User manual CELESTRON NEXSTAR 80GTL Instruction Manual

[. . . ] Your NexStar telescope is designed to give you years of fun and rewarding observations. However, there are a few things to consider before using your telescope that will ensure your safety and protect your equipment. Warning · · · · Never look directly at the sun with the naked eye or with a telescope (unless using your Celestron solar filter). Never use your telescope to project an image of the sun onto any surface. Internal heat build-up can damage the telescope and any accessories attached to it. [. . . ] The display will ask you to enter a number between 1-25 to identify the object. Save Land Object: The NexStar can also be used as a spotting scope on terrestrial objects. Fixed land objects can be stored by saving their altitude and azimuth relative to the location of the telescope at the time of observing. Since these 18 objects are relative to the location of the telescope, they are only valid for that exact location. To save land objects, once again center the desired object in the eyepiece. The display will ask you to enter a number between 1-25 to identify the object. - Dec: You can also store a specific set of coordinates for an object just by entering the R. A. GoTo Object: To go to any of the user defined objects stored in the database, scroll down to either GoTo Sky Obj or Goto Land Obj and enter the number of the object you wish to select and press ENTER. NexStar will automatically retrieve and display the coordinates before slewing to the object. To replace the contents of any of the user defined objects, simply save a new object using one of the existing identification numbers; NexStar will replace the previous user defined object with the current one. Get RA/DEC - Displays the right ascension and declination for the current position of the telescope. Get Alt-Az - Displays the relative altitude and azimuth for the current position of the telescope. Goto Alt-Az - Allows you to enter a specific altitude and azimuth position and slew to it. MENU Helpful Hint To store a set of coordinates (R. A. /Dec) permanently into the NexStar database, save it as a User Defined Object as described above. UTILITIES SETUP TIME-SITE ANTI-BACKLASH AZM POSITIVE AZM NEGATIVE ALT POSITIVE ALT NEGATIVE SLEW LIMITS SLEW ALT MAX SLEW ALT MIN DIRECTION BUTTONS AZM BUTTONS ALT BUTTONS LIGHT CONTROL DISPLAY OFF DISPLAY ON KEY PAD OFF KEY PAD ON SELECT MODEL Utility Features Scrolling through the MENU options will also provide access to several advanced utility functions such as anti-backlash compensation and slew limits. Setup Time-Site - Allows the user to customize the NexStar display by changing time and location parameters (such as time zone and daylight savings). Anti-backlash ­ All mechanical gears have a certain amount of backlash or play between the gears. This play is evident by how long it takes for a star to move in the eyepiece when the hand control arrow buttons are pressed (especially when changing directions). The NexStar's anti-backlash features allows the user to compensate for backlash by inputting a value which quickly rewinds the motors just enough to eliminate the play between gears. The amount of compensation needed depends on the slewing rate selected; the slower the slewing rate the longer it will take for the star to appear to move in the eyepiece. You will need to experiment with different values; a value between 20 and 50 is usually best for most visual observing, whereas a higher value may be necessary for photographic guiding. To set the anti-backlash value, scroll down to the anti-backlash option and press ENTER. Enter a value from 0-100 for both azimuth and altitude directions and press ENTER after each one to save these values. NexStar will remember these values and use them each time it is turned on until they are changed. 19 Slew Limits ­ Sets the limits in altitude that the telescope can slew without displaying a warning message first. The NexStar hand control will warn you before allowing the telescope tube to slew to an object below the horizon or slew to an object that is high enough that the tube might hit one of the tripod legs. For example, if you would like to slew to an object that is close to the zenith and are certain that the tube will not hit the tripod legs, you can set the slew limits to 90º in altitude. This will allow the telescope to slew to any object above the horizon without warning. Direction Buttons ­The direction a star moves in the eyepiece varies depending on the accessories being used. [. . . ] Call Celestron at (310) 328-9560 to receive the number to be displayed on the outside of your shipping container. All returns must be accompanied by a written statement setting forth the name, address, and daytime telephone number of the owner, together with a brief description of any claimed defects. Parts or product for which replacement is made shall become the property of Celestron. The customer shall be responsible for all costs of transportation and insurance, both to and from the factory of Celestron, and shall be required to prepay such costs. [. . . ]