Nicolas Clerc (CFHT)

Title : OHANA phase II : Optical path difference model for the CFHT-Gemini link

Abstract : The OHANA project (Optical Hawaiian Array for Nanoradian
Astronomy) aims at linking the largest telescopes at the summit of the
Mauna Kea, Hawaii, in order to build a huge interferometer allowing
the exploration of very high angular resolution images (from a
fraction to a few milliarcseconds), without neglecting the
sensitivity, which should reach a magnitude 12 in visible and near
infrared domains.  After presenting a short review of the goals and
expectations of the project, I will discuss the problem of baselength
measurements and propose some ideas for a general Optical Path
Difference model. Since the Mauna Kea telescopes were not supposed to
work together, how is it possible to link them into a coherent
instrument with a 0.001% accuracy ?