Ångström anders johan (2 Ergebnisse)

Disbound. Uncut. Very fine. Upsal, C. A. Leffler, 1862. 4to. [ii] + 10 pp. + large folding diagram. (Actes de la Société Royale des Sciences d'Upsal, Sér. III., t. IV.) - - - Halley is the only known short-period comet that is regularly visible to the naked eye from Earth, and the only naked-eye comet that might appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next appear in mid-2061. - - - "During the late nineteenth century, some astronomers had experimented with nontraditional ways of computing cometary orbits. The Swedish astronomer Anders Jonas Ångström (1814-1874) had adopted a statistical approach. Making no effort to address the physics of the orbit, he confined his attention to the dates of the comet's returns. From his analysis, he discovered that the average time between perihelions was 76.93 years and found that this period varied in a cyclical manner. With this information, he constructed a simple equation to predict the date of the perihelion. Applying this equation to all of the known sightings of the comet, he computed the date of every return. In most cases, the equation missed the actual date by only a few months.".…

Disbound, uncut & unopened. Outer margin of title darkened. Very fine. Uppsala,1875. 4to. 28,7 x 22,5 cm. [iv] + 34 pp. + 2 large folding plates. (Series: Nova Acta Reg. Soc. Sc. Upsal, Ser III, Vol. IX.).