Installing the Eyepieces

The eyepiece, or ocular as it is also called, is an optical element that magnifies the image focused by the telescope. Without the eyepiece it would be impossible to use the telescope visually. The eyepiece fits directly into the focuser. To attach an ocular:

1.Loosen the set screw on the eyepiece adapter so that it does not obstruct the inner diameter of the barrel.

2.Slide the chrome portion of the eyepiece into the focuser.

3.Tighten the set screw to hold the eyepiece in place.

To remove the eyepiece, loosen the set screw on the focuser and slide the eyepiece out. You can replace it with another ocular.

Focuser Tension

Screw

1 ¼" Eyepiece

Adapter

 

 

 

T-Adapter

 

 

 

Thread

 

 

 

2" Focuser

 

 

Focuser Knob

 

 

 

Barrel

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 2-11

Eyepieces are commonly referred to by focal length and barrel diameter. The focal length of each eyepiece is printed on the eyepiece barrel. The longer the focal length (i.e., the larger the number) the lower the eyepiece magnification (i.e., power) and the shorter the focal length (i.e., the smaller the number) the higher the magnification. Generally, you will use low-to-moderate power when viewing. For more information on how to determine power, see the section on “Calculating Magnification.”

Your telescope can use eyepieces with both a 1-1/4" barrel diameter and 2" barrel diameter. To use a 2" barrel eyepiece, the 1 1/4" eyepiece adapter must first be removed. To do this, simply loosen the two chrome thumbscrews located around the focuser barrel (see figure 2-11) and remove the 1 1/4" adapter. Once removed, a 2" eyepiece or accessory can be inserted directly into the focuser barrel and secured with the two thumb screws.

Balancing the Tube in R.A.

To eliminate undue stress on the mount, the telescope should be properly balanced around the polar axis. In addition, proper balancing is crucial for accurate tracking if using an optional motor drive. To balance the mount:

1.Release the R.A. Clamp (see figure 2-15) and position the telescope off to one side of the mount (make sure that the mounting bracket screw is tight). The counterweight bar will extend horizontally on the opposite side of the mount (see figure 2-12).

2.Release the telescope — GRADUALLY — to see which way the telescope “rolls.”

3.Loosen the set screw on the counterweight.

4.Move the counterweight to a point where it balances the telescope (i.e., it remains stationary when the R.A. clamp is released).

5.Tighten the set screw to hold the counterweight(s) in place.

These are general balance instructions and will reduce undue stress on the mount. When taking astrophotographs, this balance process should be done for the specific area at which the telescope is pointing.

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Celestron C100ED-R, C80ED-R manual Balancing the Tube in R.A, Installing the Eyepieces
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C100ED-R, C80ED-R specifications

Celestron, a renowned name in the field of astronomy, has built a reputation for producing high-quality telescopes that are accessible to both amateur and professional astronomers alike. Among their impressive lineup are the Celestron C100ED-R and C80ED-R telescopes, both of which are crafted to enhance the observational experience through advanced optics and user-friendly features.

The Celestron C100ED-R, a 100mm refractor telescope, stands out for its premium extra-low dispersion (ED) glass, which delivers exceptional color correction and sharpness. This ED technology minimizes chromatic aberration, ensuring clearer and more colorful celestial images. The telescope boasts a focal length of 900mm, resulting in a focal ratio of f/9. This combination allows for high magnification capabilities while maintaining a wide field of view, perfect for observing both planetary details and deep-sky objects. The robust, yet lightweight design of the C100ED-R makes it highly portable, allowing for convenient stargazing sessions.

On the other hand, the C80ED-R is a 80mm refractor telescope that combines portability with performance. With its 600mm focal length and f/7.5 focal ratio, the C80ED-R is ideal for wide-field observations, making it easy to explore star clusters and large nebulae. Like its larger counterpart, the C80ED-R features ED glass, which prevents color distortion, allowing for clear and crisp images. The compact design is perfect for those who wish to travel or set up in tight spaces, ensuring that astronomy remains accessible.

Both telescopes are equipped with high-quality multi-coated optics that enhance light transmission, resulting in brighter images. Celestron's user-friendly mounting systems allow for smooth tracking of celestial objects, making it easier to follow objects as they move across the night sky. Additionally, these telescopes come with a variety of accessories, including premium eyepieces that enhance the viewing experience, and sturdy tripods that provide stable support during observations.

In summary, both the Celestron C100ED-R and C80ED-R offer exceptional features that cater to a variety of observing needs. With advanced ED optics, high-quality construction, and portability, they are ideal choices for aspiring astronomers looking to explore the wonders of the universe. Whether you're interested in planetary observation or deep-sky exploration, Celestron's C100ED-R and C80ED-R will not disappoint.
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