Three scientists at Kitt Peak National Observatory have calculated that Neptune's rotation period is 18.2 hours plus or minus 24 minutes. This, the most accurate estimate to date, takes planetologists one step closer to understanding the distant planet's structure and chemical composition. In addition, knowing the planet's rotation rate helps to understand better the forces that affect its atmosphere.Michael J.S. Belton, Lloyd Wallace, and Sethanne Howard base their calculations on 300 observations made in 1980 in the infrared part of the electromagnetic spectrum.