By doing a simple magnitude estimate on a Type Ia Supernova, the distance of the galaxy it lies in can be estimated.
![](https://www.star-gazing.co.uk/WebPage/wp-content/uploads/2019/06/2011fe-M101.jpg)
Use my guide to estimating the distance of a galaxy using supernova maximum magnitudes.
http://www.star-gazing.co.uk/Downloads/SupernovaDistance.pdf