Determination of the dwarf novae parameters and their temporal changes

We present the development of a method for determining dwarf novae parameters and their temporal changes from the analysis of observations for several times. Using the modeling method of H I lines in the optical spectra of dwarf novae with high-temperature white dwarfs leads to large errors in the measured parameters. Therefore, the idea of using observations for several times was proposed, which will allow to determine the parameters of the system with greater accuracy. The dwarf novae FL Psc, which belongs to the WZ Sge type, was chosen as a test object. Its spectroscopic observations were carried out in 2021 and 2023 years by the 6-m BTA telescope. According to the light curve from the ZTF archive, in 2021 FL Psc was in a quiescent state, and in 2023 observations were made at the final stage FL Psc of relaxation to the pre-outburst level. The values of white dwarf temperature in both times of observations were obtained using the requirement of the invariability of the gravity value on its surface. However, similar temperature values in both times of observations differ from the literature predictions on the temperature increase of a white dwarf after a superoutburst.