  Understanding the sources, acceleration mechanisms, and propagation of cosmic
rays is an active area of research in astro-particle physics. Measuring the
spectrum and elemental composition of cosmic rays on earth can help solve this
question. IACTs, while mainly used for $\gamma$-ray astronomy and indirect
searches for dark matter, can make an important contribution here. In
particular, they are able to distinguish heavy nuclei in cosmic rays from
protons and lighter nuclei by exploiting the direct Cherenkov light emitted by
charged particles high in the atmosphere. In this paper, a method to
reconstruct relevant properties of primary cosmic ray particles from the
Cherenkov light emitted by the primary particles and the air showers induced by
them will be presented.
