Deneb

Its story

Deneb marks the tail of Cygnus the Swan and is one of the most distant beacons the unaided human eye can perceive: a blue-white supergiant of type A whose light has been travelling for 1,412 years to reach us. The photons arriving tonight left its surface when the Eastern Roman Empire still flourished and Charlemagne had not yet been born. Its name, «Al-Dhanab» in medieval Arabic, means precisely «the tail», and it forms one corner of the Summer Triangle alongside Vega and Altair.