The photographs on this page show a Dream ~29"
(4" thick) engineered lightweight mirror blank with an 8"
ID inner rim. The blank can be cast with a face at the center
or cast with a perforation. It was engineered specifically for
central support of lateral forces. Axial are loaded in a fairly
conventional 18-point arrangement, at the back surface of the
mirror. The smaller optic in the image above is a perforated
The Thermal Time Constant (TTC) of Dream's optic is
roughly 39 times faster than a thin (1-7/8" thick) monolithic
optic. When this cellular is compared to a 6:1 thickness ratio
(full thickness) monolithic mirror, the TTC of Dream's optic
is 251 times faster. The thermal load of the rest of the telescope
benefits from a substantially lighter M1 as well.