The International Dark Sky Discovery Center in Fountain Hills invites the public to celebrate a major milestone in the construction of the Discovery Center – the placement of the dome roof for the Craig and Ruth Gimbel Hyperspace Planetarium.

Planetariums utilize a large dome-shaped projection screen onto which scenes of stars, planets and other celestial objects can be made to appear realistically to simulate their motion. Besides astronomy, planetarium programming may include biodiversity, anatomy and aviation.

At 9 a.m. Monday, Dec. 23, a 50-ton capacity crane will be at the site to lift the 38-ton, steel-ribbed, plywood-wrapped, 36-foot-high planetarium dome onto the foundation pillars that will be its home. The dome was constructed apart from the building to allow better access for placing the ribbing and sheeting.

Brief remarks will be given by Arizona State Senator John Kavanagh, Fountain Hills Mayor Gerry Friedel, McCarthy Builders Project personnel and Discovery Center President Joe Bill.

The lifting process is complex, and preparations will begin early in the morning. Things are expected to go smoothly so that the actual placement will occur shortly after the brief remarks. Complications, however, though not affecting the timing of the remarks, could affect the timing of the placement.

The public will gather at the Centennial Circle.