IfA Colloquium Series

Roberto Ragazzoni
Osservatorio Astronomico di Padova

Wednesday, May 23, 2001
IfA-Manoa Auditorium  3:30, Refreshments 3:15

Title

"Multi Conjugated Adaptive Optics with solely Natural Guide Stars:  a
dream, a possibility or a bench for Laser Guide Stars?"

Abstract

Multi Conjugated Adaptive Optics (MCAO) has been conceived more than a
decade ago in order to solve some of the major drawbacks of Adaptive
Optics, namely the limited Field of View of correction. In recent years,
whenever technological development convinced several groups that MCAO can
turns, in the coming years, from drawings to metal, a strong development on
this area started. The augmented Field of View and the problems, both
technologically and theoretical, with the usage of artificially generated
laser Guide Stars, leads to the suspicion that, allowing for a larger FoV
correction, chances to get enough natural stars for references could
augment enough to make such a choice an attractive one. I would like to
review my current view on these techniques and their potentiality in the
near future. These approaches, largely being based on the bottom line to
make a very efficient usage of the photons by natural stars, could also
translates into weaker demands on Laser Guide Stars power and complexity,
although the debate is still running in these days. The various
corresponding scenarios are briefly sketched and orders of magnitude for
sky coverages and attainable Sthrel are discussed.