STScI . Cluster Lensing: Peering into the Past, . Planning for the Future . ... HST . ... In HST Cycle 21, STScI will be launching the HST Frontier Fields campaign to obtain very deep ACS/WFC3 images of 4-6 high-magnification clusters and associated parallel blank fields. ... This seminar will provide an opportunity for the lensing experts to discuss how best to model the new deep HST cluster images, and for the general extragalactic community to learn how to interpret and use lensing models. ...