I doubt that anything as important as watching out for asteroids that might be heading for Earth and be big enough to be a problem is done by professionals manually looking through telescopes. It is almost certainly done by means of the telescopes being controlled by computers that know what to look for. It may well be that professionals are consistently monitoring such searches if only to see what else may be of interest way out there.

There are several organisations in America doing this including NASA. Another one was set up by a former American astronaut.