ZERODUR, the glass ceramic, with CTE values near zero, has excellent performance up to 8.2 m primary mirrors as well as for lightweight (LW) mirrors for Secondaries and Tertiaries. The high homogeneity of major properties of ZERODUR is an important prerequisite for the LW production and application. The production of CNC grinding and subsequent lightening via acid etching for additional weight reduction will be discussed. Results of Secondary and Tertiary LW mirrors for advanced technology telescopes like 8 m, 6.5 m and 3.5 m telescopes will be addressed. This paper presents also some examples of space based satellites with LW Zerodur mirrors in use since several years.