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 jeweled chronometer
detent escapement 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, as well as the ecliptic. Below is 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.
Click on pictures for more detail.
View of orrery in glazed case. Click on photo for more details.