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Maker, Unknown, probably English. c. 1890. Movement  5h" x 12" dia. / 11"h x 13" over hexagonal glazed case. Clock work driven orrery with Earnshaw type, split bi-metallic chronometer detent escapement with jeweled potence pivot and driven with chain fusee. Eight day duration. An additional spring barrel drives the orrery with one year duration. It also serves to eliminate the backlash that would be present in a mechanism with so many wheels. Subsidiary dial for the Bisextile, four year (leap year) cycle. Outer ring with year calendar and zodiacal indicators. Orrery with two inner planets, Mercury and Venus with rings to indicate each planet's orbital inclination to the sun. Also a separate tellurian depicting the Earth and moon system, with moon phases, the moon's orbital inclination in relation to the ecliptic represented by a ring around the Earth and a track for the moon to physically rise and fall with respect to the Earth, an indicator to show where it rises and sets relative to the surface of the Earth, below a subsidiary dial for moon's age and phases. The Earth at correct inclination with dial ring above divided into two twelve hour sectors illustrated with Roman numerals rotating with the earth. An apparatus connecting the earth to the Sun to shows the Sun's zenith and declination around the Earth as well as lines showing the approximate areas of sunrise and sunset in the Northern hemisphere. The entire mechanism pirouettes upon its central spindle once per year with indicator hand for outer silvered ring to indicate the position of the sun in the ecliptic as well as the date, month and zodiac house. All subsidiary dials engraved and silvered on skeltonized frame with unique upper and lower plates (not mirrored) held by nine pillars. Total of 45 wheels within the mechanism.

Here we see a close up of the dial below the Earth/Moon system. It has the four phases of the moon as well as the 29 divisions and numbers. Notice the small roller attached to the tube holding the moon. This rides along an inclined ring above the main star ring, and allows visual representation of the moon's orbital inclination with respect to the Earth. The moon also rotates correctly with respect to the Earth. Furthermore one can see the angled gearing used to turn the earth on its axis and to give the correct 23.5 degree tilt with respect to the Sun.

Here we see a close up of the dial below the Earth/Moon system. It has the four phases of the moon as well as the 29 divisions and numbers. The engraver gave us a very cheerful disposition for the moon!

Now a close up of the time dial. The hands have a beautifully chisled detailed. The hole cutout is for the winding square attached to the chain fusee used to wind a separate spring barrel to drive the chronometer escapement for the clock. This has an eight day duration.

This is the leap year dial and is written in Latin. Commune means common. So we have the three common years with the Bissextile year, again Latin for the leap year. Note the scalloping of all of the dial edges in the movement as well as the chiseled dial hand. The dial has a cutout for the winding arbor of the spring which drives all of the orrery's complications as well has moving the entire mechanism yearly around its central axis. This spring has a four year duration.

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