Project description

The goal of the `OHANA project is to coherently link the adaptive optics equipped telescopes on top of Mauna Kea with single mode infrared fibers into a very long baseline optical interferometer. This idea was first proposed by the late Jean-Marie Mariotti (1996) [9], [10] and has become viable due to two recent technological breakthroughs:

• Large telescopes can now be equipped with adaptive optics, providing Strehl ratios at least 0.3 at 2 microns on faint sources (R<14$\sim$15).
• Coherent light transport and coupling with single mode fibers in K and L bands is routinely demonstrated with the IOTA/FLUOR interferometer, leading to scientific results with unprecedented quality of visibilities (0.3% stability)

There is no other site on earth which provides the combination of superb seeing, largest collecting areas with AO, near kilometric baselines and easy potential cooperation between partners. The long baselines and the large apertures extend the scientific capability of existing ground interferometers (VLTI, KI) and complement future space missions (TPF, Darwin/IRSI). While at the same time this project will allow to address the longer term and broader issues regarding the role of hectometric or kilometric arrays of large telescopes.

The resolution at 2 microns of an 800 meter baseline such as that defined by Subaru and CFHT or Gemini is 0.5 milliarcseconds. Conservative estimates of the limiting magnitudes for visibility determination (Perrin et al, 2000 [12]) lead to a value of K=12 in snapshot observing. The severe competition for observing time must be weighted against the scientific capabilities offered by these factors.