V1 is a Special Class of Pulsating Star (IMAGE) NASA/Goddard Space Flight Center Caption NASA's Hubble Space Telescope has been trained on a single variable star that in 1923 altered the course of modern astronomy. V1 is a special class of pulsating star called a Cepheid variable that can be used to make reliable measurements of large cosmic distances. Credit NASA, ESA, and the Hubble Heritage Team (STScI/AURA) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.