There are several techniques for this type of photography, and the one chosen will determine the standard accessories needed. The best method for long exposure deep sky astrophotography is with an off-axis guider. This device allows you to photograph and guide through the telescope simultaneously. Celestron offers a very special and advanced off- axis guider, called the Radial Guider (#94176). In addition, you will need a T-Ring to attach your camera to the Radial Guider.

Other equipment needs include a guiding eyepiece. Unlike other forms of astrophotography which allows for fairly loose guiding, prime focus requires meticulous guiding for long periods. To accomplish this you need a guiding ocular with an illuminated reticle to monitor your guide star. For this purpose, Celestron offers the Micro Guide Eyepiece (#94171) Here is a brief summary of the technique.

1.Polar align the telescope. For more information on polar aligning, see the Polar Alignment section earlier in the manual.

2.Remove all visual accessories.

3.Thread the Radial Guider onto your telescope.

4.Thread the T-Ring onto the Radial Guider.

5.Mount your camera body onto the T-Ring the same as you would any other lens.

6.Set the shutter speed to the "B" setting.

7.Focus the telescope on a star.

8.Center your subject in the field of your camera.

9.Find a suitable guide star in the telescope field. This can be the most time consuming process.

10.Open the shutter using a cable release.

11.Monitor your guide star for the duration of the exposure using the buttons on the hand controller to make the needed corrections.

12.Close the camera's shutter.

When getting started, use fast films to record as much detail in the shortest possible time. Here are proven recommendations:

•Ektar 1000 (color print)

•Konica 3200 (color print)

•Fujichrome 1600D (color slide)

•3M 1000 (color slide)

•Scotchchrome 400

•T-Max 3200 (black and white print)

•T-Max 400 (black and white print)

As you perfect your technique, try specialized films, that is films that are designed or specially treated for celestial photography. Here are some popular choices:

•Ektar 125 (color print)

•Fujichrome 100D (color slide)

•Tech Pan, gas hypered (black and white print)

•T-Max 400 (black and white print)

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Celestron C9.25-S, C8-S, C5-S instruction manual
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C9.25-S, C5-S, C8-S specifications

Celestron, a leader in the field of amateur and professional astronomy, offers a range of telescopes ideal for both novices and experienced stargazers. Among their most celebrated models are the C8-S, C5-S, and C9.25-S, each designed with unique features and technologies that enhance the observational experience.

The Celestron C8-S is an iconic telescope known for its 8-inch aperture. This Schmidt-Cassegrain design combines a compact form factor with a powerful light-gathering capability, making it perfect for deep-sky observing. Its optical tube has a focal length of 2032mm, providing an excellent balance of wide field viewing and high magnification. The C8-S features Celestron's StarBright XLT optical coating, enhancing light transmission and contrast, ensuring that even faint objects are visible. With compatibility for various accessories and a sturdy mount, the C8-S stands as a versatile option for different observing styles.

Moving to the C5-S, this model boasts a 5-inch aperture while maintains a compact and portable design. It is particularly popular among travelers and casual astronomers who value convenience without compromising on quality. The C5-S also employs the Schmidt-Cassegrain design, providing sharp images and improved color correction. With its shorter focal length of 1250mm, the C5-S excels in both planetary and deep-sky observation. The telescope's lightweight build makes it easy to transport, while the integrated optical systems ensure a clear view of celestial objects.

The C9.25-S represents a step up in performance, featuring a 9.25-inch aperture that captures more light than its smaller counterparts. This telescope offers a versatile focal length of 2350mm, allowing for impressive high-power planetary views, as well as detailed observations of deep-sky objects. The C9.25-S utilizes a unique StarBright XLT coating and features advanced optics that minimize optical distortion, resulting in sharp, high-contrast images. It is equipped with a sturdy mount that ensures stability during extended observation sessions.

All three models are compatible with Celestron's advanced computer-driven mount systems, allowing for effortless tracking and alignment. With built-in features such as GoTo technology, users can easily locate thousands of celestial objects with the touch of a button. This combination of advanced optics, portability, and user-friendly technology makes the Celestron C8-S, C5-S, and C9.25-S excellent choices for anyone looking to explore the cosmos more deeply. Whether for casual stargazing or serious astronomical study, these telescopes deliver exceptional performance to meet a variety of needs.
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