The cosmic ray knee is generally understood as marking the limiting energy of galactic accelerators and/or the onset of increasing outflow of particles from the galaxy. Detailed measurements of the cosmic ray composition are needed to support this prediction. The model and detector systematics of these measurements can be reduced with shower-by-shower based measurements employing independent detection techniques. Here we discuss the potential of compact imaging air Cherenkov telescopes to contribute to the composition measurement in interplay with ground based particle detectors.