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Finish planisphere, begin Sun and Moon module, misc. setting dials  - November 2020

This month Buchanan continues to finish up the project. The planisphere is finished and the Sun and Moon module is begun and various setting and indicator dials are silvered.


The first photo shows the various wheels contained within the planisphere module. Next the largest wheel which beautifully shows the delicate spoke and hoop which are a hallmark of Buchanan's wheel work. The wheel is 5.25" (13.25 cm) and 516 teeth.


Various parts are being polished. The second photo shows a few polished parts.

This photo shows the parts of the planisphere case structure and base.

The rear plate of the planisphere is brought to a high polish and reflected is a view of the machine.


The first photo shows the upper wheel work section that contains the knurl knob to adjust the position of the Sun on the dial.


The planisphere main wheels mechanism is finished, front and rear views. Every time I see this I think it would make a beautiful great wheel skeleton clock. The curved 'wings' on each side are the locking levers that attach the planisphere module to the machine.


In this video the planisphere wheel work is finished. Doesn't it look like a beautiful great-wheel skeleton clock? The main wheel is 5.25" (13.2 cm) in diameter with 516 teeth.


The wheel works are now fitted to the rear of the planisphere frame which also has a pair of wheels that had to mesh perfectly with this assembly, see last month’s installment for this critical alignment procedure.


The engraving is filled with black enamel which is baked on top of the bluing oven, shown here are the planisphere and Janvier variable differential setting dials. This material gives a much more durable engraving filling than traditional dial wax. Next the finished setting ring for the enamel star dial plate.

Other setting and subsidiary dials are shown in this photo. The main dial work on the front of the clock is enamel, but the remaining dials located throughout the movement are engraved and French silvered. The dials shown are from the Sun and Moon as well as the orrery modules.


The first photo shows the setting dial around the rim of the star dial plate, next this is covered by the exterior rim in the second.

Here is a close up of the setting aperture, notice how the window has a nice bevel edge all the way around.


These two photos show parts returned from the plating firm and are coated in 24 karat gold, a total of 69 pieces.


In these photos Buchanan glues down the ecliptic ring for the Sun travel through the zodiac. Both the ring and the Sun have been plated. The eyes for the sun are tiny polished and blued screws complimenting his satisfied, wizened look.


Close up and three-quarter views of the planisphere mask.

Last month similar photos were made of the planisphere mask before plating, but the gold plating simply makes the construction outstanding, and the Latin engraving pop. The engine-turned pattern is perfect, the entire mask including the net is made from one brass blank.


Notice the complex stepped milling of the planisphere base and the mirrored rear face.


Another two views of the planisphere module.


It took a full month’s work to finish the planisphere mask, base and finish the wheel work. The planisphere is one of the more prominent features of the clock from the front and the extra work that was involved in its fabrication shows. It contains the most colorful dial work as well as 24 karat gold surface. The Sun is also plated and equipped with two blued steel eyes, May 2018, giving it a wizened and contented look. The inscription was part of an epic poem, Metamorphosis, written by Publius Ovidius Naso, commonly referred to as Ovid in AD 8 and is translated as: To man God gave an upwards gaze, bidding him to behold the sky, and raise his erect countenance towards the stars. When taken in the context of the poem it is when God separates Man from the animals by giving him the ability to stand erect and gaze toward the heavens, presumably to unite him with God in contrast with the downward earthly gaze of animals. Obviously Ovid was not familiar with primates! But given when he lived and that he was from Greece that’s understandable. The font chosen was Century Gothic seen in MS Word.

The video shows the finished planisphere module. If one looks carefully you can see the slight difference in color between the front mask and the cylindrical body of the module.


The first photo shows a literal faceted ruby “cap jewel”, this is one of a pair that will sit atop the two remontoire fly governor pivots and rotate atop the two towers of the machine. Next the strike train pull-repeat button complete with its gold chain. 

Buchanan now turns to the Sun and Moon module 


The finishing of the Sun and Moon module begins, various parts shown above. 


These are the sun rise and set shutter cams, calibrated to the latitude of Chicago at 41.880 N. These represent the whimsy that has been used where possible. The sunrise cam is represented by the Sun peeking out as it is rising complete with a set of steel ball-bearing eyes and sun rays for the spokes. We used a similar analogy for the spokes of the equation of time kidney cam created in November 2014 since that cam represents the difference in the position of the sun in the sky as compared to conventional mean solar time. In background is the sunset cam depicting the night sky complete with stars and a crescent Moon.


The Sun horizon cams flipped over from the photo above, next a part of one of the Janvier variable differentials, the slant wheel stirrup (fork) seen below to the left.


The first photo shows a frame containing the setting knob for one of the variable differentials, next other various parts. The sickle shaped gears operate the Sun horizon shutters.

Parts for the Sun and Moon module continue final finishing.


The first photo is the base wheel and frame for the Moon output. The gearing rotates the Moon on its axis and the entire system including the Moon revolves around the central bearing.


The Projection differential wheel work is finished.

The Great Anomaly wheel work is finished. Note the multiplicity of jeweled pivots and stark angles of several wheels. On the main slant wheel one can see near the 12 o'clock position on the inner rim a jeweled roller. This slides along the forked stirrup slot to produce the variable output.

The Projection differential complete with its French silvered setting dial. Note the extra turning work on the setting arbor below the knurled knob.

Both differentials used in the Moon's orbital anomaly corrections.


This video shows the pair of Janvier variable differentials used to correct the major two components of the Moon's orbital anomaly for display on a two dimensional dial. These are the Projection, which accounts for the Earth's tilt and elliptical orbit in relation to the Moon, and the Great Anomaly accounting for the largest of the Moon's anomalous orbit around the Earth.


This video shows the clock running in its temporary plastic case in November 2020. Notice that there are no weights which was the original design to drive the clock. It is now driven by motor springs and can be displayed at any height and on a solid table top. The case can also be more air-tight since weight lines are now eliminated. The current stand is left over from when a compliment of four weights totaling over 220 lbs. (100kg) would have hung from below, in addition to the weight of the stand at about 120 lbs. for total savings of 340 lbs. (155 kg). Holes will later be drilled in the front case panel to test winding and setting keys.

Parts count: 6782 

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