  We present a compact and bichromatic imaging system, located outside of the
vacuum chamber of a trapped ion apparatus, that collects the fluorescence of
230.6 nm and 369.5 nm photons simultaneously on a shared EMCCD camera. The
system contains two lens doublets, consisting of a sphere and an asphere. It
provides a numerical aperture of 0.45 and 0.40 at 230.6 nm and 369.5 nm,
respectively, and enables spatially resolved state detection with a large field
of view of 300 $\mu$m for long $^{115}$In$^+$/$^{172}$Yb$^+$ Coulomb crystals.
Instead of diffraction limited imaging for one wavelength, the focus in this
system is on simultaneous single-ion resolved imaging of both species over a
large field with special attention to the deep UV wavelength (230.6 nm) and the
low scattering rate of In$^+$ ions. The introduced concept is applicable to
other dual-species applications.
