Orion XT4.5 instruction manual Sit Down or Stand Up?, Altitude and Azimuth, Focusing the Telescope

XT4.5 during the day, before observing astronomical objects at night. This way you will not have to fumble around trying to orient yourself in the dark! Find a spot outdoors where you have plenty of room to move around the telescope, and where you have a clear view of some object or vista that is at least 1/4-mile away. It is not critical that the base be exactly level, but it should be placed on somewhat flat ground or pavement to ensure smooth movement of the telescope.

Keep in mind that the SkyQuest XT4.5 was designed specif- ically for visual observation of astronomical objects in the night sky. Like all Dobsonians, it is not well-suited for daytime, terrestrial usage. This is due to the inverted images the Newtonian reflector optics provide and the low eyepiece height when pointed near the horizon. We recommend get- ting started during the day with the telescope, but remember that this is not the intended use. If you find that you want to do more daytime viewing of landscapes and vistas, you may want to consider purchasing a spotting scope.

Remember, never point the telescope at or near the Sun

c.

a.b.

Figure 9:(a) Many people find the SkyQuest XT4.5 convenient to use while sitting. (b) You can use the telescope while standing by placing it on a sturdy table. (c) If the table is too tall, try something a bit shorter, like a milk crate.

without using a proper solar filter over the front aperture!

Sit Down or Stand Up?

One of the great assets of the SkyQuest XT4.5 is its extreme- ly portable size. Due to its overall short height, most adults will find that observing while sitting on a chair or stool is most comfortable. If wanting to stand, a sturdy table of appropriate height will provide an adequate platform on which to place the telescope. Other platforms, such as a milk crate, can also be employed in order to achieve a range of eyepiece heights. (Figure 9)

Younger children will find that the telescope is a perfect height for them to use while standing; this is one of the reasons that it is ideal for budding young astronomers.

Altitude and Azimuth

The Dobsonian base of the SkyQuest XT4.5 permits motion of the telescope along two axes: altitude (up/down) and azimuth (left/right) (see Figure 10). This is very convenient, since up/down and left/right are the most “natural” ways that people aim. As a result, pointing the telescope is exceptionally easy.

Simply take hold of the telescope (Figure 11) and move it left

Altitude

Azimuth

Figure 10. The SkyQuest has two axes of motion: altitude (up/down) and azimuth (left/right).

or right so the base rotates about its central azimuth bolt, and move it up or down so the altitude side bearings rotate in the base’s cradle. Both motions can be made simultaneously and in a continuous manner for easy aiming. Move the telescope gently - let it glide. In this way you can point the telescope to any position in the night sky, from horizon to horizon.

One of the unique features of the SkyQuest XT is the Navigation Knob located underneath the telescope tube near the open end. This knob makes for easy, smooth movement of the telescope. You can use it to move the telescope in both the azimuth and altitude directions.

You may find it convenient to hold your other hand near the

Figure 11: Try grasping the telescope as shown for easiest pointing. The left hand uses the Navigation Knob as a “handle”, while the right hand is on the rear of the tube.

rear of the telescope tube to steady it while moving and aim- ing the telescope.

Focusing the Telescope

Insert the low-power 25mm eyepiece into the focuser and secure with the thumbscrew. Move the telescope so the front

7