Monthly report for July 2001 by Christian A. Hummel: Hummel used the new code developed in the previous month to do a dispersion correction of a long scan both as a whole scan and one divided into smaller units. This indicated a problem with the enforcement of the closure relations, and a modified correction algorithm was developed which is easier to understand and also works better. Hummel developed another test of the metrology data based on how well the pivot motions can be modeled using a three dimensional offset of the catseye center from the pivot. Hummel made some updates to the CONSTRICTOR code to prepare it for the NPOI 6-way data.