What is the difference between the light of Lucifer and what a right hand path Christian magician calls light ?
Hiya OP! Whereas one burns out your eyeballs and melts your brain, the other casts a kind of lantern over that which has remained hidden from you, like a torch.
Usually, Christian magicians (and Wiccans) use the word “light” as a synonym of “good”. However, if your idea of “good” is not the same as theirs, you would probably want to associate light with another thing that is better for you.
The Christian light is associated with “good” as said by @MagusOfGamaliel
Lucifer’s light is associated with ascension.
Don’t many Christians associate “good” with ascension, as in going to “Heaven,” becoming an “angel,” etc.? Additionally, don’t many (not all) Luciferians and magicians who work with Lucifer associate Lucifer with “good?” I’ve often heard Lucifer described as the “good” version of Satan precisely because of the association with light.