• The most common reason for considering the spherical mirror is cost, a fraction of fisheye solutions. • The spherical mirror frees up the center of the dome, it is usually located toward the rim of the dome. The center of the dome is the best spot for the viewer and has safety implications not having cables and power routed to the middle of the dome. • The optics are separated from the projector. As such, the projector can be updated without needing to update the optics. Fisheye lens tend to be tied to the projector they were designed for. • There is more scope to vary the degree of dome coverage, one can choose less coverage and higher resolution, or more coverage (even 100%) but at lower overall resolution. • There is no proprietary hardware (or patents) making the technology accessible to a wide audience.