  We attempt to detect optical GRB afterglows on images taken by the Canada
France Hawaii Telescope for the Very Wide survey, component of the Legacy
Survey. To do so, a Real Time Analysis System called "Optically Selected GRB
Afterglows" has been installed on a dedicated computer in Hawaii. This pipeline
automatically and quickly analyzes Megacam images and extracts from them a list
of variable objects which is displayed on a web page for validation by a member
of the collaboration. The Very Wide survey covers 1200 square degrees down to
i'=23.5. This paper briefly explain the RTAS process.
