Celestron 8" RASA Rowe-Ackermann Schmidt Astrograph Telescope with CGX Goto EQ Mount

Description
Customer Reviews

Sky & Telescope’s Hot Products 2019 Award

"Incredibly fast optical speeds allow deep-sky imaging with short exposures, opening up a new world of scientific- and recreational-astrophotography possibilities."

Product Highlights

Patented Catadioptric Astrograph Design
400mm Focal Length/ f/2.0 Focal Ratio
StarBright XLT Optical Coating System
4-Element Rare-Earth Optical Glass
Includes Photo & Video T-Adapters
CGX Motorized GoTo Mount with Tripod
High-Torque Dual-Axis Servo Motors
NexStar+ Computer Hand Controller
Backlash Compensation and PPEC
Not Recommended for Visual Use

The Celestron 8" f/2.0 Rowe-Ackermann Schmidt Astrograph (RASA) is specifically designed for astrophotography and astro-imaging with a large aperture and fast focal ratio. Using four-element rare-earth optical glass lenses ensures accurate color rendition and eliminates aberrations such as coma and field curvatures. The improved StarBright XLT multi-coating system, which includes anti-reflection coatings on the lenses and highly reflective coatings on the mirrors, increases light transmission throughout the entire optical path. An integrated fan reduces cooldown time and provides optimal airflow through the optical tube assembly (OTA) while filtering harmful dust from the interior.

The astrograph design is defined by its fast focal ratio, which reduces exposure times without sacrificing image quality and gives you more time for multiple shots of the same object for layering or with different filters. Its internal Ultra-Stable focusing mechanism enables very precise focusing to clearly resolve topographic details on the Moon or split double stars and reveal details of most other celestial objects in between, while minimizing unwanted lateral movement of the primary mirror when focusing or slewing. Since this OTA is designed as an imaging scope, a 42mm camera T-adapter and C-mount imager adapter are included that are compatible with most camera-specific T-rings that are widely available.

Optical Performance

203mm (8") diameter aperture enables near- and deep-sky viewing without being prohibitively large or heavy for easy transport to viewing locations
400mm focal length helps to produce a fast focal ratio
Fast f/2.0 focal ratio requires significantly lower exposure times versus slower ratios to produce the same results
Rowe-Ackermann Schmidt astrograph (RASA) design is purpose built for astrophotography and imaging performance, and is not recommended for visual use
Proprietary StarBright XLT fully multi-coated optical system
Four-element rare-earth glass for true color rendition without aberrations across the entire field of view
Wide 390-800nm spectral range improves images of deep space objects like galaxies and nebulae
Image circle: 22mm (0.86")
Resolution: 0.68 arcsec (Rayleigh), 0.57 arcsec (Dawes)
Back focus: 25mm (0.98") with included camera adapter, 29mm (1.14") from top of threaded collar
Optical window can be removed and replaced with optional filters such as a light pollution filter
Integrated cooling fan brings optical system to ambient air temperature for better performance
Runs on eight user-supplied AA batteries or optional 12VDC power adapter

StarBright XLT Coating System

Multi-layer mirror coatings made from layers of aluminum, SiO2 (silicon dioxide), and TiO2 (titanium dioxide)
Reflectivity is flat across the light spectrum, for both astrophotography/astro-imaging
Multi-layer anti-reflective coatings made from layers of MgF2 (magnesium fluoride) and HfO2 (hafnium dioxide)
High-transmission water white glass corrector lens with 97.4% light transmission

Focuser

Focusing system moves primary mirror forward and back to achieve tack-sharp images
Ultra-stable design minimizes unwanted lateral movement of the primary mirror when focusing or slewing
Fine adjustments for precise focusing, approximately 30 turns of the knob runs through the focus range

Mounting

OTA only, mount and tripod required for proper use
Includes large CGE/Losmandy-D dovetail plate for use on larger more stable mount heads
Weight: 17 pounds

Included Accessories

Standard M42 camera T-adapter accepts most camera-specific T-rings to directly mount DSLR and mirrorless cameras
CCTV/Imager C-thread adapter accepts most camera-specific video T-rings to mount imaging and video cameras
Battery pack takes eight user-supplied AA batteries to power the integrated cooling fan

CGX GoTo EQ Mount with Tripod

Celestron's CGX GoTo EQ Mount with Tripod improves on their venerable CGEM platform to provide users with a heavy-duty research-quality mount for larger optical tube assemblies (OTAs), accessories, and imaging rigs. Engineered to carry a 55-pound payload and outfitted with high-torque motors with a heavy-duty belt-drive system to improve tracking stability and reduce backlash, it is able to smoothly and accurately track near- and deep-sky objects for long periods of time. Its Vixen/Losmandy dual dovetail saddle makes the mount compatible with most plates in use today. To provide a stable platform for the mount and your OTA, a heavy-duty stainless steel tripod is included that sports large 2"-diameter legs, an accessory tray that doubles as a stabilizer, and an adjustment range from 47.25 to 77.5" including the head.

The brain of the CGX EQ is the NexStar+ computer controller. Equipped with a database of 40,000 objects, including the planets, stars, nebulae, galaxies, and the complete Messier catalog, it can also be programmed with up to 100 custom user-defined objects and filters for custom object lists. Its intuitive menu-driven user interface allows you to observe the heavens with nine slew speeds and three tracking rates, plus anti-backlash compensation and Permanent Periodic Error Correction (PPEC) for smoother movements in the motors and improved tracking over time. Features such as guided tours, extended information on 200 popular objects, and multiple alignment options make the NexStar+ controller easy to use and invaluable to new users and experienced stargazers.

Mount

German equatorial mount
55 lb payload capacity
3-65° latitude adjustment range
20° of additional tracking past the meridian provides greater usability
Dual-axis servo motors with optical encoders for smooth tracking and quiet operation
High-torque motors provide smooth tracking and slewing for heavy OTAs
Internal belt-drive system provides smooth, vibration-free tracking while minimizing backlash
Spring-loaded brass worm wheel and stainless steel worm gear reduce friction and improve gear meshing
Limit sensors automatically shut off slewing or tracking before reaching the hard stop fail safe
Internal hard stops for both axes prevent cable tension and tripod strike
Autoguider port for making corrections while astroimaging
Dual Vixen/Losmandy dovetail saddle, compatible with CG-5 and CGE bars
Long clutch levers make tightening and loosening of clutches easier for manual movement
Internal "Real Time Clock" keeps time and site information saved when power is turned off
Internal cables/wires for snag-free operation
Runs on included 12 VDC, 4A car/vehicle power supply

NexStar+ Hand Controller

Features:
Intuitive menu-driven user interface
Nine slew speeds: 2x, 4x, 8x, 16x, 32x, 0.3°/sec, 1.0°/sec, 2°/sec, 4°/sec
Three tracking rates: Sidereal, Lunar, and Solar
Anti-backlash correction: Trains out intrinsic play in gears for smoother movement and tracking
Permanent Periodic Error Correction (PPEC): Improves tracking precision for long-exposure astrophotography and imaging

Database:
40,000-object database
400 user-defined objects for customization
Filters for creating custom object lists
Solar System: All seven planets plus the Moon, Sun, and Pluto
Custom lists of all the brightest stars, double stars, variable stars, and asterisms
Custom lists of all the best galaxies, nebulae, and clusters, as well as the complete Messier catalog and select NGC objects

Functions
Alignment options: One or Two-star, Solar system, Quick, and Last
Sky Tour: Based on location, date, and time, the system shows the best objects in the sky and automatically slews to them
Object info: Provides useful information about the selected object such as magnitude and constellation; includes extended information about 200 popular objects

Physical characteristics:
2-line, 18-character LCD window with red backlighting for comfortable viewing without affecting night-adjusted vision
19 function keys, backlit in red
Mini-USB port: Connect to a computer, for use with software programs for point-and-click slewing capability and updating firmware via PC

Tripod

Stainless steel legs
Adjustable-height 47.25-77.5", including head
Heavy-duty 2" diameter
Wide leg stance provides greater stability, especially on uneven ground
Accessory/eyepiece holder tray that doubles as a leg spreader/lock
Weight: 19.2 pounds

Specifications

8" f/2.0 Rowe-Ackermann Schmidt Astrograph (OTA Only)

Optical Design	Rowe-Ackermann Schmidt
Aperture	8.0" / 203mm
Focal Length	400mm
Focal Ratio	f/2.0
Back Focus	With included camera adapter: 0.98" / 25mm From top of threaded collar: 1.14" / 29mm
Eyepiece Barrel Diameter	N/A
Diagonal	None
Finderscope	None
Tripod	None
Mount Type	Losmandy-D/CGE dovetail plate
Power Requirement	8 x AA batteries 12VDC, 100mA power adapter
Dimensions	Length: 24.7" / 62.8 cm Diameter: 9.3" / 23.5 cm
Weight	17.0 lb / 7.7 kg

CGX GoTo EQ Mount with Tripod

Mount Type	Equatorial
Load Capacity	55.0 lb / 24.9 kg
Motor	Dual-axis servo with heavy-duty belt-drive system
GoTo Capability	Yes, NexStar+ hand controller
Latitude Adjustment Range	3 - 65°
Polar Axis Scope	None
Tripod	Adjustable height of 47.25 - 77.5" / 120 - 197 cm, including head Stainless steel 2"-diameter legs
Power Source	12 VDC, 4 A
Weight	Mount head: 44.0 lb / 20.0 kg Tripod: 19.2 lb / 8.7 kg

Packaging Info
Box Dimensions (LxWxH)	46.5 x 13.8 x 13.0"

In the Box

Bundle Items

8" f/2.0 Rowe-Ackermann Schmidt Astrograph (OTA Only)

42mm Camera T-Adapter

C-Thread Imaging Adapter

Fan Battery Pack

Limited 2-Year Warranty

CGX GoTo EQ Mount with Tripod

NexStar+ Hand Control (EQ)

11 lb Counterweight for Advanced VX

Stainless Steel Tripod

Counterweight Shaft

12 VDC Car/Vehicle Power Adapter

Limited 2-Year Warranty

Celestron 8" RASA Rowe-Ackermann Schmidt Astrograph Telescope with CGX Goto EQ Mount

Price

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