Elliptical dome
# Elliptical dome

An elliptical dome, or an oval dome, is a dome whose bottom cross-section takes the form of an ellipse. Technically, an ellipsoidal dome has a circular cross-section, so is not quite the same.

While the cupola can take different geometries, when the ceiling's cross-section takes the form of an ellipse, and due to the reflecting properties of an ellipse, any two persons standing at a focus of the floor's ellipse can have one whisper, and the other hears; this is a whispering gallery.

The largest elliptical dome in the world is at the Sanctuary of Vicoforte in Vicoforte, Italy.

## In architecture

Elliptical domes have many applications in architecture; and are useful in covering rectangular spaces. The oblate, or horizontal elliptical dome is useful when there is a need to limit height of the space that would result from a spherical dome. As the mathematical description of an elliptical dome is more complex than that of spherical dome, design care is needed.

In a geodesic dome with a circular base, the triangular elements align so their edges form great circles. Although not geodesic, a new, elliptical design was patented in 1989; it uses hexagons and pentagons to form a dome with a cross section that is elliptical. Due to its mathematical derivation, this design is called "geotangent".

## World examples

Elliptical domes come up in the design of all of the following:

* A number of mosques in Cairo, Egypt,
* Part of St. Peter's Basilica, in Rome, Italy
* The Basilica of St. Lawrence, Asheville, in Asheville, North Carolina,
* The Church of Saint Roch, Žižkov, in Prague, Czech Republic,
* The Four Domes Pavilion, in Wroclaw, Poland,
* The Indiana Theatre, in Indiana, city of Indianapolis,
* The Joe and Rika Mansueto Library, at the University of Chicago,
* The Kanteerava Indoor Stadium, in Bangalore, India,
* The Mayflower Hotel, in Washington, DC,
* The Mosque–Cathedral of Córdoba, in Andalusia,
* The Palau Nacional, in Barcelona, Spain,
* The Pisa Cathedral, in Pisa, Italy,
* The Rose Hill Mansion, Bluffton, in Bluffton, South Carolina,
* The San Filippo Neri, in Turin, region of Piedmont, Italy,
* The Sant'Andrea in Via Flaminia, in Rome, Italy,
* The Santa Caterina, Casale Monferrato, in Casale Monferrato, Province of Alessandria, region of Piedmont, Italy,
* The Seville Cathedral, Spain,
* The Skyspace Lech, Tannegg/Oberlech in Vorarlberg, the westernmost federal state of Austria,
* The State Savings Bank Building, in City of Sydney, Australia,
* The Temple Sinai, in Oakland, California,
* The Sanctuary of Vicoforte, in Italy.
