A luminaire with a prismatic optic permits the nearly uniform distribution of light about the luminaire. The prismatic optic permits the use of directional light sources, such as light emitting diodes, while maintaining the uniform light distribution. Furthermore, a concave shape of the optic further enables uniform light distribution. When light emitting diodes are used, the luminaire further includes a heat sink to maintain a desirable operational temperature without negatively affecting the light distribution properties of the luminaire.