It is known that the energy distribution in the star spectrum is one of the most important characteristics of radiation. Traditionally Vega is taken for the fundamental spectrophotometric standard. In relation to Vega spectrum the network of the secondary standards, uniformly distributed over the sky, is created (see for example [1 ] ). Then, by the Vega and by these standards the data of measurements for other stars close by distributed to them by zenithal distance, are absolutized. The basic requirements to a standard are the radiation stability in time, because if the variation of the star standard is unknown or it is not taken into account during the observation data processing, then it leads to increasing the catalogues and actual measurements error. Besides, the standard star spectrum should be purely stellar. In other words, the star should not have any peculiarities in spectrum, it should not be fast rotator and it should be no dust and gas around it.