Technical data

Chapter 5 Starmap 22
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. It was compiled by
the Smithsonian Astrophysical Observatory. 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:
• Solar system • Named asteroids
• Comets • Numbered asteroids
• Common stars • Custom Catalogs
• Constellations • User planetoids
These databases allow you to select from a variety of objects. The Asteroid database is quite large and may cause a
delay while loading all of the names.
Pushing the Description button displays the Object Description dialog box that show all of the parameters of the
selected object. Pushing Center dismisses the dialog and redraws the Starmap with the requested object in the center
of the display.
Lock Az/El
The Lock Az/El commnad, will toggle the Az/El Lock. When the Az/El lock is checked, the lock is enabled. Enabling
the lock will keep the Starmap centered on the same Altitude and Azimuth, relative to a ground based observer as time
passes. When not locked, the Starmap will stay centered on the same R.A and DEC. coordinates.
Zenith Up
The Zenith Up command, will toggle the orientation of the displayed Starmap. When the Zenith Up is checked, the
the Starmap will be draw so that the local Zenith will be toward the top of the display. This is the orientation in which a
ground based observer sees the sky, or as it appear through an Alt./Az. Mounted telescope. When uncheck, the
Starmap will be drawn with the celestial pole towards the top of the display. This is orientation seen by observers
looking though equatorially mounted telescoped.
Magnitudes
The Magnitudes dialog box allows you to set the range of object magnitudes that will be displayed by the Starmap.
The default values are -5.0 for the brightest objects and 22.00 for the dimmest. All displayed objects are affected by
these settings, with the exception of the Sun and Moon which are always shown if the Planets are enabled.
Many of the deeps ky objects do not have assigned magnitudes, Autostar Suite defaults these objects to magnitude
22.00 when they are being displayed.
Because the display can quickly become cluttered as you zoom out to a wider field, Autostar Suite offers the option of
dynamically changing the Magnitude Limits for you. If you check the Auto Contrast switch, the program will