|
Hold the mirror up to a light and look from behind, if there are bits of coating missing you will see the light through them. The coating is thin so some light may show but any bad blemishes will really stand out. Looks like dust to me on your pic though. A bit of water won't hurt the cell and the colimation won't go out by much if you leave the mirror in the cell.
Last edited by doppler; 07-10-2017 at 12:48 AM.
|