The Kaiser-Squires inversion is used in observations of this phenomenon to reconstruct massdistributions. The OGLE and MOA projects use this phenomenon, and in particular detect thisphenomenon within Baade's window of the Zone of Avoidance. The galaxy cluster Abell 370 is knownfor the arcs caused by it. The "Old Faithful" QSO 0967+561 double (*) quasar was the first object foundto be imaged twice 
The Kaiser-Squires inversion is used in observations of this phenomenon to reconstruct massdistributions. The OGLE and MOA projects use this phenomenon, and in particular detect thisphenomenon within Baade's window of the Zone of Avoidance. The galaxy cluster Abell 370 is knownfor the arcs caused by it. The "Old Faithful" QSO 0967+561 double (*) quasar was the first object foundto be imaged twice due to this phenomenon. The micro- version of this phenomenon is used to detectextrasolar planets, and it is responsible for Einstein rings. For 10 points, name this phenomenon in whichlight is bent due to the curved spacetime around a massive object.
The Kaiser-Squires inversion is used in observations of this phenomenon to reconstruct massdistributions.
gravitational lensing