Celestron RASA 8 - 8" Rowe-Ackermann Schmidt Astrograph OTA
Engineered for Excellence: The Celestron RASA 8!
If you’re in the market to elevate your astrophotography game, the Rowe-Ackermann Schmidt Astrograph from Celestron is the solution. Offering an unbeatable native focal ratio of f/2, this Celestron 8” RASA is an astrophotographer’s dream! Couple this unrivaled light gathering power with the superior optical technology from Celestron and enjoy bright, astigmatism-free images. Perfect for deep space enthusiasts, the focal length of 400 mm is great for capturing large portions of the night sky in a single frame. Whether you plan to reveal intricate dust lanes within galaxies or exquisite structure in nebulae, this RASA 8 from Celestron is sure to take your images to the next level.
Designed for those serious about astroimaging, Celestron has carefully crafted this OTA to feature everything an astrophotographer wishes for. Not only is the light gathering power and speed impressive, but the optical elements within this RASA 8 provide an inherent flat field, razor sharp stars, and photos absent of aberration. In addition to this, rest assured knowing every bit of detail is being collected as the patented CelestronStarBright XLT coatings ensure maximum light transmission to your camera sensor. Celestron has also furnished their RASA series with mechanisms such as a smooth internal focuser and an integrated telescope cooling system to enhance your astrophotography experience even further. With qualities like these, Celestron delivers an astrograph that's a cut above the rest!
The Unmatched Optical Design of the Celestron RASA
Taking the already incredible astrophotography performance of the Schmidt-Cassegrain optical design up a notch, Celestron has developed the Rowe-Ackermann Schmidt Astrograph for those serious in their imaging endeavors. RASA telescopes consist of a lens group, a Schmidt corrector plate, a primary mirror, and an optical window. After passing through the Schmidt corrector plate, the incoming light hits the primary mirror, then is redirected to the lens group. This lens group is composed of four elements of rare-earth material, correcting for field curvature, false color and aberration, and provides a significant reduction in vignetting. When it comes to speed, the RASA does not disappoint. These patented Rowe-Ackermann Schmidt Astrographs feature a native focal ratio of f/2—an outstanding improvement from standard f/10 Schmidt-Cassegrain telescopes! With a focal ratio this low, more light is able to be collected on your camera sensor in less time. This results in brighter, more detailed images and projects to be completed far quicker. For instance, a 30 second exposure with the RASA is equivalent in brightness to a ~10 minute exposure with an f/10 SCT. That’s 20x as fast! In addition to faster collection of signal, RASA optical assemblies also offer an increased range of signal collection. A large majority of telescopes deliver peak performance in the visible spectrum (400 nm to 700 nm), while the RASA excels within a wider spectral range of 390 nm to 800 nm. This increase allows for a greater collection of light on celestial bodies. To enhance performance even further, Celestron has included enhanced aluminum coatings on the primary mirror, as well as their patented StarBright XLT coatings on the refractor elements for maximum light transmission to your camera sensor.
A Feature-Rich, Light Gathering Powerhouse
Celestron has loaded this telescope with qualities that are sure to help you reach new heights within your astrophotography journey. The unrivaled optical design allows you to collect bright, beautiful images, the added mechanics improve your image quality even more, and the plethora of optional and included accessories further elevate your nights under the stars. Thanks to the ingenuity from Celestron, you’re set up for success! Read more about this world-renowned astrograph below.
Large 8” Optics
This RASA 8 features a focal length of 400 mm, making it well suited for wide shots of your favorite nebulae! Capture vast portions of the night sky, such as the busy Sagittarius constellation, the hydrogen-rich Cygnus region, the Orion Molecular Cloud Complex, and plenty more. With the large 8” of aperture and wickedly fast f/2 focal ratio, copious amounts of photons are collected in a short amount of time. This feature is wonderful for completing imaging projects in a timely manner, especially for those who have limited clear sky time. In addition to this, the fast light gathering power and wide field of view is much less demanding on the telescope mount. In some cases, autoguiding may not even be required for sharp images!
Innovative Architecture
As the optics themselves perform exceptionally well, it’s necessary to have systems in place that help maximize image quality. With this in mind, Celestron has furnished the RASA optical assemblies with an internal focuser as well as a built-in fan! The Ultra-Stable Focus System (USFS) houses a precision linear ball bearing for reduced image shift while focusing. In addition to this, the upgraded focus design reduces the detrimental effects of mirror flop—that is—the unwanted movement of the primary mirror during different telescope positions. To aid in ventilation and healthy airflow, the 12V DC MagLev fan helps expel hot air from inside of the tube. This ensures the image is not degraded by distortions from heat plumes by bringing the optics down to ambient temperature.
Compatible With A Wide Range of Cameras
This 8” RASA is created specifically for astrophotography and functions solely as an astrograph, meaning it cannot be used visually. While optimized for sensors with a 22 mm diagonal, the RASA 8 offers a well-corrected field of view for sensors with up to a 32 mm diagonal. This means even those with large APS-C sized sensors can benefit from this outstanding optical design. DSLRs are not compatible with the 8” RASA, and other cameras with bodies larger than 4” are not recommended due to the decrease in field illumination. Two adapters are included within this package: an M42 adapter for use with the majority of cameras with T-threads, and a C-thread camera adapter. If utilizing the M42 camera adapter, 25 mm of back spacing is required to reach proper focus. The addition of user supplied extension rings may be necessary to reach this distance. If the C-thread adapter and your camera meets the C-thread standard of 17.5mm of back focus, no additional spacers are needed to reach proper focus. If you wish to utilize your mirrorless camera with this RASA 8, check out the Sony and Canon adapters we carry here at High Point Scientific.
Upgrade Your RASA With A Host of Additions
To help you get the most out of your RASA experience, Celestron has developed numerous accessories to pair with this 8” astrograph. If you’re in need of a dew solution, the addition of the 8” Dew Ring is a great choice! By warming the front corrector plate just enough, pesky dew is eliminated. To help the nebulae within your images stand out, insert the H-alpha H-Alpha-H-Beta-OIII Narrowband Filter within your imaging train. This filter works to enhance nebulosity by darkening the sky background and improving contrast. Wanting to streamline your setup routine? The Celestron Focus Motor offers hands-free, automatic focusing. With the help of software, this electronic focuser finds the exact focal point of your optics, making it a breeze to get ready for a night of imaging.
Everything You Need Right Out of the Box
As stated above, this RASA 8 comes readied with an M42 camera adapter as well as a C-thread camera adapter. These two inclusions make camera attachment quick and easy and help you get out and under the stars in no time! Also added is a CGE (Losmandy-D) style dovetail bar for mounting atop a wide variety of equatorial mounts. To make powering the built-in fan effortless, Celestron has added a battery pack that plugs into the 12V power port. Eight AA batteries (not included) power this fan, providing a convenient, compact power system.
Astronomy Hub: Your one-stop-shop for Astrophotography Knowledge!
Our Gear Experts have compiled a wealth of information to help expand your astrophotography knowledge! Below you’ll find links to articles, videos and "how-to" guides. Just one more reason that our Astronomy Hub is a one-stop-shop for all your astronomy and astrophotography needs!
| Autoguiding |
| Choosing the Best Deep Sky Camera |
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