SIMBAD references

In preparation for optical/IR interferometric searches for substellar companions of nearby stars, we undertook to characterize the fields of all nearby stars visible from the Northern Hemisphere to determine suitable companions for interferometric phase referencing. Because the Keck Interferometer in particular will be able to phase-reference on companions within the isoplanatic patch (30") to about 17th magnitude at K, we took images at V, r, and i that were deep enough to determine if field stars were present to this magnitude around nearby stars using a spot-coated CCD. We report on 733 fields containing 10,629 measurements in up to three filters (Gunn i, r and Johnson V) of nearby stars down to about 13th magnitude at V.