I suspect that KStars does not precess position angles correctly. A position angle listed in a catalog with a given epoch (say, J2000.0) would likely be the angle with respect to the north direction that the object makes with the NCP (North Celestial Pole) at that epoch (i.e. the J2000 NCP). Since the current NCP is different from the catalog NCP, and since deep-sky objects remain relatively fixed as seen from space, the catalog position angle should remain fixed at the present day with respect to the *catalog NCP* and not the JNow NCP. However, reading the code in `Projector::findNorthPA` and `Projector::findPA`, it appears that we render deep-sky objects assuming that their catalog position angles are referred to the JNow NCP rather than the J2000.0 / catalog NCP. Two potential solutions to this are: 1. In the existing Projector::findNorthPA code, change the "small displacement" vector to point towards the J2000.0 NCP 2. Use the formula from Page 116 of Jean Meeus' book to compute the position angle of an object relative to the precessed location of the J2000.0 NCP in JNow, i.e.: * First, we precess the coordinates (undefined, 90°) from J2000.0 to JNow to get the current epoch coordinates of the J2000.0 NCP * Next, we use Meeus' relative position angle formula to compute the relative position angle of the J2000.0 NCP in JNow coordinates with the JNow coordinates of the object of interest * Then we add appropriately the PA of the object to this angle and render it This method is hard to get correctly with all the signs, so we can test it against the first method which is "hackish", but reliable. STEPS TO REPRODUCE 1. 2. 3. OBSERVED RESULT EXPECTED RESULT SOFTWARE/OS VERSIONS Windows: macOS: Linux/KDE Plasma: (available in About System) KDE Plasma Version: KDE Frameworks Version: Qt Version: ADDITIONAL INFORMATION