Eta Orionis(978.5 light years to Earth) is a 2.25 magnitude multiple star located in the west of Orion's belt between Delta Orionis and Rigel that is assigned to the oldest and closest part of the association, OB1a which is  a group of massive stars that includes most of the bright stars of Orion.
3.42 (4.50 + 5.90 + 5.65 + 4.95) 
Eta Orionis drops in brightness every four days from a combined apparent magnitude of 3.31 to about magnitude 3.6. 
