy of Jeff’s measurements. Phew!

Waving from the giant telescope.

Jeff took some pictures while he was standing outside, making sure that everything was going OK. That’s me waving. All that plywood you can see on the telescope boom was also part of Jeff’s project to measure the dish more accurately, and now that his instruments are all packed up we will put the normal roof back on.