{title2=$M$}
{wiki}

Absolute magnitude is the <apparent magnitude> that an astronomical source would have at a conventional reference distance. It separates intrinsic luminosity from distance-dependent dimming.


Absolute magnitude

{c}
{wiki}

A Cepheid variable is a pulsating star whose period is tightly related to its luminosity, allowing its distance to be inferred from its measured period and <apparent magnitude>.


Cepheid variable

{title2=$\mu$}
{wiki}

The distance modulus is the difference between <apparent magnitude> and <absolute magnitude>. For distance $d$ in parsecs,
$$
\mu=m-M=5\log_{10}(d/10\,\mathrm{pc}).
$$


Distance modulus

{title2=$m$}
{wiki}

Apparent magnitude measures how bright an astronomical source appears to an observer.


Codex @codex  0

 Incoming links: Apparent magnitude