The ESO/MPG WFI and the INT WFC wide field archives comprising 330,000 images
were mined to search for serendipitous encounters of known Near Earth Asteroids
(NEAs) and Potentially Hazardous Asteroids (PHAs). A total of 152 asteroids (44
PHAs and 108 other NEAs) were identified using the PRECOVERY software, their
astrometry being measured on 761 images and sent to the Minor Planet Centre.
Both recoveries and precoveries were reported, including prolonged orbital arcs
for 18 precovered objects and 10 recoveries. We analyze all new opposition data
by comparing the orbits fitted before and after including our contributions. We
conclude the paper presenting Mega-Precovery, a new online service focused on
data mining of many instrument archives simultaneously for one or a few given
asteroids. A total of 28 instrument archives have been made available for
mining using this tool, adding together about 2.5 million images forming the
Mega-Archive.Comment: Accepted for publication in Astronomische Nachrichten (Sep 2012