User manual MEADE AUTOSTAR SUITE

[. . . ] Meade Instruments Autostar Suite _ Desktop Observing For Windows_ Version 3. 12 7 January 2004 This document and the Autostar Suite software described herein, are copyrighted and are protected from reproduction, proliferation, and disclosure under the Copyright laws of the United States of America. Information in this document is subject to change without notice and does not represent a commitment on the part of Meade Instruments, Inc. The software and/or databases described in this document are furnished under a license agreement or nondisclosure agreement. The software and/or databases may be used or copied only in accordance with the terms of the agreement. [. . . ] Currently there are two different reference systems in use: the Julian reference (FK5) and the Besselian reference (FK4). The Julian system is based on a year that is exactly 365. 25 days in length. The Besselian system is based on the tropical year, which varies from year to year. In 1984, the International Astronomical Union adopted the Julian system and established that the new standard reference (Epoch) will be called J2000. 0. J2000. 0 begins on 2000 January 1, at 12:00 noon Dynamical Time (TD). Chapter 5 Starmap 21 To allow you to input coordinates from another epoch, such as B1950. 0, that epoch value must be entered into the Epoch field. To select the Besselian reference frame (FK4) select the FK4 (Fundamental Katalog 4) button, the Epoch field will then be set to B1950. 0. You may change the epoch year value, but the Besselian reference will be used instead of the Julian reference. Selecting the FK5 (Fundamental Katalog 5) button sets the Epoch to J2000. 0. Again, you can change the year value, but the Julian reference will remain. If you are entering star coordinates from a catalog other than one referenced to J2000. 0, you should enter the appropriate reference frame, FK4 or FK5 and set the catalog's epoch value. When the OK button is selected, all of the entered values will automatically be transformed from FK4 to FK5 if needed, then star's proper motion will be applied, then the coordinates will be precessed from the epoch year to J2000. 0 . If you redisplay the Custom Viewpoint dialog box, you will see the epoch value reset to J2000. 0 and the coordinates will now show their corrected J2000. 0 positions. Object Selection Displays the Object Selection dialog box. The Object Selection feature allows you to select an object from one of Autostar Suite's catalogs or from one of the object databases. There are four major catalogs: 1) Messier 2) NGC (New General Catalog) 3) IC (Index Catalog of Nebula) 4) SAO (Smithsonian Astrophysical Observatory) The Messier catalog was originated by Charles Messier (1730-1817) as objects "to be avoided while seeking comets". Many Messier objects are frequently called out by their NGC designations which sometimes leads to confusion. Autostar Suite translates Messier designations into NGC, with the exception of M24 and M45 (The Pleiades) which do not exist in either the NGC or IC catalogs. The New General Catalog of Nebulae and Clusters of Stars was first compiled in 1888 by J. L. E Dreyer. This catalog has been updated since its original publication and two subsequent Index Catalogs were produced. Objects from the NGC catalog have names such as NGC 1984, while the Index Catalog objects use names such as IC 939. The SAO star catalog contains position and other useful information on most of the known stars. The standard version of the catalog shipped with Autostar Suite contains all stars down to magnitude 8. 0, over 45, 000. In addition to the major catalogs, there are also a number of object databases: Chapter 5 Starmap · Solar system · Comets · Common stars · Constellations Named asteroids Numbered asteroids Custom Catalogs User planetoids 22 These databases allow you to select from a variety of objects. [. . . ] equinoxes - the two points on the Celestial Sphere where the Ecliptic crosses the Celestial Equator. focal length - the distance from the lens or mirror to the focal point. focus - the point in an optical system where all the image components are brought together. geocentric - coordinate system whose reference point is the center of the Earth. [. . . ]