Working with Dale Frail, Wolszczan carried out astronomical observations from the Arecibo Observatory in Puerto Rico that led them to the discovery of the pulsar PSR B1257+12 in 1990.
Lucrând cu Dale Frail, Wolszczan a realizat observări astronomice la Observatoul Arecibo din Puerto Rico, unde a descoperit pulsarul PSR B1257+12 în 1990.