At the Las Campanas Observatory, in the Atacama Desert, in Chile, they are building one of the so-called "Estremely Large Telescopes", the Giant Magellan Telescope (GMT) with a 24.5m diameter primary mirror, which should in principle be ready in 2022. Its name is a tribute to the Portuguese navigator and explorer whose expedition discovered the passage between the Atlantic and Pacific Oceans, and ended up making the first circumnavegation of the world. The GMT, part of an international consortium led by the United States -Giant Magellan Telescope Organization (GMTO)-, will also revolutionize our vision and understanding of the Universe with Astronomy from the Southern Hemisphere. The person in charge of the Active and Adaptive Optics on this telescope is Antonin Bouchez, Head of the Wavefront Sensing and Control Group on the GMT team, and expert in Planetary Science and participant in the conference on "Adaptive Optics for Extremely Large Telescopes" (AO4ELT5), which has taken place this week at the Hotel Botánico in Puerto de la Cruz, Tenerife, organized by the Instituto de Astrofísica de Canarias (IAC).
By Elena Mora (IAC)
GMT has a deformable mirror built inside the telescope so is a fully adapted telescope.
This interaction between engineers and astronomers is very valuable.
Even though we are all working on similar problems between the three giant telescope projects, this is a good opportunity to work together and share ideas.
Question: Could you briefly explain the Adaptive Optics (AO) systems currently being designed for the GMT?
Answer: Similar to the European ELT, GMT has a deformable mirror built inside the telescope so is a fully adapted telescope –in our case it is the secondary mirror-. We have a 24 m primary mirror, a segmented 3 m secondary mirror, which is adaptive and can correct the atmosphere at high speed. All our instruments use the AO in one way or another, either by correcting the ground layer turbulence for short of wide field correction or by correcting the entire atmosphere to reach the diffraction limit.
Q: At present, it is more difficult to apply Adaptive Optics in the visible range than in the infrared. What could be more interesting to develop: AO for infrared extremely large telescopes or AO for optical 10 m telescopes?
A: They are both very challenging. They both push the limits of technology, either correcting a short wavelength on smaller telescopes or longer wavelengths on larger telescopes. For the last, I think there are more unknowns so I find that more interesting because, to some degree, we don’t know the problems we are going to have when we develop this systems so that’s why I enjoy it, I guess. Uncovering problems while we are developing future instrumentation for current telescopes I think we understand the problems better, even though it is still very challenging.
Q: What is your impression about the meeting? Do you think the interaction between engineers and astronomers is more necessary than ever?
A: This is very valuable. In fact, I think some of the most interesting talks have been from the engineering side although for me the most interesting talks here are the astronomy talks describing the limitations to current research and then trying to find solutions to them. Conferences like this are really a great chance to tackle these problems. Also, I think it is very important for collaboration between the projects, even though we are all working on similar problems between the three giant telescope projects, this is a good opportunity to work together and share ideas.