  The Cherenkov Telescope Array (CTA) is the next-generation gamma-ray
observatory currently under construction. It will improve over the current
generation of imaging atmospheric Cherenkov telescopes (IACTs) by a factor of
five to ten in sensitivity and it will be able to observe the whole sky from a
combination of two sites: a northern site in La Palma, Spain, and a southern
one in Paranal, Chile. CTA will also be the first open gamma-ray observatory.
Accordingly, the data analysis pipeline is developed as open-source software.
The event reconstruction pipeline accepts raw data of the telescopes and
processes it to produce suitable input for the higher-level science tools. Its
primary tasks include reconstructing the physical properties of each recorded
shower and providing the corresponding instrument response functions. ctapipe
is a framework providing algorithms and tools to facilitate raw data
calibration, image extraction, image parameterization and event reconstruction.
Its main focus is currently the analysis of simulated data but it has also been
successfully applied for the analysis of data obtained with the first CTA
prototype telescopes, such as the Large-Sized Telescope 1 (LST-1). pyirf is a
library to calculate IACT instrument response functions, needed to obtain
physics results like spectra and light curves, from the reconstructed event
lists. Building on these two, protopipe is a prototype for the event
reconstruction pipeline for CTA. Recent developments in these software packages
will be presented.
