I own a lunt 50 ha single etalon telescope with helical focuser and B600 cutting filter. I bought it two years ago in excellent condition from the previous owner in Athens. I use it mainly for imaging with a Zwo asi 178mm camera. The telescope up to now has worked exceptionally well. Three days ago, when I tried to image the sun, I noticed that I could not see the sun clearly on the laptop screen. When I increased the exposure (7ms) a very shiny asymmetrical disc appeared on the screen. The disc kept up increasing asymmetrically with the exposure time. When I decreased the exposure (0,5 ms) the disc disappeared almost completely except some grey dots in the center of the screen. I took snapshots but when the exposure was 7 ms, only a grey shadow appeared in the photo.In lower exposure times ,nothing appeared in the snapshot. I used another camera ( zwo asi 1600mm) and laptop but nothing changed. I tried all settings in both cameras and laptops but again nothing changed. The telescope has never fallen down or has ever been mistreated. I would appreciate it if you could help me find the cause of this failure and what can be done in order to fix it.