Astronomical imaging using aperture synthesis telescopes requires deconvolution of the point spread function as well as calibration of instrumental and atmospheric effects. In general, such effects are time and frequency dependent and vary across the field of view as well, resulting in direction-dependent (DD), time-varying gains. With the improved sensitivities of the various next generation radio telescopes, direction dependence of such effects needs to be account for in imaging and calibration algorithms.
In this talk, I will discuss the algorithmic and computing challenges in developing efficient algorithms to correct for DD effects and describe some advances made towards this goal.