Examples from the Web for heliostat
In a short time we might earnestly wish for a centrifugal apparatus or a heliostat.More Letters of Charles Darwin Volume II|Charles Darwin
In the absence of a heliostat it is more convenient to obtain a point of light with the aid of a lens of short focus.
Images of the sun are thrown into the observatory by an ingenious instrument run by clockwork, and called a heliostat.
In the absence of a heliostat the latter was the more convenient.