Method for testing a spectrometer system, wherein the spectrometer system comprises a housing provided with a window, an illumination source, a spectrometer and at least one standard for internal recalibration, formed by a white reference, being arranged in said housing, wherein the standard is formed as an intensity standard and mechanically pivotable into a beam path extending from the spectrometer to the window, and wherein the method comprises the following steps: - identifying specific absorption bands of a fill gas, present in the housing, in a reference spectrum recorded by the spectrometer using the standard following a calibration of the spectrometer system, for which purpose the standard was illuminated by the illumination source and the light reflected by the standard was recorded by the spectrometer, with the standard arranged in the housing being pivoted into a beam path extending from the spectrometer to the window for the purpose of recording the reference spectrum, with a wavelength characterizing the respective identified specific absorption band being measured in each case such that measurement values are obtained for the wavelengths of the identified specific absorption bands, and with the fill gas comprising suspended water in the form of water vapor such that the specific absorption bands of water vapor are identified in the reference spectrum and in the test spectrum; - recording a test spectrum with the spectrometer using the standard, for which purpose the standard is illuminated by the illumination source and the light reflected by the standard is recorded by the spectrometer, with the standard arranged in the housing being pivoted into a beam path extending from the spectrometer to the window for the purpose of recording the test spectrum; - identifying the specific absorption bands of the fill gas in the test spectrum, with a wavelength characterizing the respective identified specific absorption band being measured in each case, such that measurement values are obtained for the wavelengths of the identified specific absorption bands; and - testing whether the measurement values of the wavelengths of the specific absorption bands of the fill gas identified in the test spectrum deviate by no more than a specified measure from the measurement values of the wavelengths of the specific absorption bands of the fill gas identified in the reference spectrum. - identifying specific absorption bands of a fill gas, present in the housing, in a reference spectrum recorded by the spectrometer using the standard following a calibration of the spectrometer system, for which purpose the standard was illuminated by the illumination source and the light reflected by the standard was recorded by the spectrometer, with the standard arranged in the housing being pivoted into a beam path extending from the spectrometer to the window for the purpose of recording the reference spectrum, with a wavelength characterizing the respective identified specific absorption band being measured in each case such that measurement values are obtained for the wavelengths of the identified specific absorption bands, and with the fill gas comprising suspended water in the form of water vapor such that the specific absorption bands of water vapor are identified in the reference spectrum and in the test spectrum; - recording a test spectrum with the spectrometer using the standard, for which purpose the standard is illuminated by the illumination source and the light reflected by the standard is recorded by the spectrometer, with the standard arranged in the housing being pivoted into a beam path extending from the spectrometer to the window for the purpose of recording the test spectrum; - identifying the specific absorption bands of the fill gas in the test spectrum, with a wavelength characterizing the respective identified specific absorption band being measured in each case, such that measurement values are obtained for the wavelengths of the identified specific absorption bands; and - testing whether the measurement values of the wavelengths of the specific absorption bands of the fill gas identified in the test spectrum deviate by no more than a specified measure from the measurement values of the wavelengths of the specific absorption bands of the fill gas identified in the reference spectrum.