Experience with LHCb alignment software on first data

The LHCb (Large Hadron Collider beauty) experiment is designed to perform high precision measurements of B-meson decays. The construction and installation of the LHCb detector was finished early summer 2008, followed by intensive testing and commissioning of the system in order to be ready for the first data taking. Despite the forward geometry of the LHCb detector over 1 million cosmic events were collected and in addition beam dumps during the LHC synchronisation tests provided very useful data. These data allowed for first calibration and spatial alignments of several subdetectors. This note describes the alignment procedure and its underlying mathematics and will give results of the first spatial alignment of the tracking system done with the collected data.