Celestron RASA 11 V2 Astrograph – 11" f/2.2 (CGE Dovetail)

DESCRIPTION

The RASA 11 V2 (Rowe-Ackermann Schmidt Astrograph) by Celestron is an ultra-fast f/2.2 imaging telescope, purpose-built for deep-sky astrophotography. With a generous 279 mm aperture and a short 620 mm focal length, it offers a large, flat imaging field optimized for sensors up to 52 mm diagonal.

Its 4-element rare-earth glass corrector delivers stunningly sharp stars free of coma, field curvature, and chromatic aberration. The telescope maintains pinpoint stars across the entire image circle, with less than 4.4 μm RMS spot size, ensuring exceptional image quality even at the edges of large-format sensors.

At the heart of the system is the Ultra-Stable Focus System (USFS), which uses a precision linear bearing to prevent focus shift and mirror flop. Combined with a 12V MagLev cooling fan and dust-protected vents, the system maintains thermal equilibrium and stable performance throughout imaging sessions.

The optical tube is made from lightweight yet rigid aluminum. Dual CGE dovetail bars are integrated for compatibility with heavy-duty equatorial mounts and additional accessories.

The RASA 11 V2 is strictly for imaging and does not support visual use. The camera is mounted directly at the front of the optical train at prime focus. T-thread (M42) and M48 adapters are included, and the standard backfocus is 55 mm from the adapter or 72.8 mm from the collar.

This astrograph is ideal for creating mosaics, capturing faint wide-field targets, or comet hunting—particularly with CMOS or full-frame CCD cameras.

TECHNICAL SPECIFICATIONS

Optical Design: Rowe-Ackermann Schmidt Astrograph
Aperture: 279 mm (11")
Focal Length: 620 mm
Focal Ratio: f/2.2
Image Circle (optimized): 43.3 mm
Useable Field: 52 mm
Resolution (Rayleigh/Dawes): 0.49"/0.41"
Wavelength Range: 400–700 nm
Spot Size: < 4.4 μm RMS
Central Obstruction: 114 mm (41%)
Off-Axis Illumination: 83% at 21 mm
Optical Coatings: StarBright XLT
Optical Window Diameter: 68 mm
Focuser: Ultra-Stable Focus System (USFS)
Backfocus (with adapter): 55 mm
Backfocus from collar: 72.8 mm
Tube Length: 838 mm
Tube Diameter: 330 mm
Telescope Weight: 19.5 kg (43 lbs)
Cooling: 12V MagLev fan with dust filter
Mounting: Dual CGE dovetail bars
Included Accessories: 42 mm and 48 mm camera adapters, dust cover, fan battery pack
Max Load at 5" from corrector: 33 lbs (15 kg)