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 astro photography 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 astro photography 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 using an optional equatorial wedge.

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)

There is no exposure determination table to help you get started. The best way to determine exposure length is look at previously published photos to see what film/exposure combinations were used. Or take unguided sample photos of various parts of the sky while the drive is running. Always take exposures of various lengths to determine the best exposure time.

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Celestron 8i manual
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8i specifications

The Celestron 8i is a highly regarded telescope that has made a significant impact in the world of amateur astronomy, renowned for its performance, advanced features, and user-friendly design. Part of Celestron's Advanced Series, the 8i model boasts an impressive 8-inch Schmidt-Cassegrain optical system, which combines the advantages of a large aperture with a compact design. This allows enthusiasts to explore celestial objects with greater clarity, providing bright, sharp images of planets, star clusters, and nebulae.

One of the standout features of the Celestron 8i is its Fast Star capability, which allows for rapid imaging of celestial objects. Coupled with its advanced StarBright XLT coatings, this system enhances light transmission and increases contrast, resulting in a more vivid and detailed observation experience. This combination makes it an ideal choice for both novice and experienced astronomers who seek high-quality visuals of deep-sky objects.

The telescope's computer-controlled GoTo mount simplifies the process of locating and tracking celestial objects. With the push of a button, users can easily access a database containing over 40,000 astronomical objects, allowing for an effortless stargazing experience. The Celestron 8i also features an intuitive hand controller that enables users to customize their observations and seamlessly navigate the night sky.

The Celestron 8i is designed for portability, despite its robust optical performance. Weighing in at around 45 pounds, it is relatively easy to transport to different observing locations. The telescope's sturdy construction ensures stability while providing ease of setup, facilitating a hassle-free stargazing experience.

In terms of accessories, the 8i comes equipped with a 25mm eyepiece, offering a moderate magnification that is perfect for a variety of targets. Additionally, users can expand their observing capabilities with optional eyepieces, filters, and focal reducers, catering to both visual and astrophotography pursuits.

Overall, the Celestron 8i stands out as a versatile and powerful telescope that meets the needs of amateur astronomers at various skill levels. With its advanced features, superior optics, and impressive usability, the 8i offers a unique and rewarding experience under the night sky. Whether for planetary observation or deep-sky exploration, the Celestron 8i remains a top choice for astronomy enthusiasts.
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