One of the most famous and most interesting stars in the sky. It is ranked as the 10th brightest star in the sky, but although being labelled as alpha it is usually slightly below beta or Rigel in brightness. It is a variable star normally varying between 0.3 to 0.8, its a semi regular variable star with a variable period of between 400- 1,000 days. However during during 2019 and 2020 it became much fainter than normal and caused astronomers many headaches.