https://www.xloptix.com/blog/notes/Recent content in Notes on XLOPTIXHugoen-usSun, 18 Oct 2026 08:21:01 -0700https://www.xloptix.com/blog/2026/10/18/a-glass-galaxy/Sun, 18 Oct 2026 08:21:01 -0700https://www.xloptix.com/blog/2026/10/18/a-glass-galaxy/<p>Recently, a project led me down an interesting path. I applied linear Principal Component Analysis (PCA) to the index profiles of glasses in the SCHOTT glass catalog at 20°C. The Sellmeier dispersion equation for these glasses has six parameters, and accordingly, there were six principal components. However, the first three principal components captured most of the index-variation information. This, along with the fact that I cannot visualize more than three dimensions, led me to focus on the first three principal components for this visualization.</p>