Variable stars, RR Lyrae, transients, supernovae, microlensing events.
Gravitational lensing is used to determine the masses of lensing galaxies and clusters and to study more distant galaxies that can be magnified by a factor of more than 20.
Typically, the target systems correspond to lensing of z > 0.5 star-forming galaxies by luminous red galaxies and brightest cluster galaxies.