Ground/space co-operation for interferometry.

PHAROS is a proposal to launch several low-power lasers on a satellite in a highly eccentric orbit and to use these lasers to provide a calibration source for both adaptive optics correction on large-aperture telescopes and for interferometric studies over baselines of up to kilometric dimensions. Diffraction-limited imaging of unresolved sources could be achieved using PHAROS for calibration of night-time observations on an 8 m telescope. This paper will explore the use of PHAROS for daytime observations and consider whether it is useful for solar studies.