H4E1L1I1O1S1T1A1T1S1
13 points
HELIOSTATS is validvalid
HELIOSTAT, [n]
HELIOSTAT, an instrument using a mirror to reflect sunlight in a fixed direction, used for studying the sun or signalling messages [n]
HELIOSTAT, [n]
HELIOSTAT, an instrument using a mirror to reflect sunlight in a fixed direction, used for studying the sun or signalling messages [n]