An **elliptical dome**, or an *oval dome*, is a dome whose bottom cross-section takes the form of an ellipse.^{[1]} 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.^{[2]}^{[3]}^{[4]}

## 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.^{[5]}

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".^{[6]}

## World examples

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

- A number of mosques in Cairo, Egypt,
^{[5]} - Part of St. Peter's Basilica, in Rome, Italy
^{[7]} - The Basilica of St. Lawrence, Asheville, in Ashville, 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,
^{[8]} - 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.

## See also

## References

**^**Arun, G (2006). "Behaviour of Masonry Vaults and Domes: Geometrical Considerations" (PDF).*Structural Analysis of Historical Constructions, New Delhi*.**^**"Visiting the largest elliptical dome in the world, in Vicoforte".*ItalyRiveirAlps*. Retrieved 2020-12-04.**^**Chiorino, Mario Alberto. "Modeling Strategies for the World's Largest Elliptical Dome at Vicoforte".*International Journal of Architectural Heritage*.**^**Aoki, Takayoshi. "Structural characteristics of the elliptical masonrydome of the sanctuary of Vicoforte".- ^
^{a}^{b}Elkhateeb, Ahmed Ali. "Domes in the Islamic Architecture of Cairo City: A Mathematical Approach" (PDF).*King Abdulaziz University Department of Architecture Faculty of Environmental Design*. **^**"Polyhedral structures that approximate an ellipsoid".**^**"The Engineering Behind Saint Peter's Basilica".**^**Kobielak, Sylwester (November 27, 2016). "Oval concrete domes".

## External links and references

### Creating elliptical domes

### Calculations

- Site for calculating figures related to elliptical domes
- Another site for calculations
- Dome calculator