Telescope-Astrographs-Celestron 8″ Rowe-Ackermann Schmidt Astrograph OTA Imaging Kit

Unique Optical Design
The RASA optical design consists of a Schmidt corrector, primary mirror, lens group, and optical window. The 4-element lens group uses rare-earth elements. Contrary to many telescopes that only offer great performance within the visible spectrum (400 nm to 700 nm), the 8″ RASA’s optical system has been designed for strong performance that covers a wider 390 nm to 800 nm spectral range. This design lets in more sharply focused light transmitted by your target astronomical object to make it to your image. With many imaging systems, adding an extra piece of flat glass such as a filter will not alter optical performance. However, that is not the case with super fast optical systems like the RASA. Celestron’s engineers have addressed this by designing the RASA with a removable optical window to allow peak optical performance to be maintained if a filter is added or if a camera has its own optical window. Celestron StarBright XLT coatings cover all refractive optical surfaces, while enhanced aluminum coatings cover the primary mirror. This keeps light transmission high throughout the whole optical system.

Optimized for Smaller Cameras
Contrary to larger Rowe-Ackermann Schmidt Astrographs that are compatible with DSLR and large CCD cameras, the 8″ version was designed with regards to color astronomical CMOS cameras, smaller CCD cameras, and mirrorless cameras. This telescope is not suitable for use with standard DSLR cameras. Optimized for up to 22 mm diagonal sensors, the 8″ RASA also offers sufficient performance with sensors up to 32 mm diagonal. Many mirrorless cameras use APS-C sized sensors that would be an excellent option. Sensors that have a 42 mm diagonal, like full frame cameras, are also compatible but performance will suffer at the edges of the sensor while field illumination is decreased. Furthermore, Celestron does not recommend pairing the 8″ RASA with any 4″ diameter or larger camera body. Due to its extremely fast f/2 optical system, astrophotographers can use minimal exposure times with the 8″ RASA to capture enhanced detail in dim targets. When employed in conjunction with sensitive cameras and the appropriate “live stacking” software, the 8″ RASA is capable of delivering a virtual real-time observing experience. Instantly view images on a computer with more brightness and detail than can be viewed with the naked eye using much larger telescopes.

Ultra-Stable Focusing
The Celestron 8″ RASA focuser design alleviates lateral movement of the primary mirror while the telescope is focusing, slewing, or tracking. This makes focusing easier, more stable, and accurate than ever before. At the core of this Ultra-Stable Focus System is two sets of precision bearings that have been precisely aligned and tested during construction for results that are guaranteed to be optimal.

Included H-alpha, H-beta, OIII Imaging Filter
Get the most out of your deep sky nebulae astro-photos with this Celestron combination H-Alpha-H-Beta-OIII Imaging Filter designed specifically for the 8″ RASA. With this filter, emission nebulae light is allowed to pass while light from polluted skies and other unwanted sources is rejected, resulting in enhanced contrast for eye-catching image detail when viewed against the black sky background. The reason this filter is able to block light pollution with such precision is due to these emissions being produced mainly at distinct wavelengths. “Bad” light pollution from critical wavelengths is prohibited from effecting the image while “good” wavelengths from emission nebula are permitted to pass through to the lens. The enhanced contrast will be obvious, even for backyard astrophotographers contending with heavily light polluted skies. Additionally, with transmission at essential wavelengths so high, the background sky might be darker, but nebula brightness will remain intact.

Included Light Pollution Imaging Filter
The quality of astronomical image contrast suffers substantially when light pollution levels are too high. With ultra fast instruments like the 8″ RASA, this is particularly true since the sky background saturated extremely quickly. Light pollution “noise” overpowers the “signal” from your target celestial object to make capturing strong detailed images a much harder task. Light from some of the most frequent light pollution culprits in the visual spectrum (400-700 nm) such as high and low pressure sodium-vapor and mercury-vapor streetlamps, as well as natural airglow resulting from oxygen in the atmosphere is blocked by this Light Pollution Imaging (LPI) Filter for 8″ RASA. This filter fits directly into the internal filter mount in the 8″ RASA’s front lens cell where the optical window normally mounts. By removing the clear window and replacing it with the LPI filter, optical performance for the entire system is preserved. By strategically blocking these wavelengths, this filter greatly reduces the effects of light pollution without degrading overall image quality.