17 relations: Achromatic lens, Astronomical seeing, Astronomy, Filar micrometer, Friedrich Bessel, Great refractor, Greek language, John Dollond, Joseph von Fraunhofer, Micrometer, Objective (optics), Pierre Bouguer, Season, Stellar parallax, Sun, W. H. Freeman and Company, 61 Cygni.
An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration.
Astronomical seeing is the blurring and twinkling of astronomical objects like stars due to turbulent mixing in the Earth's atmosphere, causing variations of the optical refractive index.
Astronomy (from ἀστρονομία) is a natural science that studies celestial objects and phenomena.
A filar micrometer is a specialized eyepiece used in astronomical telescopes for astrometry measurements, in microscopes for specimen measurements, and in alignment and surveying telescopes for measuring angles and distances on nearby objects.
Friedrich Wilhelm Bessel (22 July 1784 – 17 March 1846) was a German astronomer, mathematician, physicist and geodesist.
Great refractor refers to a large telescope with a lens, usually the largest refractor at an observatory with an equatorial mount.
Greek (Modern Greek: ελληνικά, elliniká, "Greek", ελληνική γλώσσα, ellinikí glóssa, "Greek language") is an independent branch of the Indo-European family of languages, native to Greece and other parts of the Eastern Mediterranean and the Black Sea.
John Dollond FRS (10 June O.S. (21 June N.S.) 170630 November 1761) was an English optician, known for his successful optics business and his patenting and commercialization of achromatic doublets.
Joseph Ritter von Fraunhofer (6 March 1787 – 7 June 1826) was a Bavarian physicist and optical lens manufacturer.
A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for precise measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers.
In optical engineering, the objective is the optical element that gathers light from the object being observed and focuses the light rays to produce a real image.
Pierre Bouguer (16 February 1698, Croisic – 15 August 1758, Paris) was a French mathematician, geophysicist, geodesist, and astronomer.
A season is a division of the year marked by changes in weather, ecology, and amount of daylight.
Stellar parallax is the apparent shift of position of any nearby star (or other object) against the background of distant objects.
The Sun is the star at the center of the Solar System.
61 Cygni Not to be confused with 16 Cygni, a more distant system containing two G-type stars harboring the gas giant planet 16 Cygni Bb.