Observations of secondary spectrophotometric standards in the wavelength range between 5840 and 10800 A

Twenty-three stars that are suitable for use as secondary spectrophotometric standards are compared with Alpha Lyrae in the wavelength range between 5840 A and 1.1 microns. The consistency of the present data with previously existing measurements is discussed, along with the reliability of the present data. It is found that there is good agreement with previous data in some cases, but moderate or substantial discrepancies are exhibited in others. It is suggested that extinction variation is the most probable cause of the discrepancies, and observational procedures that may improve the situation with regard to the discrepancies are proposed.