Clayton Boyer Clock Designs


Celestial Mechanical Calendar and Orrery

The Celestial Mechanical Calendar shows the day of the week, day of the month and the month. In addition, she indicates the Zodiac Sun Sign and New Moon Ascension sign, has a MoonPhase Ball that indicates a nearly exact reflection of what the actual moon is doing in the night sky. She also has a Full Moon Ascension Window, and an Orrery showing the synodic rotations of the three closest planets, Mercury, Venus and Mars and indicates when they go into retrograde. The Celestial Mechanical Calendar also knows if the month has 28, 30 or 31 days and advances herself automatically. All of this with just the throw of a lever each day! It's exciting to see her go through her gyrations, spinning and sliding first to the right, and then back to the left, advancing the settings as she goes. The Celestial Mechanical Calendar measures 42" in width and 26" in height, and operates for seven days on a wind.

Looks daunting? Actually, it’s not. The plans come with an 11 page set of Explanations and Instructions that walk you through the process, page-by-page. All of the parts for this calendar are full-sized patterns so there is no measuring. The exception being the frame which is shown as a measured drawing, but included in the plans are Exact Centers Measuring Strips to get perfect alignment of all the parts. The only measuring that is required is 17 3/16” (43.7cm) over, and 1 3/8” (3.5mm) up on the frame’s base, and the rest of the measurements are contained in the Drilling Guides and Exact Centers Measuring Strips.

The Instructions break the building process down into four easy-to-follow sections. First we create and drill the frame, then we make the calendar’s wheels. The third part of the build is the motive clockworks that powers the calendar, and finally we add the levers and arms that link all the parts together.

The calendar is easy to get into adjustment, and operating correctly because of its wider tolerances. There are also instructions on which dates are best to use to test out the various functions of your calendar, and the best dates to use to set the Orrery.

Also explained is the movement of the Earth, its moon and the three closest planets and how that relates to what you will be seeing on the calendar throughout the year. The variance in the accuracy of the moon and planets on this calendar is usually within hours per year.

In my video below, I demonstrate some of the features of my Celestical Mechanical Calendar and Orrery:


John Hilgenberg's build of my CMCO is shown in his instructional video, Wood in Motion (appears at 3:34).

To see pictures of other builders' Celestial Mechanical Calendars, click on this link: CMCO Flickr Pool

And to see some more builders' CMCO's in action, visit our CMCO playlist on YouTube: CMCO YouTube Playlist

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