Measurements of the reflectivity are performed periodically for each of the three mirrors of T90 telescope. Four graphs corresponding to the mirrors M1 (primary), M2 (secondary) M3 (tertiary) and total reflectivity are shown from April 2010 to October 2014. The measurements have been reali out at different wavelengths: blue (470nm), green (530nm), red (650nm) and infrared (880nm).
Substantial improvements are evident after the aluminization of mirrors in September 2010 as well as the periodic cleaning made to date.
