**Abstract**

In general relativity, the stretching of the wavelengths of photons in the expanding universe occurs along the path and does not depend on the velocity of the source. Therefore, the photons from the sources at rest relative to us did not have, and from the sources comoving the expansion there was an initial Doppler redshift, and then on the way both photon fluxes acquired a stretching redshift. As the result, the redshift of the comoving the expansion sources should be at least doubled. But observations show a single redshift already in the linear part, and therefore in cosmological models only with redshifts (Friedmann's and others) there was the double redshift problem with one hundred percent discrepancy between theory and observations. The observational fact of single redshifts means that the photons should have an initial violetshift, which was compensated for along the way by one of two types of redshift. In the model of slowing time cosmology (STC) proposed in 2020, the rate of proper times was higher in earlier epochs, which led to the violetshift, compensated along the way by the stretching redshift. As a result, in STC the observed shift is reduced to the initial Doppler redshift, to which the gravitational redshift is added for distant objects. The relativistic aberration then leads to dimming of the apparent luminosities. The basic relations of STC are presented, including the “distance modulus – redshift”, which are consistent with observations at new values of cosmological parameters. Evolution in early epochs and its influence on the properties of CMB are also discussed. In STC the light velocity was higher in the past and for this reason it has no previously known cosmological problems.