ESA's lunar rovers complete simulated moon trials on Mount Etna

In Photos: See The Jaw-Dropping New Images Of Jupiter’s Clouds And Its Volcanic Moon Just Sent Back By NASA’s Juno Spacecraft

James Webb Telescope's fine guidance sensor provides us with first real test image James Webb

Sir John Herschel used a solar wedge attached to his telescope to observe the Sun in the mid 19th century. A solar wedge reflects 4.5% of sunlight towards the eyepiece and a second glass filter reduces the Sun's white light by a factor of 1,000 or more