Astronomical red shift
The red shift observed in astronomy occurs because of the emission and absorption spectra for atoms.
These atoms are well known and calibrated from spectroscopic experiments throughout the world. Although distant objects may be slightly blurred, it is by no more than can be explained by thermal or mechanical motion of the source. It is for this reason and others that red shifts observed are due to some combination of the three established forms of Doppler-like red shifts.
In nearby objects, within the Milky Way galaxy, observed red shifts are related to the line of site velocities associated with the objects being observed. Such observations of red and blue shifts have enable astronomers to measure relative velocities of objects orbiting the stars in the Milky Way galaxy. Small shifts around individual stars allow astronomers to diagnose and measure the presence of and characteristics of planets around the stars.
Measurements of red shifts in fine detail are used in helioseismology to determine the precise movements of the photosphere of the sun.
Red shifts have laso been used to make measurements of the rotation rates of the planets.