The CO N Deuterium Observations Receiver, CONDOR, is one of the very few existing THz heterodyne receivers in the world. It covers a frequency range between 1.25 and 1.53 THz (240μm 196μm). CONDOR was built with a focus on observing star forming regions, using high-J CO lines H2D + and N In November 2005 we tested CONDOR on the APEX telescope, and successfully observed CO 13-12 in several regions in Orion. In FIR4 we find a surprisingly narrow CO 13-12 line width (5.4 km/s), from which we conclude that the hot gas is probably radiatively heated rather than shock excited. The observations of NGC2024 reviled additional hot gas. In order to model the CO lines between J= 3-2 and J=13-12 consistently a model with molecular gas in 4 different layers is required. High spectral resolution observations in the THz regime allow us not only to probe gas otherwise difficult to observe, but also to obtain information about the structure and kinematics of the source.