Projective equatorial sundial

Description.
This is the first Russian sundial of the design. The brass tape of 150 mm width and 350 mm in diameter is set in the equatorial plane. The sun casts the shadow on the screen. A polar line is etched on the screen. The shadow position relative to the polar line points the true solar time at the Moscow meridian. On the back (north) side of the screen, a detailed table of the equation of time is etched. The instrument is installed in the Moscow Planetarium in 2010.