  GH$\alpha$FaS a new Fabry-Perot system, is now available at the William
Herschel Telescope. It was mounted, for the first time, at the Nasmyth focus of
the 4.2 meter WHT on La Palma in July 2007. Using modern technology, with a
spectral resolution of the order R$\sim$15000, and with a seeing limited
spatial resolution, GH$\alpha$FaS will provide a new look at the H$\alpha$
-emitting gas over a 4.8 arcminutes circular field in the nearby universe. Many
science programs can be done on a 4.2 metre class telescope in world class
seeing conditions with a scanning Fabry-Perot. Not only galaxies but HII
regions, planetary nebulae, supernova remnants and the diffuse interstellar
medium are subjects for which unique data can be aquired rapidly. Astronomers
from the Laboratoire d'Astrophysique Exp\'erimentale (LAE) in Montr\'eal, the
Laboratoire d'Astrophysique de Marseille (LAM-OAMP), and the Instituto de
Astrof\'isica de Canarias (IAC), have inaugurated GH$\alpha$FaS by studying in
detail the dynamics of some nearby spiral galaxies. A robust set of
state-of-the-arts tools for reducing and analyzing the data cubes obtained with
GH$\alpha$FaS has also been developed.
