CCA-250 - Takahashi Europe

The CCA-250 (Corrected Cassegrain Astrograph) is a flat field telescope dedicated to deep sky astrophotography with an 88mm image circle. It allows the use of 3 different focal lengths by adding optional reducers and extenders. In addition to the standard F/5 focal ratio at the primary focus, it is possible to switch to F/3.6 using either one of the 2 reducers or to F/7.5 using one of the 2 extenders. The choice will depend on the desired image circle and the size of the camera sensor or photo housing used.

Motorised focusing, ASCOM compatible, is done by translating the secondary mirror. The fans responsible for cooling the primary mirror are managed by 3 temperature sensors distributed inside and outside the carbon tube. The telescope is delivered with a 7x50 finder and Losmandy type male and female dovetails.

With the CCA-250 telescope, Takahashi has created an extremely versatile astrograph with a top-of-the-range finish, irreproachable optical and mechanical quality and a magnificent design combining aluminium and carbon.

Specifications

Optical specifications
Optical design	Modified Cassegrain
Combination	Concave parabolic primary mirror + convex spherical secondary mirror + corrector
Diameter	250 mm
At prime focus
Focal length	1250 mm
Focal ratio	F/5
Image circle diameter	88 mm
Metal Back Distance	193.9 mm
With reducer RD CR0.73X
Focal length	910 mm
Focal ratio	F/3.6
Image circle diameter	38 mm
Metal Back Distance	56.2 mm
With reducer 645RD CA0.72X
Focal length	890 mm
Focal ratio	F/3.6
Image circle diameter	60 mm
Metal Back Distance	56.2 mm
With Extender EX CR1.5X
Focal length	1880 mm
Focal ratio	F/7.5
Image circle diameter	40 mm
Metal Back Distance	117.5 mm