A new ultrahigh vacuum (UHV) scanning tunneling microscope design has been developed and optimized forin situinvestigations of thin-film growth. The basic concept of the microscope is to retract the sample by means of the coarse positioning motor under an angle of 30° with respect to the piezotube scanner. This geometric arrangement allows normal film deposition and excludes any interaction between the evaporation beam and the tip. The instrument has the capability of regaining a particular microscopic location on the sample surface with an accuracy of less than 100 nm posterior to a sample displacement of more than 20 mm. Sequences of images of a spot during homoepitaxial growth of Cr on a Cr(100) single-crystal substrate have been obtained. ©1997 American Institute of Physics.