The pointing of Cherenkov telescopes is subject to imperfections which are, for example, related to
the bending of the telescopes mechanical structure. These imperfections must be measured, modeled, and finally corrected to
achieve an optimal telescope pointing precision. The measurement of pointing deviations is often
performed while the telescope points to different stars and a CCD camera
monitors the offsets of the star images to the center of the focal plane. Outliers in these
measurements can propagate into the pointing model and lead to imprecise model predictions.
CTbend is a simple and standalone open-source framework that uses a Bayesian
analysis with an outlier resilient likelihood function to model the pointing of Cherenkov
telescopes with parametric standard models like TPoint. The framework is described in the following.