Monthly report for October 2001 by Christian A. Hummel: Hummel analyzed the first 5-station NPOI data and fixed some software bugs along the way. He computed fringe frequency power spectra to identify the different baselines, and successfully computed a closure phase from a baseline triangle on the second spectrometer. Hummel visited NRL to discuss the preliminary design of the observation planner for NPOI with Mozurkewich and Pauls. He also installed the OYSTER data reduction software on a SUN workstation at NRL. On a second visit to NRL, he gave a brief presentation at the MRO kick-off meeting on the OYSTER software, and in particular on the reduction of the 6-way data. Hummel refereed a paper for the Astronomocal Journal. Hummel traveled to Flagstaff and gave presentations at the NPOI quarterly meeting on the status of astrometry and 6-station reductions. He also presented a design for the new NPOI observation planner. While in Flagstaff, he helped with array work.