- 350 years after Roemer's 1676 announcement, the authors used telescopes with resolution similar to late 17th-century instruments to confirm his method for measuring the speed of light.
- Roemer's method yields values for c within about 10% of the modern value, even with a simple model of uniform circular motion.
- Increasing model complexity (e.g., including Jupiter's elliptical orbit) does not always improve accuracy due to other perturbations.
- Using modern ephemerides gives a precise result of c = (298200 ± 1900) km/s.