Orion's belt stars. True-colour optical image of the stars Zeta Orionis (Alnitak, lower left), Epsilon Orionis (Alnilam, centre) and Delta Orionis (Mintaka, upper right) in Orion's Belt in the constellation Orion. Below Alnitak is the pink emission nebula IC 434, with the prominent Horsehead dark nebula (B33) projecting into it. This image was produced by digitally combining photographs taken by the UK Schmidt Telescope in blue and red light.