(Super)NOVAS has readily implemented the IAU2006 (P03) precession model (Capitaine et al. 2003). The improved precession model is matched with the IAU2000-R06 nutation model, which is a slight adjustment to the original IAU2000A coefficients to match P03.

We should update the SuperNOVAS precession / nutation models to the latest standard.

• (Re)implement the IAU2000 nutation model with data from https://iers-conventions.obspm.fr/content/chapter5/additional_info/tab5.3a.txt / b.txt.
• Provide new IAU2000B equivalent truncated series from the adjusted IAU2000A R06 nutation model.
• Rescale the low-precision IAU2000 series according to the recipe of Coppola, Seago, & Vallado (2009) to match.