Choosing Instruments for the Thirty Meter Telescope

There is a very important meeting happening in Pasadena, California next week. That is when the Science Advisory Committee of the Thirty Meter Telescope (TMT) will decide on the first instruments for the TMT.

The TMT is a project that brings together the Caltech Institute of Technology, the University of California, the general US community through AURA and Canada through ACURA. Caltech and UC are the people that built the Keck telescopes. Each of these four partners have an equal share in the project, which means that Canada will have 25% of the telescope time on this behemoth when it is completed in 2015.

While the aperture of the telescope determines its light gathering power (size does matter!), it is the instruments that provide the astronomers with data they can analyse and solve the mysteries of the Universe.

So how do you go about choosing instruments for the world's largest telescope? The process starts with defining the science requirements of the telescope, i.e., how well the telescope will perform in terms of image sharpness, etc. Then the astronomers decide on what the big science questions will be 10 - 15 years ahead and what instruments will be needed to address these questions. Of course, trying to predict the big science questions that far in advance is a little like reading a crystal ball but it does set challenging requirements for the instruments. Once a suite of instruments have been sketched out they are ranked in terms of their priority and the top several are developed into conceptual designs. At this stage, you know a lot better how well the instrument will perform and how much it is likely to cost. Of course it costs a few $100,000 to get to this point.

Now with all this information in hand the SAC will make recommendations for the first instruments for the TMT.