Gateways to the stars

Br. Guy Consolmagno: "Gateways to the stars." The Tablet, 29 July 2021, https://www.thetablet.co.uk/features/2/20387/gateways-to-the-stars

Once, asteroids were nothing but tiny dots of light in a telescope. Then, about 50 years ago, we began to pass that light through “BVR” filters – glasses tinted blue, “visual” (green) and red – to see if these asteroids come in different colours…