[FeatureRush]

Wasn't it the other way around? A type of supernovas ("standard candles") were discovered before the expansion and used to discover the expansion? The formula for distance only uses absolute and apparent magnitudes to calculate distance?

[marcosdumay]

Yes, my comment above is wrong. It was the other way around.

[empath75]

Yeah they calibrated red shift from standard candles.

[funnuf]

They use luminosity for SNe Ia.