Celestron Rowe-Ackermann Schmidt (RASA) 8 "is a professional, ultra-fast (f / 2.0) astrograph designed for taking photographs in a wide field of view with the use of color CCD, CMOS and small mirrorless cameras.
The optical system of this astrograph is a patented construction (patent US 2016/0299331 A1) consisting of a main mirror, a Schmidt corrector and a group of four lenses made of glass with an admixture of rare earth metals. The advantage of this solution is the possibility of obtaining a flat image without optical defects (coma, astigmatism and chromatic aberrations), while maintaining a wide field of view and a very large light (this instrument collects almost 850 times more ¶ light than the human eye). In order to minimize light reflections and to improve the contrast of the image obtained, the lenses were covered with a multilayer StarBright XLT ™ coating, while the main mirror was covered with a reflective layer made of aluminum.
Contrary to other popular telescopes, which show good optical characteristics only for the visible light (400 - 700 nm), the Celestron Rowe-Ackermann Schmidt 8 "astrograph has an extended spectral range, ranging from 400 to 800 nm.
The whole is closed in a durable, aluminum tube equipped with an active cooling system, which significantly improves the process of temperature adaptation, which sometimes takes several hours.
Attention! As the image is captured by a camera placed in the focus of the main mirror, this instrument can only be used in astrophotography. It is not suitable for visual observations.
• Rowe-Ackermann Schmidt optical system with StarBright XLT ™ coating, providing powerful light and aberration-free field of view covering the entire surface of the APS-C sensor
• built-in holder, allowing the installation of filters that reduce light pollution
• stabilized focusing system equipped with a linear ball bearing
• integrated cooling system accelerating the process of temperature adaptation of the telescope
• dovetail CGE mounting rail
• optical system: Rowe-Ackermann Schmidt
• aperture: 203 mm / 8 "
• focal length: 400 mm
• lighted: f / 2.0
• central obstruction (diameter / percentage of aperture): 93 mm / 46%
• spectral range: 400 - 800 nm
• Rayleigh / Dawes resolution: 0.68 "/ 0.57"
• Diameter of the optical window: 46 mm
• diameter of full illumination wheel: 22 mm
• full illumination circle field of view: 3.15 °
• useful field of view diameter: 32 mm
• useful field of view: 4.6 °
• spot size: <4.6 µm RMS
• off-axis illumination: 93% @ 11 mm
• finder: missing
• fokuser: Ultra-Stable Focusing System
• back focus (with attached adapter): 25 mm
• back focus (from the end of the thread): 29 mm
• type of optical system coating: StarBright XLT ™
• main mirror cover: aluminum
• mounting for assembly: dovetail CGE
• tube material: aluminum
• cooling: active, built-in
• Diameter of the optical tube: 235 mm
• length of the optical tube: 628 mm
• weight of the optical tube: 7.7 kg
• CMOS / CCD astronomical cameras with C mount: yes (through the included adapter)
• CMOS / CCD astronomical cameras with M42 mount: yes (through the included adapter and adapter ring available separately)
• CMOS / CCD astronomical cameras with other mounts: yes (through appropriate adapters available separately)
• APS-C (Canon) mirrorless cameras: yes (via a dedicated adapter)
• APS-C (Sony) mirrorless cameras: yes (via a dedicated adapter)
• full-frame mirrorless cameras (Canon): yes (no optimal coverage of the entire frame, a dedicated adapter is required)
• full-frame mirrorless cameras (Sony): yes (no optimal coverage of the entire frame, a dedicated adapter required)
• digital SLR cameras - DSLR: no
• Celestron Rowe-Ackermann Schmidt astrograph (RASA) 8 "
• C-type adapter for mounting a CCD / CMOS camera
• M42 adapter for mounting a CCD / CMOS camera
• battery compartment for the fan