Untitled - Laboratoire d'Astrophysique de l'Observatoire de Grenoble

• Improving High Angular Resolution observation capabilities The goal is here to go beyond the
current limit (typically several milliarcsec at J to K with the VLTI), requiring kilometric baselines for
near-IR interferometry (providing down to 10 − 4 arcs) ; it can also be, operational constraints permitting,
to use (segments of) large single-dish telescopes (ELT-type, under completion phase) at visible wavelengths
by pupil masking techniques until AO systems can work at V on large telescopes. The related
developments are also to be found in progressing in integrated optics on one hand, in progressing on the
system optimization needed for combining AO use with pupil masking on the other hand.
10.2.3 The principles of our involvement
Our philosophy is based first on the acquired experience in Grenoble of course but also in other places :
high angular resolution techniques are complex and benefit must be taken from all the available experience
accumulated in the laboratory or on the sky. Our developments in integrated optics (such as the IONIC longterm
R&D) were tightly based on the anterior work on FLUOR at Observatoire de Paris while the design of a
large AO-based instrument (like NAOS) was based on the successful approach followed for ADONIS at ONERA
and Observatoire de Paris.
As a result, we want to reach the best coherence possible of our strategy with the national instrumental politics.
As previously reminded, this one is well structured at the national (or international) level so that our own
views are regularly confronted with the perspectives at this higher level and, for R&D notably, more and more
defined within the context of networks. Because of this and of the increasing complexity and cost of the TGE
general-User instruments, LAOG naturally acts within consortia for large projects.
The second guiding principle is to keep a good balance between instrumental research and involvement in large
instruments operations. A major, and rather specific, element in the LAOG strategy is in the strong willing to
keep this balance in the long-term since it provides very useful inputs, drawn from R&D results, to conceptual
studies of future large instruments. It is also a determinant piece of politics for the resources management. In
practice, LAOG may program one to two large projects in parallel to R&D programmes.
A third elements of politics is our intention to keep involved in spatial projects through R&D contracts where
our expertise in system conception and specific components development and characterization can be useful.
The question to get even more involved in the future is open, depending on the technological orientation of
space projects.
10.2.4 A logical sequence
To make it robust, the LAOG has always tried – and wants to do so in the future - to built its detailed strategy
on the wish to participate in the whole sequence of phases that go from instrumental research to general-use
instruments on TGE. This insures the best transfer of expertise from the technological field to the instrumental
design. The decision to get involved in given projects is therefore largely constrained by continuity needs : it
can be seen in the graph (Figure 10.1 that the projects IONIC, IONIC/CHARA, VITRUV belong to such a
sequence, as do IODA, PEGASE, DARWIN, or MMD, dedicated AO systems, or also NAOS, VLT-PF, EPICS.
With appropriate collaborations, the goal to participate in each phase of such sequences, i.e. of a given instrumental
objective, can be met provided that R&D be based on the present expertise at LAOG and that,
obviously, large instruments be selected by agencies for funding. It must be noted that this strategy implies
a commitment to already engaged operations. The VLT-PF for instance results from a 3-years long pre-study
and, providing decision is confirmed in late 2005, implies the LAOG commitment.
The resulting strategy can be summarized as follows, by emphasizing the priorities that were followed during
the current ”quadrennial period”:
• strengthening our efforts in R&D on IO for interferometry aiming both at developing 2 µm imagers
(VITRUV) and progressing towards 10 µm nulling interferometry (DARWIN)
• developing a new technology of deformable mirrors in view of the instrumental needs of ELT as well as
small telescopes
• taking benefit of the expertise acquired with NAOS to promote a concept of extreme AO-based imager
(VLT-PF)
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