The Square Kilometre Array (SKA) calendar for 2020 celebrates the SKA family of pathfinder telescopes. April focuses on FAST (the Five-hundred-metre Aperture Spherical Telescope), the world’s largest and most sensitive single-dish radio telescope, which cover the frequency range from 70 MHz to 3 GHz. FAST, which opened in 2016 , has already detected over 100 pulsars, including some of the weakest radio pulsars ever detected.