A Hertzsprung–Russell diagram (HR diagram) is a visualization of star data which shows the relationship between magnitude and spectral characteristics. The diagram was created by Ejnar Hertzsprung and Henry Norris Russell independently in the early 20th century. You can read more about these diagrams here.
My visual uses the same underlying CSV as Mike Bostock’s visual, but simplifies the output and makes it smaller. It also detects user scrolls to turn individual star data points on and off to create a star-twinkle effect. The effect is most pronounced on smooth scrolls (such as a touchscreen device or trackpad).
In all, this is more of an exercise in art than data analysis. Enjoy!