An odd technological ritual/operation.
Despite it's mystical result, Star Light Conversion is done by mathematical principles, such as astronomy and engineering, it draws starlight and captures it, somehow creating a mystical energy that can be used for a variety of ways. While primarily used to power technology or to replicate a Lantern Ring, the energy can be used to restore the power of a mystical being. However due to the mystical nature associated with the process, few advance races attempt such a thing and few mystical races have the scientific know-how to perform such an operation.
The process is based of a Hellboy Comic that co-stared DC comics Starman. His cosmic rod was powered by this (similar) process.