Celestron Telescope Astrograph S 203/400 RASA 800 OTA (60246)

This advanced astrograph is designed to make capturing breathtaking astrophotos effortless when paired with a modern DSLR or astronomical CCD camera. Its innovative optical design features a four-lens corrector made with rare earth glass, effectively minimizing chromatic aberration, coma, and field curvature. This level of optical quality and precision is unparalleled in its price range, delivering exceptional spot size across the entire image field while keeping vignetting to a minimum.

Key Features:

• Super-Fast Optics: The 11" f/2.2 optics provide sharp imaging for APS-format sensors and are optimized for sensor sizes up to a 70mm field diagonal.

• Extremely Short Exposure Times: The RASA Astrograph captures images 20 times faster than an f/10 system. A 30-second exposure at f/2.2 is equivalent to a 10-minute exposure at f/10, making tracking control unnecessary.

• Wide Field of View: With a 620mm focal length, wide-angle shots are effortless, allowing you to capture expansive views of the night sky.

• Precision Focusing Mechanism: Bronze bearings reduce image shift, while the 10:1 FeatherTouch micro-focuser ensures precise focusing.

• Innovative Features: A quieter 12V MagLev fan minimizes cooling time, prevents dust contamination, and optimizes air circulation in the optical tube assembly (OTA). Adapters for various popular camera brands are included. Back focus distances: 55mm for supplied adapters and 69.26mm for the front lens group.

The term RASA stands for Rowe-Ackermann-Schmidt Astrograph, named after Dave Rowe and Mark Ackermann—renowned optical designers with numerous patents to their names. This astrograph is a culmination of their expertise and innovation.

Important Note: The RASA 800 is not compatible with standard DSLR cameras due to its short back focus. It is best used with mirrorless cameras or compact CCD/CMOS astronomical cameras.

Specifications

Optics:

• Type: Reflector

• Build: Astrograph

• Aperture: 203mm

• Focal Length: 400mm

• Aperture Ratio: f/2

• Resolving Capacity: 0.68 arcseconds

• Light Gathering Capacity: 843x (compared to the human eye)

• Tube Length: 628mm

• Coating: Starbright XLT

• Tube Material: Aluminum

• Tube Weight: 7.9kg

• Limiting Magnitude: 13.3 mag

• Tube Diameter: 235mm

• Tube Construction: Full tube

Reflector Details:

• Secondary Mirror Obstruction: 46%

• Secondary Mirror Diameter: 93mm

• Central Mirror Ventilation: Yes

Focuser:

• Back Focus: 29mm & 25mm (depending on configuration)

• Gear Reduction: 1:10 fine focusing mechanism

• Build Type: Linear Crayford

Mount:

• Mounting Type: No mount included (OTA only)

Included Accessories:

• Prism Rail: Losmandy-style rail included

• Camera Adapter: Supports M42 and C-Mount connections

• Battery Compartment: Yes (for fan operation)

• Carrying Handle: Yes

General Information:

• Series: RASA

Applications:

• Moon & Planets: No

• Nebulae & Galaxies: Yes

• Nature Observation: No

• Astrophotography: Yes (primary use)

• Sun Observation: No

Recommended For:

• Beginners: No

• Advanced Users: Yes

• Observatories: Yes

Miscellaneous Details:

• Battery Type Required for Fan Operation: Mignon (AA, LR6)