Recently, we measured the spectrum of dysprosium on the 421 nm cooling transition with our homebuilt laser system. After amplifying the master laser seed in a homebuilt tapered amplifier stage, it is frequency doubled in a homebuilt bow tie cavity which delivers up to 460 mW of blue laser power. The five most abundant isotopes of dysprosium can clearly be identified in the spectrum shown below. The inset shows a picture of our main vacuum chamber where a beam of dysprosium atoms crosses the spectroscopy beam