![Cylindrical Lampglow thumbnail](https://opn-web-afd-d3bfbkd5bcc5asbs.z02.azurefd.net/opn/media/images/afterimages/2022/22mar-01.jpg?t=638430689537174714)
Cylindrical Lampglow
The glow of a Th-Ar hollow-cathode lamp. Reflection of light can be seen at the glass walls of the confining cylinder. Image taken with a Canon EOS 450.
—Philipp Huke, Institut für Astrophysik, Georg-August-Universität Göttingen, Germany