Glossary+of+Terms

// Absolute: // the magnitude a star would have if it were at a distance of 32.6 light years from the observer // Apparent: // The measurement of the brightness of a star or other object in the sky as you see it from the earth ** Astronomical Unit ** (AU) the average distance between the Earth and the Sun (92,960,116 miles) ** Light year: ** The distance that light travels in one year, about 5.88 trillion miles ** Celestial sphere: ** The imaginary sphere out in space that surrounds the Earth and serves as a screen on which we see all the objects in the sky. ** Declination: ** the distance of an object north or south of the celestial equator measured in degrees. It is like latitude in maps of the Earth. ** Meridian: ** An imaginary line on the celestial sphere running north and south through the observer’s zenith and nadir. // Nadir: // the point on the earth directly below the observer // Zenith: // the point on the celestial sphere directly overhead ** Telescope: ** An instrument that gathers and brings light into focus; it allows astronomers to see or photograph objects too dim to be seen with the naked eye ** Internet telescope: ** A robotic telescope that can be operated from afar via the Internet ** Slew: ** the movement of the telescope on its axis to locate a target ** FITS ** (flexible image transport system) Digital file format used to store, transmit, and manipulate scientific images ** Star chart: ** An atlas of the night sky ** Constellation: ** a group of stars that form 88 sky patterns that are named for animals, heroes, and gods. ** Messier Catalog **: A catalog of celestial objects compiled by Charles Messier in the 18th century. Objects in the catalog are designated with a capital M and a number. For example: M64 ** NGC Catalog: ** Designates objects in the New General Catalog of star clusters and nebulae, originated by William Herschel in the 18th century and continued by his son John. Objects in the Catalog are designated with NGC and a number. For example: NGC 1252 ** // __ Deep Space Objects: __ // ** ** __Nebula__: ** A cloud of gas and dust among the stars; it can be observed in regions where new stars recently have been born and around dying or dead stars ** __ Star Cluster: __ ** // Open cluster: // irregular in shape, located in the spiral arms of our galaxy, contain 12 to hundreds of stars loosely held together – mostly contain young, hot stars. Over 1000 open clusters have been catalogued. // Globular cluster: // circular in shape, contains hundreds of thousands of tightly packed stars held together by a gravitational force, located in the galactic halo (space surrounding the galaxy). Two hundred globular clusters have been identified. ** __Galaxy:__ ** a vast island of stars, dust and gas forming one system // Elliptical: // have no spiral pattern and are uniform in appearance // Spiral: // spiral arms radiating from a central bulge // Irregular: // loose collections of stars with no well defined shape
 * __ Magnitude: __ **