It's really not clear what you're trying to ask here, since as stated the question is nonsensical: "star light" doesn't measure anything. Assuming that what you were trying to find out is how starlight is measured... the most accurate way is with a photometer.
Parallax
Magnitude
In Light Years with mathematics and some logical estimation.
Every star is a different distance. The distances are SO GREAT that we don't even measure them in miles - we measure them in light years, the distance light travels in a period of 365 days (almost six trillion miles)!! It's CRAZY !! The nearest star that we know of other than the Sun is about 4 light-years away.
Scientists measure light from star in light years because almost every other units would be so small compared to the distance involved between stars. in fact the nearest star (other then the sun) is 24689699219682.054 miles or 39734219301000 km.
A Light Year is a measure of distance. If a star is 61 light years away, then it would take light (or radio waves, which travel at the speed of light) 61 years to get there.
Light years, parsecs, and kiloparsecs. Light years and parsecs are used to measure distances between neighbouring star system's, kiloparsecs are used to measure distances within a galaxy.
That is called the absolute magnitude. It is a measure of the star's real brightness. Apart from the distance (10 parsec), another (implicit) assumption is that there is nothing in between that reduces the star's light.
To find the speed of a star using Doppler shift, you can measure the change in the wavelength of light emitted by the star. If the light is redshifted, the star is moving away from us; if it is blueshifted, the star is moving towards us. By analyzing the amount of shift, you can determine the star's speed relative to the observer.
Light Year is unit for all astronomic distances
Because, if we continued to measure the distances between star in miles, the numbers would be huge. One light-year is approximately equal to 5,865,696,000,000 miles !
The doppler effect is the change in frequency of a wave for an observer moving relative to the source of the wave. You can measure the location and velocity of a locomotive moving towards or away from your. You can measure a star's location and velocity vector regarding the shift and color emanating from the star light. This is calculated via doppler light equations.