 In previous segments, we have used parallax to verify and calibrate the HR diagram, also known as spectroscopic parallax, and standard candles like CFID and RR Lyra variables. These standard candles then enabled distance measurements far beyond what can be done with parallax. In this segment, we saw how to calculate the luminosity of type 1a supernova, and although globular star clusters come in a variety of sizes and magnitudes, it appears that the brightest clusters have a similar luminosity. Astronomers used the CFIDs and other known standard candles to verify and calibrate these two new standard candle rungs on our cosmic distance ladder, type 1a supernova, and the brightest globular clusters. Nebula and planetary nebula are about star death. In our next segment, we'll cover star birth nebula, like this one, the Orion nebula, as seen by the Zwicky transient facility.