provided but it is not illustrated in the drawings a motor and a worm gear mounted between the bearing 413 shown in fig1 and the shaft 401 the sand shield 402 would extend over this motor and protect it from the environment in order to control the mirror surface in elevation there would be mounted a stepping motor on the surface 407 with a worm gear that would drive the mirror shown in fig3 and this motor would preferably be located near the top west edge of surface 407 and would be so positioned that when the mirror is stowed as in fig5 the motor and the worm gear driving the mirror would all be inside the box and protected from the environment fig6 shows another embodiment of a protective enclosure for a heliostat mirror the fiberglass epoxy platen 501 has a reflecting surface 500 turned toward the sun the platen is mounted on a horizontal shaft 502 which permits rotation to change the elevation angle of the mirror the shaft 502 is supported by a flat end piece 503 of a cylindrical enclosure 504 which has a closed surface bottom 505 and closed back 506 an open front side 507 and an open top 508 over the open top is a hinged lid 509 with a closed top 510 a closed cylindrical back 511 an open bottom 512 and closed.