We measure the brightness of a star by its magnitude. There are two types of magnitude:

Apparent magnitude is how bright an object is to us on Earth.

Absolute magnitude is how bright a star would appear in space from a certain distance.


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Magnitude animation Magnitude

The level of magnitude that we can see with different tools. From the left: Naked Eye, Binoculars, Small Telescope, Large professional Telescope, Space Telescope

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Cool Cosmos Luminosity

Astronomy Notes Magnitude System

Astronomy Notes The Magnitude System

Australia Telescope Outreach and Education Magnitude calculations