Astronomy Specialist


$3,799.00 AUD
SKU: CE-91073


Rowe-Ackermann Schmidt Astrograph

203.2 mm


400 mm

7.7 kg


The Celestron RASA 8" Rowe-Ackermann Schmidt Astrograph is an incredibly fast f/2 optical system designed for imaging with modern CMOS cameras. The RASA 8" provides a flat field free of optical aberrations across a 22mm field of view, with usable performance up to 32mm making it suitable for APS-C and smaller sized sensors.

Note: the RASA 8" cannot be used with systems requiring filter wheels or large DSLR bodies. Instead, it is recommend to use colour or mono CMOS cameras with a filter drawer. As the focal plane is at the front of the optical system, it cannot be used visually with an eyepiece.



As the RASA 8" is a fast f/2 system, you can use much shorter exposure times than usual to capture faint objects. This combined with the short focal length of 400mm means that you don't need to have super-accurate tracking over extended periods, making the RASA 8" suitable for use on a wide variety of equatorial mounts.

The RASA 8" includes Celestron's Ultra-Stable Focus System which utilizes two sets of precision sealed ball bearings to virtually eliminate lateral movement of the primary mirror when focusing, slewing or tracking.

Building on the legacy of Celestron's Schmidt Cameras of the 1970's, the RASA 8" allows astrophotographers to capture incredible data with minimal exposure times. The 4-element lens group with rare-earth ED glass provide images free from aberrations that are inherent in other types of telescopes.

With an extended spectral range of 390-800nm, the RASA 8" is designed for use with modern cameras that are sensitive to NIR wavelengths in the 700-800nm range. Unlike many telescopes which are only designed for the visual spectrum up to 700nm, this extended range will be well focused in the RASA 8", leading to sharper and brighter images.

The RASA 8" performs best once its optics have reached thermal equilibrium with the ambient air. To aid this, the telescope is equipped with cooling fans which direct air through the tube and around the primary mirror.

Note: it is recommended to only use narrowband filters that are optimized for fast systems such as the Antlia ALP-T FAST or Baader Highspeed CMOS filters.


Optical design Rowe-Ackermann Schmidt Astrograph
Aperture 203 mm (8")
Focal length 400 mm
Focal ratio f/2.0
Resolving power 0.57 arc seconds
Image circle 22 mm, 3.15°
Usable field 32 mm, 4.6° with only minimal performance loss at edge of FOV
Light gathering power 843 times the human eye
Central obstruction diameter 93 mm (46% of aperture diameter)
Wavelength range 390 - 800 nm
Spot size < 4.6μm RMS across image circle
Optical coatings StarBright XLT
Off-axis illumination 93% at 11 mm off-axis
Optical window diameter 46 mm
Backfocus with included M42 adapter 25 mm
Backfocus from top of threaded collar 29 mm
Mount attachment CGE dovetail plate
Focuser Ultra-Stable Focusing System
Included connection adapters M42 x 0.75, C-mount
Tube length 628 mm
Tube weight 7.7 kg
Tube diameter 235 mm
SKU CE-91073



  • RASA 8"
  • CGE dovetail
  • Dew cap
  • M42 camera adapter
  • C-thread adapter
  • Fan battery pack


Due to the very short backfocus of 29mm from the threaded collar, we recommend the Baader UFC filter drawer system for ZWO ASI cameras. or the FCCT filter drawer/tilt adjuster for QHY cameras.

Usage with Baader UFC



In order to connect ZWO ASI cameras with 6.5mm of backfocus such as the 533, 183 and 294 series, you will need the following pieces:

 Usage with Baader FCCT


In order to connect QHY cameras with a 90mm body diameter such as the 268M (pre-June 2023 revision), 294 or 533, you will need the following pieces:

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$3,799.00 AUD

Optical design

Rowe-Ackermann Schmidt Astrograph

Image circle

Focal ratio



203.2 mm

Focal length

400 mm

Optical thickness



Colour or Mono

Pixel size

Sensor dimensions


Sensor diagonal

Quantum efficiency

Read noise

Fullwell capacity

Bit depth


Camera backfocus

Filter size

Filter size

Bandpass (FWHM)

Bandpass (FWHM)

Glass thickness

Mount type

Payload capacity

Latitude range

Dovetail saddle

Slew speed


Periodic error correction

Counterweight shaft

Azimuth adjustment range

Internal diameter

Illuminated diameter

Compatible telescope external diameter


7.7 kg




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