To problem of fluid equilibrium figures in round ring

Equilibrium figures in the manner of the Maclourin spheroid, inhering inwardly flat broad gravitational ring is investigated. The general formula for the angular velocity of the Maclourin spheroid, presenting perturbance from the ring is received in tidal approximation. For example, the influence of ring on the planet Saturn turns out to be negligible small. Regarding the accuracy of modern observations it becomes possible to neglect the influence of ring planets of solar system on oblateness of the Sun. However, galaxy's rings can produce the effect, which is comparable with the effect of the stellar system rotation.