A telescope is an instrument that collects and focuses light. The nature of the optical design determines how the light is focused. Some telescopes, known as refractors, use lenses. Other telescopes, known as reflectors, use mirrors. A Newtonian reflector uses a single concave mirror as its primary. Light enters the tube traveling to the mirror at the back end. There light is bent forward in the tube to a single point, its focal point. Since putting your head in front of the telescope to look at the image with an eyepiece would keep the reflector from working, a flat mirror called a diagonal intercepts the light and points it out the side of the tube at right angles to the tube. The eyepiece is placed there for easy viewing.

Newtonian Reflector telescopes replace heavy lenses with mirrors to collect and focus the light, providing much more light-gathering power for the dollar. Because the light path is intercepted and reflected out to the side, you can have focal lengths up to 1000mm and still enjoy a telescope that is relatively compact and portable. A Newtonian Reflector telescope offers such impressive light-gathering characteristics you can take a serious interest in deep space astronomy even on a modest budget. Newtonian Reflector telescopes do require more care and maintenance because the primary mirror is exposed to air and dust. However, this small drawback does not hamper this type of telescope’s popularity with those who want an economical telescope that can still resolve faint, distant objects.

Figure 4-1

A cutaway view of the light path of the Newtonian optical design

Image Orientation

Newtonian reflectors produce a right-side-up image but the image will appear rotated based on the location of the eyepiece holder in relation to the ground. Newtonian reflectors are best for astronomical use where right-side-up does not matter.

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Celestron C10-N, C8-NGT manual Image Orientation
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C10-N, C8-NGT, C8-N specifications

The Celestron C8-NGT, C8-N, and C10-N telescopes represent a range of superior astronomical instruments that cater to both novice and experienced astronomers alike. Among these, the C8-NGT combines the advanced features of a computerized telescope with the simplicity of a Newtonian design. Its 8-inch aperture allows for impressive light-gathering capability, making it ideal for observing distant galaxies, star clusters, and nebulae. The GoTo mount enhances usability, enabling users to locate celestial objects effortlessly with the push of a button.

The C8-N, also featuring an 8-inch aperture, stands out with its open tube design that provides maximum airflow and minimizes thermal issues, ensuring optimal performance. The scope is designed with user-friendly adjustments and a sturdy equatorial mount, allowing for smooth tracking of celestial objects. Its high-quality optics provide sharp images and incredible clarity, making it suitable for both planetary and deep-sky observations.

On the other hand, the C10-N is the largest in this lineup, boasting a 10-inch aperture that dramatically enhances its light-gathering ability. This larger size makes the C10-N a powerhouse for serious astronomers looking to explore fainter objects and intricate details within astronomical features. Like the C8-N, it employs a Newtonian reflector design, allowing for a compact and manageable profile, while still providing stunning visuals across a range of celestial bodies.

All three telescopes incorporate Celestron's commitment to creating durable, robust, and user-friendly systems. They utilize premium quality glass and optics, which are coated to improve light transmission and provide high-contrast images. Additionally, they are designed with ease of assembly and portability in mind, catering to astronomers who enjoy observing in various locations.

The Celestron C8-NGT, C8-N, and C10-N serve as excellent options for anyone looking to deepen their astronomical pursuits, offering a blend of advanced technology, high-quality optical performance, and user-friendly features. Whether you're a beginner eager to peer into the wonders of the universe or an experienced observer at the peak of your skills, these telescopes offer a remarkable means to expand your cosmic horizons. With precision engineering and thoughtful design, Celestron continues to be a trusted name in the world of astronomy.
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