The Hertzsprung–Russell diagram (abbreviated as H–R diagram, HR diagram or HRD) is a scatter plot of stars showing the relationship between the stars' absolute magnitudes or luminosities and their stellar classifications or effective temperatures. The diagram was created independently in 1911 by Ejnar Hertzsprung and by Henry Norris Russell in 1913, and represented a major step towards an understanding of stellar evolution.
TL;DR Summary: How to understand the code determining the plot
Hi; this is the code I have been given for a H-R diagram of M35; I understand the inversion concept.. The plot is below. I am trying to understand the code that creates its position and size and how to alter it to a more...