# Analyses of celestial pole offsets with VLBI, LLR, and optical observations

## TL;DR

This paper investigates alternative methods to VLBI for determining Earth's precession-nutation, focusing on lunar laser ranging and optical observations to leverage their long-term data for improved modeling.

## Contribution

It explores the potential of LLR and optical data to enhance Earth's precession-nutation models, updating previous results with recent high-quality data and extended time spans.

## Key findings

- LLR provides valuable long-period data for Earth's precession-nutation.
- Historical optical data can contribute to model improvements.
- Updated results with recent data enhance understanding of Earth's rotational dynamics.

## Abstract

This work aims to explore the possibilities of determining the long-period part of the precession-nutation of the Earth with techniques other than very long baseline interferometry (VLBI). Lunar laser ranging (LLR) is chosen for its relatively high accuracy and long period. Results of previous studies could be updated using the latest data with generally higher quality, which would also add ten years to the total time span. Historical optical data are also analyzed for their rather long time-coverage to determine whether it is possible to improve the current Earth precession-nutation model.