Cross Correlation Studies of Stellar Variability using Two Telescopes

The study of short time scale phenomena of astronomical interest is often handicapped by the presence of wide band noise. In particular, in the study of the optical variability of stars, such noise arises from atmospheric scintillation, extinction variations, sky radiance variations and photon statistics. For example if in order to resolve rapid stellar variability we reduce the length (T) of the time intervals over which a photometric record is integrated and sampled, we find that the fractional noise fluctuationsincrease, eventually obscuring any intrinsic variability.