The Constellations

The Brightness of Stars 

Measuring Distance in Space

The way we measure the distance to other stars and galaxies depends on how close to us, and how bright they are. The accuracy of some of these methods is the subject of controversy because the distances are so enormous, and there is a reasonable degree of innaccuracy in the measurements.

• Stars that are quite close to us can be measured using the parallax effect.
• Other stars can be measured by comparing their relative magnitude with their expected or absolute magnitude.
• Pulsating red giants or Ceiphid stars  give a clue to their distance, and finally
• we can attempt to measure the distance using the Doppler effect.