Twistor spaces, conformal changes, and metric connections on the base manifold

Abstract The following problems related to almost complex structures on a twistor space are discussed: (1) when two almost complex structures defined by a morphism of the twistor space and two conformal metrics on the base manifold coincide; (2) when the Atiyah–Hitchin–Singer or Eells–Salamon almost complex structures on the twistor space defined by two metric connections on the base Riemannian manifold coincide.