The spectrometer methods and apparatus disclosed herein provide improved accuracy and can better accommodate variability among spectrometer systems and associated components. In many instances one or more of a calibration cover, an accessory, or a spectrometer are each associated with a unique identifier and corresponding calibration data. The calibration data associated with the unique identifiers can be stored in a database used to determine spectral information from measurements of objects obtained with individual spectrometer devices. The spectrum of the object can be determined in response to the unique identifiers and associated calibration data in order to provide improved accuracy and decreased cost.