Astronomy Specialist

TAKAHASHI CCA-250 ASTROGRAPH

SKU: TK-TCK25000

Takahashi

Corrected Cassegrain astrograph

250 mm

f/5

1250 mm

22.8 kg


 

Contact us for availability!

 

The Takahashi CCA-250 is a Corrected-Cassegrain Astrograph designed for extreme deep sky imaging. The flat-field optical design combines a concave parabolic primary mirror and convex spherical secondary mirror, with an integrated corrector to provide a huge 88mm image circle, making it suitable for use with medium format sensors.

The CCA-250 has a native focal length of 1250mm and a fast focal ratio of f/5, making it the ideal instrument for galaxies and planetary nebulae. The motorized secondary mirror allows precise focusing with either the included hand controller or over ASCOM. Additionally, the tube features three cooling fans for the primary mirror with temperature sensors both inside and outside the carbon fibre tube.

In addition to the standard f/5 configuration, a 0.73x focal reducer is available (sold separately), reducing the focal length to 910mm and focal ratio to f/3.8 for wider views and faster exposure times. For large sensors, the 645 0.72x Super Reducer is available, reducing the focal length to 890mm  and focal ratio to f/3.6 and providing an image circle of 60mm. A 1.5x focal extender is also available.

 

 

Spot diagram of Takahashi CCA-250 at prime focus.

 

 

Spot diagram of Takahashi CCA-250 with RD CR  0.73x focal reducer.

 

 

Spot diagram of Takahashi CCA-250 with 645 Super Reducer CA 0.72x focal reducer.

 

 

Spot diagram of Takahashi CCA-250 with EX CR 1.5x focal extender.

 

 

Optical design Modified Cassegrain
Mirror configuration
Concave parabolic primary + convex spherical secondary + field corrector
Focuser
Motorized secondary mirror focuser
Primary mirror diameter
250 mm
Focal length at prime focus
1250 mm
Focal ratio at prime focus
F/5
Backfocus distance at prime focus
193.9 mm
Tube diameter 306 mm
Tube length 870 mm
Tube weight 22.8 kg
SKU TCK25000

 

Prime focus focal length 1250 mm
Prime focus focal ratio
F/5
Prime focus backfocus distance
193.9 mm
Prime focus image circle 88 mm
RD CR 0.73x reducer focal length
910 mm
RD CR 0.73x reducer focal ratio
F/3.6
RD CR 0.73x reducer backfocus distance
56.2 mm
RD CR 0.73x reducer image circle
38 mm
EX CR 1.5x extender focal length 1880 mm
EX CR 1.5x extender focal ratio F/7.5
EX CR 1.5x extender backfocus distance 117.5 mm
EX CR 1.5x extender image circle 40 mm
645 CA reducer focal length 890 mm
645 CA reducer focal ratio F/3.6
645 CA reducer backfocus distance 56.2 mm
645 CA reducer image circle 60 mm

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TAKAHASHI CCA-250 ASTROGRAPH.

TAKAHASHI CCA-250 ASTROGRAPH

$1.00 USD

Optical design

Corrected Cassegrain astrograph

Image circle

Focal ratio

f/5

Aperture

250 mm

Focal length

1250 mm

Optical thickness

Threads

Cooled

Colour or Mono

Pixel size

Sensor dimensions

Resolution

Sensor diagonal

Quantum efficiency

Read noise

Fullwell capacity

Bit depth

FPS

Camera backfocus

Filter size

Filter size

Bandpass (FWHM)

Bandpass (FWHM)

Glass thickness

Mount type

Payload capacity

Latitude range

Dovetail saddle

Slew speed

Encoders

Periodic error correction

Counterweight shaft

Azimuth adjustment range

Internal diameter

Illuminated diameter

Compatible telescope external diameter

Weight

22.8 kg

Length

Width

Height

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