William Harkness, a mathematics professor, inventor, hydrographer, medical doctor, astronomer, and meteorologist, was born in Scotland in 1837. Though showing interest in meteorology at a young age, Harkness turned to the medical field and received his degree from New York Homeopathic Medical College in 1862. He served as a volunteer surgeon with the Union forces in the Civil War and during the same year was appointed an aide on the staff of the U.S. Naval Observatory.

Following the Civil War, Harkness was directed towards a growing issue: discrepancies of magnetic compasses under the influence of ironclad ships. Harkness experimented by mounting four compasses of varying design to an ironclad ship, traveling to various ports around the world, and directing the ship to various cardinal directions while recording magnetic declination, inclination, and horizontal force — simultaneously comparing readings with true bearing. Through thousands of observations, Harkness produced the most elaborate study on behavior of compasses within armored ships ever recorded at the time.

During his years at the U.S. Naval Observatory, Harkness developed a series of technological improvements in spectroscope and photographic equipment, which attributed to incredible detail in his observations of total solar eclipses in 1869 and 1870. Following his observations, Harkness was appointed one of the original members of the Transit of Venus Commission, important for determining the scale of the solar system.

Transit of Venus, the passage of the planet across the sun’s discs, occurs in pairs separated by eight years and more than a century in between pairs. The astronomer Edmond Halley presented evidence in 1716 that this phenomenon could provide data on the sun’s parallax, its precise distance from earth, as well as other dimensions of the solar system. With his invention of the spherometer caliper, the most accurate instrument ever devised for determining figures of pivots of astronomical instruments, Harkness provided extremely accurate results.

During his work in astronomy, Harkness is best remembered for his research on solar parallax and its related constants. He conducted a complete inquiry into all previous observations of solar parallaxes and assigned each a precise value for degree of accuracy, of which the American Nautical Almanac differs by only a small fraction of arc. Amongst his achievements at the observatory, none should forget his theory of focal curve defining the color corrections of achromatic telescopes, which is universally accepted and currently in practice.

Following his retirement, the U.S. Navy bestowed upon Harkness the honorary rank of Rear Admiral in recognition of his work and 37 loyal years of service, and two Navy vessels have since been named in his honor.

The U.S. Naval Meteorology and Oceanography Command directs and oversees more than 2,500 globally-distributed military and civilian personnel who collect, process and exploit environmental information to assist Fleet and Joint Commanders in all warfare areas to make better decisions, based on assured environmental information, faster than the adversary.