Celestial Flyways
A complete redesign and
rebuilding of
The park was designed by
Celestial Flyways
The park’s theme, Celestial Flyways,
was inspired by the migratory patterns of many bird species which pass through
the
The objective of the park’s
design is to give the park visitor a sense of
The centerpiece of the park is an interactive sculpture based on the anaphoric clock, a model of the sky with roots deep in antiquity. The anaphoric star disk in the park is very likely the largest and most accurate astronomical machine of this type ever made.
This discussion concentrates on the anaphoric star disk. The other aspects of the park, which are lovely and quite interesting, will be described in a forthcoming web site.
The anaphoric star disk consists of a 10 foot (3 m.) diameter disk containing the positions of 457 stars in 50 constellations. The stars are shown by holes in the disks filled by acrylic lenses and are lighted from below. Drawings of the mythological characters associated with the constellations are etched on the surface of the disk. Park visitors rotate the star disk to a date and time with a motor operated by buttons on the base. The mechanism is not a clock since it does not run by itself. If it were a clock, the disk would rotate once in a sidereal day.
Above the rotating star disk is a grid showing the local horizon and meridian, the celestial equator and the Tropic of Cancer. The Tropic of Capricorn is the outer diameter of the disk. The meridian is accurately oriented and the horizon corresponds to the latitude of the park at 39° 6˘ North.
The base of the sculpture is
decorated with ceramic representations of the
The outer circumference of the base contains a calendar and the outer edge of the disk has a time scale. Park visitors set the disk by aligning a time with a date. Once set, the stars are positioned for that instant.
The sun’s annual path, the ecliptic, is also engraved on the disk in the form of a calendar. The sun’s position for a day corresponds to a date on the ecliptic circle.
The star disk can be set for the current date and time to see the current positions of the sun and stars, set to find the time of a celestial event, such as sunrise or sunset or set to any other date and time of interest. It is a very informative display for such a simple machine.
The anaphoric star disk required the experience, talent and effort of a large number of people. The overall design was by Laura DeAngelis with Dominique Davison. The star positions, constellation asterisms, ecliptic, time scale and calendar were computer produced by James Morrison. The constellation figures were drawn by Laura DeAngelis and Peregrine Honig. Detailed design drawings were supplied by Davison Architecture + Urban Design. The disk, grid and supporting structure were fabricated by A. Zahner Co. The star lenses were made and installed by Louis Rose. The base ceramic decoration was made and installed by Laura DeAngelis and Louis Rose.
Evolution of a Constellation Figure
Anaphoric Star Disk
History and Design
The Celestial Flyways anaphoric star disk is based on the anaphoric clock. The name derives from the Greek anaphoros, which means rising and is specifically applied to the rising of stars. Such a display was particularly useful in the ancient world since much folk astronomy is related to seasons defined by the rising of certain stars just before the sun.
The history of the anaphoric
clock dates from before 50 BC. The
earliest surviving description of a machine of this type is from the writing of
the Roman author and architect, Marcus Vitruvius Pollio
(ca. 88 - ca. 26 BC), who in de architectura
[Book IX, Chap. 8, 8-15] describes a clock (a clepsydra or water clock) in
this form. It is almost certain the
Tower of the Winds in
The anaphoric clock was probably not the first astronomical machine, but it was surely one of the earliest and had enduring influence as a direct precursor of the astrolabe, and possibly the most influential one. The astrolabe was by far the most widely used astronomical instrument before the invention of the telescope.
The content of the anaphoric clock is defined from the stereographic projection which preserves circles and angles in the sky on the projection. All star coordinates, the tropics and ecliptic are precisely projected.
The
The time scale around the edge of the disk was aligned to the exact star positions for the park’s location. The park is located at 94° 35˘ West longitude, 4° 35˘ west of the center of the Central Time Zone. The disk is intended to show the location of the stars at the park’s location at a given civil time. Civil time is the same at all locations within the time zone so the time scale alignment is adjusted by 18 min. 20 sec. to account for the fact that it takes a star that amount of time to travel from the time zone center to the meridian of the park. The disk does not account for the equation of time.
The meridian is accurately surveyed to the precise North/South line through the installation.
Just as an aside, the stereographic projection of the horizon for the park’s latitude divides the meridian almost exactly in the Golden Ratio. The Golden Ratio is often used by artists and architects to provide an aesthetically pleasing balance. This somewhat surprising element adds to the artistic impact of the structure.
Star Disk Fabrication and
Installation
The anaphoric star disk was required to meet at least the following criteria:
- It must be rugged enough to withstand both frigid winters and boiling hot summers, rain, snow, ice and hail.
- It must be safe for park visitors.
- It must be virtually maintenance free.
- It must be as vandal proof as possible.
- It must be accurate.
- It must be pretty.
This challenge was taken on by A. Zahner Co. of Kansas City (http://www.azahner.com/). Some of the technical details of the fabrication follow. This brief description cannot begin to reflect the skill and creativity of the Zahner team, led by Bill Zahner.
The star disk is 122” in diameter, with 120” visible. One inch of the disk is covered by the calendar and grid to protect both the disk and park visitors.
The entire mechanism is designed to work without maintenance for many years. The surface of the disk is 18 gauge (0.05”) interference coated stainless steel, treated to provide a dark blue aluminum oxide surface that is very rugged. The stainless steel disk is mounted on a 0.190” aluminum base to provide rigidity at reasonable weight (the entire disk weighs 382 lb.). The disk structure is mounted on a rigid carousel to provide a firm base. The disk does not have a center support and the entire carousel/disk combination rotates on bearings around the outer edge.
The stainless steel was supplied in panels and roll cut into a variety of shapes to form the final disk. Each section of the disk surface is attached to the aluminum base with adhesive, with a gasket seal between the sections to provide for thermal expansion.
The characters associated with the constellations were etched using a photo-resist mask using a proprietary Zahner process. The star holes were drilled as the last step in the disk fabrication. Some of the star holes required drilling deep holes in the carousel beams.
The star locations and size, constellation asterisms, ecliptic and time scale were created from a PostScript program and converted to an Adobe Illustrator file that was accurately transferred to the disk with more Zahner magic. The constellation figures were hand drawn, scanned and included in another Adobe Illustrator file, from which the photo-resist mask was made.
The interior of the anaphoric star disk base provides drainage and electrical access for the lights and motor.
The ceramic tiles around the star disk base were all hand carved, colored and glazed by Laura DeAngelis. They required 3,000 pounds of ceramic material and hundreds of hours of firing and glazing. There is a string of LED’s around the base to light it at night. The lights are activated by a photoelectric cell so they come on in dim light. It’s gorgeous.
The following pictures show the evolution of the anaphoric star disk and, hopefully, communicate some of the skills and effort needed to bring it to life. The photos are from Chris Morrison, Robin Trafton, Laura DeAngelis and Eric Steele.
Site Preparation
The poured concrete base. Note the curb
for the carousel.
The Carousel. Note the bearings around the edge.
Curb with Carousel Installed
Installing the month caps
Aluminum Disk with some stainless steel
sections
The completed disk
The disk ready for installation
The disk on a truck, ready to
install.
Unloading the disk
Installing the disk. Note the special tooling designed by Zahner to slide the disk into the base.
Grid ready for installation
Installing the Grid
Ceramic Tiles around base. Note the perimeter lighting.
The completed anaphoric star disk in
place and working
Even a child can use it.
Dominique Davison, the architect, is in
the light blue coat.
Emily Morrison (age 5) demonstrating
the Star Disk
Briefing Mark Funkhouser,
the mayor of Kansas City (the tall gentleman with the goatee).
Gratuitous Picture of Laura DeAngelis and
James Morrison
Credits:
Lead Artist: Laura DeAngelis
Lead Architect: Dominique Davison, Davison Architecture +
Urban Design
Artist’s Team: Peregrine Honig,
James E. Morrison, A. Zahner Company
Contractor: Hoffman Cortes Contracting Company
Engineering: Antella
Consulting Engineers
SK
Design Group, Thornton Tomasetti
Landscape Architect:
Genus Landscape Architects
Funding:
Greater Kansas City Community
Foundation
Oppenstein Brothers
Foundations – Commerce Bank, Trustee
Richard J. Stern Foundation – Commerce
Bank, Trustee
Muriel McBrien
Kauffman Foundation
Bank of
William T. Kemper Foundation – Commerce
Bank Trustee
H & R Block Foundation
WallStreet Tower,
Inc.
M&I Bank
Francis Family Foundation
Lighten Fund
Stinson Morrison Hecker
LLP
Kansas City Power and Light
Missouri Bank and Trust
The Arts Council of Metropolitian
Kansas City – Arts KC Fund
J. E. Dunn Construction Company
Special Thanks:
Jackson County Parks and Recreation
Jackson County,
The Downtown Council
Downtown Community Improvement District
Taliaferro & Browne, Inc.
Kate Hackman
The Art Selection Panel
On a personal note, my involvement in the overall project was modest compared to many others. It was, however, a wonderful collaboration with outstanding people. I am deeply impressed by Kansas City. It is a vibrant city, rich with tradition and very fortunate to have a core of dedicated public servants and civic leaders who continue to enrich the urban experience. You should go there if you can. It’s a terrific place.
