Celestial Sphere An imaginary sphere surrounding the Earth, concentric with the Earth's center. Collimation The act of putting a telescope's optics into perfect alignment. D - Declination (DEC) The angular distance of a celestial body north or south of the celestial equator. It may be said to correspond to latitude on the surface of the Earth. E - Ecliptic The projection of the Earth's orbit on to the celestial sphere. It may also be defined as "the apparent yearly path of the Sun against the st

If you look into the eyepiece adapter (without an eyepiece) at the top of the focuser, this is what you should see. If the reflection of your eye is off center, then collimation is necessary. Adjustments to the collimation of the telescope can be made by turning the collimation adjustment knobs located at the rear of the optical tube. First loosen the three Phillips head screws on the rear cell of the tube. Turn each collimation knobs, one at a time, until the reflected image of your eye in the

28 Observing the Planets................................................................................................................................................ 28 Planetary Observing Hints ........................................................................................................................................ 28 Observing the Sun.................................................................................................................................................

Filter Limits – When an alignment is complete, the NexStar automatically knows which celestial objects are above the horizon. As a result, when scrolling through the database lists (or selecting the Tour function), the NexStar hand control will display only those objects that are known to be above the horizon when you are observing. You can customize the object database by selecting altitude limits that are appropriate for your location and situation. For example, if you are observing from a mou

Using the example in the previous section, we can determine the field of view using the same 25mm eyepiece. The 25mm eyepiece has an apparent field of view of 50°. Divide the 50° by the magnification, which is 40 power. This yields an actual field of view of 1.25°. To convert degrees to feet at 1,000 yards, which is more useful for terrestrial observing, simply multiply by 52.5. Continuing with our example, multiply the angular field 1.4° by 52.5. This produces a linear field width of 66 feet at

5. The stores the user-defined objects in two and Press 1 for the format and 2 for the 6. By default the will display the or coordinates where the telescope is currently pointed. In the case of format, the coordinate readout will be similar to this: which means 22 hours and 46.1 minutes in R.A. and in Change the coordinates using the numeric keypad and scroll keys. Use the RIGHT or LEFT directional keys to move the cursor to the next or previous digit. Press ENTER to save. If the coordinate ente