11. Baum used just a single globular cluster, but individual formations are often poor standard candles . 12. Thus, this relation does not employ standard candles . 13. This makes them very useful as standard candles . 14. It is used as a standard candle in the calibration procedure of X-ray instruments in space. 15. Usually, astronomers use standard candles : objects for which the intrinsic brightness, the absolute magnitude, is known. 16. So type Ia supernovae can be used as " standard candles " to determine their true distance. 17. Several methods rely on a "'standard candle "', which is an astronomical object that has a known luminosity. 18. Type Ia supernovae are the best-known standard candles across cosmological distances because of their extreme and consistent luminosity. 19. Standard candles used to measure the expansion history of the Universe also need to be corrected for dust extinction.20. So another type of " standard candle " _ one vastly brighter than the Cepheid variables _ is needed.
