Refinement of the crystal orientation matrix for the flat-cone diffractometer

A procedure for refining a crystal orientation matrix for the flat-cone diffractometer is discussed. The positions of the centers of gravity of refections obtained during routine data collection are transformed in such a way that they can be used as input to the least-squares procedures of Busing & Levy [Acta Cryst. (1967), 22, 457-464] or Shoemaker & Bassi [Acta Cryst. (1970), A26, 97-101]. The orientation matrix can be refined on the basis of the positions of all observed reflections, and not only of a selected sample, thus increasing its reliability. The procedure is particularly suited for protein crystallographic studies, as it makes it possible to compensate for crystal movements encountered during data collection.