how to drive a telescope 1
One of the many screens to which a telescope operator must refer constantly as he drives the telescope.

How to drive a telescope

While watching John Hill operate the telescope last night, I asked about some of the many things he has to keep track of as he drives the ‘scope. I enquired about one of the screens in the control room one of which featured a disk of dots and found out that these are sensors which indicate infinitesimally tiny changes to the telescope’s main mirrors, which result in astigmatisms or ‘corn flaking’ of the mirror surface. These sensors not only detect the changes, they correct for them to within the millionth of the breadth of a hair. John points out that when things are going well, there isn’t a lot to do but there are lots of things to keep track of constantly. For instance, if the wind starts blowing strongly, the telescope doors should be shut. If cloud cover is approaching, the astronomers need to be warned that their observing will be curtailed. Atmospheric changes also must be monitored. During laser commissioning, the mountain was alive with plane spotters warning of approaching flights. This is a function that the LBT hopes will be automated soon.

Astronomer’s confessions

In chatting with Sirio, Italian astronomer in a very good mood (observations have been spectacularly good over the past few nights) I learned that not all spectrometers are built along the same lines. In other words, if you are a bus driver and you decide you are going to drive a bus for another bus company, it is still a bus and you are qualified to drive it. In the case of astronomers, whose universities have paid for thousands of dollars of observing time on a specific telescope on a specific night, these astronomers must use this pre-paid time well. And in order to use the time well (barring weather, which is not controllable) these astronomers must know how to use the spectrometers and interferometers and other instrumentation correctly. The telescope operator can drive the telescope and focus on whatever the astronomers choose but they must give the operator the correct type of guide star for the instrumentation they are using. “Each spectrometer is a custom design and might have, externally, very little in common with any other instrument with the same name,” points out Sirio. So the astronomers, who are not trained engineers, must ‘learn’ this instrumentation ahead of time and it can take a week or more of intense study to nail a particular instrument. It is comparable to finding out that your new car has the steering wheel located somewhere in the trunk.

I told Sirio about my conversation with Father Christopher Corbally of the Jesuits at the Vatican Advanced Technology Telescope (next to the LBT on this mountain), who has produced an academic paper on the truth about lambda bootis stars. About forty years ago, some prominent astronomers decided to throw these confusing stars into a ‘garbage bag’ of unknowns and wait for someone to sort them out. The initial sorting had these stars designated as ‘twins’ or two stars masquerading as one. Father Corbally and his colleagues were able to produce proof that the stars were not twins and also point out that they do not fit comfortably into the current classification system — they are enigmas. Sirio told me that this was a hot new area of astronomy — going back over archives and challenging assumptions and combining that knowledge with new findings.

Today I have been told that the engineering team on the Linc Nirvana system needs a break and they are interested in creative break exercises. We had a lot of fun doing cyanotype print making and texture mapping yesterday with Telescope Manager, Mike Wagner. Hope I have enough operational brain cells after three days at altitude to do a decent job on the instruction!