Homebuilt Cathode Ray Tube

This is my first attempt at building a cathode ray tube. I used a Viot VPD3 15 micron pump to evacuate a chamber made using a modified wine bottle. The power supply is a 9kV 30mA NST, the same one that I used in my spark gap Tesla coil. The dark band around the center of the tube is caused by sputtering of the electrodes.