, but this code // executes before the first paint, when

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is not yet present. The // classes are added to so styling immediately reflects the current // toolbar state. The classes are removed after the toolbar completes // initialization. const classesToAdd = ['toolbar-loading', 'toolbar-anti-flicker']; if (toolbarState) { const { orientation, hasActiveTab, isFixed, activeTray, activeTabId, isOriented, userButtonMinWidth } = toolbarState; classesToAdd.push( orientation ? `toolbar-` + orientation + `` : 'toolbar-horizontal', ); if (hasActiveTab !== false) { classesToAdd.push('toolbar-tray-open'); } if (isFixed) { classesToAdd.push('toolbar-fixed'); } if (isOriented) { classesToAdd.push('toolbar-oriented'); } if (activeTray) { // These styles are added so the active tab/tray styles are present // immediately instead of "flickering" on as the toolbar initializes. In // instances where a tray is lazy loaded, these styles facilitate the // lazy loaded tray appearing gracefully and without reflow. const styleContent = ` .toolbar-loading #` + activeTabId + ` { background-image: linear-gradient(rgba(255, 255, 255, 0.25) 20%, transparent 200%); } .toolbar-loading #` + activeTabId + `-tray { display: block; box-shadow: -1px 0 5px 2px rgb(0 0 0 / 33%); border-right: 1px solid #aaa; background-color: #f5f5f5; z-index: 0; } .toolbar-loading.toolbar-vertical.toolbar-tray-open #` + activeTabId + `-tray { width: 15rem; height: 100vh; } .toolbar-loading.toolbar-horizontal :not(#` + activeTray + `) > .toolbar-lining {opacity: 0}`; const style = document.createElement('style'); style.textContent = styleContent; style.setAttribute('data-toolbar-anti-flicker-loading', true); document.querySelector('head').appendChild(style); if (userButtonMinWidth) { const userButtonStyle = document.createElement('style'); userButtonStyle.textContent = `#toolbar-item-user {min-width: ` + userButtonMinWidth +`px;}` document.querySelector('head').appendChild(userButtonStyle); } } } document.querySelector('html').classList.add(...classesToAdd); })(); Mechanism and Restoration | »Æ´óÏɸßÊÖÂÛ̳

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Mechanism and Restoration

  • Clarence Menninga

The speed of the motions of the components of the planetarium is controlled by a balance-wheel clock, and the entire mechanism is driven by the mainspring of that clock. The mechanism below the platform consists of a system of 95 gears, which together with assorted eccentrics and levers move the visible part of the planetarium.

As much as possible, the original structure and components have been kept in place. Some badly worn parts of the clock were replaced. The wood platform on which the mechanism is mounted had shrunk over the decades, requiring hand-filing of some gears to reduce binding, and two broken gears were replaced.

While the mechanism is driven by the mainspring of the clock, the periodic rewinding of the clock is done by electric motor, triggered by microswitches which sense the wound/unwound condition of the mainspring.

The planetarium was restored to operating condition by Clarence Menninga (photo above), Professor of Geology, Emeritus, aided by John DeVries, »Æ´óÏɸßÊÖÂÛ̳ machinist.

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