The iconic 8-inch Schmidt-Cassegrain has been known for decades as Celestron’s most beloved telescope. Now beginner to intermediate astroimagers can have their own “C-8” at an extremely affordable price. This classic design has been upgraded with our StarBright XLT coatings for maximum light transmission. Combined with our fully featured Advanced VX mount, you have a setup that is ready for both imaging and visual observing.
About the Mount
The new Advanced VX mount was specifically designed to provide optimum imaging performance for smaller telescopes. Now your smaller telescope can take advantage of All-Star Polar Alignment and autoguider support. You’ll be able to track through long exposures using permanently programmable periodic error correction. Image across the meridian without doing a meridian flip, so you can seamlessly image the best part of night sky. Advanced VX features significantly larger base castings than our previous design, improving stability under heavier loads. Improved motors offer more torque and can handle slight load imbalances with ease.
About Celestron Schmidt-Cassegrain Telescopes
Celestron’s excellent Schmidt-Cassegrain telescopes are compact and portable and represent the best all-purpose design for a wide variety of uses from terrestrial and deep sky viewing to astrophotography.
Catadioptrics use a combination of mirrors and lenses to "fold" (reflect) the light path and form an image. In a Schmidt-Cassegrain, the light enters through a thin aspheric Schmidt correcting lens. It then strikes the spherical primary mirror. It is reflected back up the tube and intercepted by a small secondary mirror which reflects the light out an opening in the rear of the instrument where the image is formed at the eyepiece.
Catadioptrics are the most popular and most modern type of telescope optical design and are marketed throughout the world in 3.5" and larger apertures. Catadioptric telescopes combine the practical advantages of lenses and mirrors while eliminating their disadvantages. They offer the clarity and contrast of refractors with the low aberration of reflectors. Catadioptrics have an average focal ratio of f/10, which is wide enough for all types of photography. They are also easier to maintain because all optical elements are solidly mounted and rigidly collimated. Catadioptric telescopes provide the best possible combination of light gathering power, long focal length, portability and affordability.
Celestron All-Star Polar Alignment Technology
All-Star Polar Alignment Technology
German Equatorial Mounts (GEM) have long since been recognized as the mount of choice for astrophotography. Needing to track in only one axis for long exposures; adjustable counterweights and tube position for perfect balance, the GEM has few short comings when it comes to imaging. In order to do long-exposure astro-imaging, an equatorially aligned telescope is needed to allow your telescope to properly track the motion of the sky. However accurate tracking still depends on an accurate polar alignment. Even with a visible star very near the North Celestial Pole (NCP), the true celestial pole can be a very elusive place to find without assistance.
Now select Celestron mounts can utilize a new innovative Polar alignment procedure called All-Star™. All-Star allows users to choose any bright star, while the software calculates and assists with polar alignment.
Here's how it works.
Once your telescope is aligned with two bright star, All-Star allows you to choose any bright star listed in the NexStar hand control to assist in accurately aligning your telescope's mount with the North Celestial Pole. Using the telescope's Sync function, the mount is able to point and center a bright star with a high degree of accuracy. Once centered, the mount will point the telescope to the exact position that the star should be if the mount were precisely polar aligned. By simply adjusting the mounts altitude and azimuth controls to re-center the star in the center of the eyepiece, you are actually moving the mounts polar axis to the exact position of the North Celestial Pole.
Can I use Polaris to polar align my telescope?
Since Polaris is very close to the NCP and not very bright, it is actually not a recommended star for the "All-Star" method. The advantages of being able to use stars other than Polaris are two fold:
Polaris is not always visible. So not only can you use a variety of other stars but they are also brighter and more prominent.
The star you choose will be farther away from the NCP thus allowing for greater accuracy when centering the star in your eyepiece.
Which stars are best to use for polar aligning?
For best results choose a bright alignment star that is near the Meridian, preferably close to the celestial equator. Try to avoid stars that are close to the west/east horizon or directly overhead because they can be more difficult to center using the mount's altitude and azimuth controls. Also stars too near the celestial pole are less accurate than those further away.
Will I lose my alignment after I polar align?
No, the mount will retain its alignment but some amount of accuracy may be compromised depending on how much the mount has been moved during polar alignment. Although the telscopes tracking may be very good, pointing accuracy may need to be improved, especially if you are trying to located small objects on a ccd chip.
What are the steps to polar align my telescope using "All-Star" polar alignment?