Useful english dictionary. 2012.
diagonal eyepiece — noun : zenith eyepiece … Useful english dictionary
telescope — /tel euh skohp /, n., adj., v., telescoped, telescoping. n. 1. an optical instrument for making distant objects appear larger and therefore nearer. One of the two principal forms (refracting telescope) consists essentially of an objective lens… … Universalium
Meridian circle — Groombridge transit circle of 1806 The meridian circle, transit circle, or transit telescope is an instrument for observing the time of stars passing the meridian, at the same time measuring its angular distance from the zenith. The idea of… … Wikipedia
History of the telescope — The earliest known working telescopes appeared in 1608 and are credited to Hans Lippershey and Zacharias Janssen, spectacle makers in Middelburg, and Jacob Metius of Alkmaar. The design of these early refracting telescopes consisted of a convex… … Wikipedia
Optics — For the book by Sir Isaac Newton, see Opticks. Optical redirects here. For the musical artist, see Optical (artist). Optics includes study of dispersion of light. Optics is the branch of … Wikipedia
History of the single-lens reflex camera — The history of the single lens reflex camera predates the invention of photography in 1826/27 by one and a half centuries with the use of a reflex mirror in a camera obscura first described in 1676. Such SLR devices were popular as drawing aids… … Wikipedia
Star diagonal — A star diagonal is an angled mirror or prism used in telescopes that allows viewing of objects that are at a 90° angle from the direction the telescope is pointing. It allows convenient and comfortable viewing when the telescope is pointed at, or … Wikipedia
Aberration of light — Light from location 1 will appear to be coming from location 2 for a moving telescope due to the finite speed of light, a phenomenon known as the aberration of light. The aberration of light (also referred to as astronomical aberration or stellar … Wikipedia
Amateur astronomy — Amateur astronomy, a subset of astronomy, is a hobby whose participants enjoy studying and observing celestial objects. Overview The typical amateur astronomer is one who does not depend on the field of astronomy as a primary source of income or… … Wikipedia
Student microscope — A Student microscope is a low power, durable optical microscope typically sold in bulk for use in school science classes. Although university science students use microscopes, the term typically refers to the type of instrument used in primary… … Wikipedia
