Celestron NexStar 90SLT Computerized Telescope NexStar SLT Series MAKs Manual - Page 19

Direction Buttons The NexStar has four direction buttons in the center of the hand control which controls the telescope motion in altitude (up and down) and azimuth (left and right). The telescope can be controlled at nine different speed rates. Rate Button 1 = 2x 2 = 4x 3 = 8x 4 = 16x 5 = 32x 6 = 64x 7 = 1º / sec 8 = 2º / sec 9 = 3º / sec Nine available slew speeds Pressing the RATE key (11) allows you to instantly change the speed rate of the motors from high speed slew rate to precise guiding rate or anywhere in between. Each rate corresponds to a number on the hand controller key pad. The number 9 is the fastest rate (approximately 4º per second, depending on power source) and is used for slewing between objects and locating alignment stars. The number 1 on the hand control is the slowest rate (2x sidereal) and can be used for accurate centering of objects in the eyepiece. To change the speed rate of the motors:  Press the RATE key on the hand control. The LCD will display the current speed rate.  Press the number on the hand control that corresponds to the desired speed. The hand control has a "double button" feature that allows you to instantly speed up the motors without having to choose a speed rate. To use this feature, simply press the arrow button that corresponds to the direction that you want to move the telescope. While holding that button down, press the opposite directional button. This will increase the speed to the maximum slew rate. When using the Up and Down buttons on the NexStar, the slower slew rates (6 and lower) move the motors in the opposite direction than the faster slew rates (7- 9). This is done so that an object will move in the appropriate direction when looking into the eyepiece (i.e. pressing the up arrow button will move the star upwards in the field of view of the eyepiece). However, if any of the slower slew rates (rate 6 and below) are used to center an object in the Star Pointer, you may need to press the opposite directional button to make the telescope move in the correct direction. Set Up Procedures The NexStar contains many user defined setup functions designed to give the user control over the telescope's many advanced features. All of the set up and utility features can be accessed by pressing the MENU key and scrolling through the options: Tracking Mode Once the NexStar is aligned the tracking motors will automatically turn on and begin tracking the sky. However, the tracking can be turned off for terrestrial use: Alt-Az This is the default tracking rate and is used when the telescope has been properly aligned. EQ North Used to track the sky when the telescope is polar aligned using an equatorial wedge in the Northern Hemisphere. EQ South Used to track the sky when the telescope is polar aligned using an equatorial wedge in the Southern Hemisphere. Off When using the telescope for terrestrial (land) observation the tracking can be turned off so that the telescope never moves. Note: EQ North and EQ South tracking modes are only needed with telescopes that can be polar aligned. The NexStar SLT series are exclusively Alt-Az mounted telescopes and do not require equatorial tracking. 19