Takahashi CCA-250P Tri-Focal Astrograph (Pre-Order for 9/2011)

Manufactured by: Takahashi
Model: CCA-250P


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Takahashi CCA-250P Tri-Focal Astrograph

Designed to replace the Takahashi Baker-Ritchey Chretien BRC-250, the new Takahashi CCA-250P Tri-Focal Astrograph takes its place among the stars as the latest visual and astrophotogic instrument. 

With built-in electric focus, the Takahashi CCA-250P Tri-Focal Astrograph allows use of software to enusre perfect focus... and a large camera rotator can make use of an electric rotator for remote operation. 

Able to operate at three different focal lengths - f/5, f/3.9 (with 6345 Flattener) and f/8 - this new design makes use of today's modern big chip cameras. Add a carbon fiber tube to the equation for light weight, stable temperature operation and excellent focus and you have the new Takahashi CCA-250P Tri-Focal Astrograph! 

With the [Takahashi] Active Focuser system which installs the stepping motor for focus adjustment in rear side of the secondary mirror, the focus adjusting is done by electromotion. Depending upon this system, automatic focusing of the digital equipment became possible. 

By the fact that drive is installed in the tube, the number of cables which become troublesome is decreased. When using automatic focusing function, it connects with the personal computer, and the USB cable from control software Focus of attachment Infinity controls. 

Because you prepare also the driver of ASCOM correspondence, also the control from of FocusMax and MaxIm DL and the like is possible. It operates, the power source of DC12V is necessary. 

Around the principal mirror and inside the tube, temperature of the air is measured with the sensor, when temperature difference of the section is large, in order the ope air temperature to adapt quickly, 3 inhalation fans lead the air to the principal mirror. Be able to set the operation setting of ON and OFF, from Focus Infinity, 3 fans it controls under the conditions which are set. Even with button operation of drive the fan it CAN TURN ON and CAN TURN OFF. The inhalation fan, in order not to become the interference of photographing, has used the vibrating fan low. 

As for the tube, being lightweight, thermal expansion almost has used the domestic carbon tube which is not. Loading to equatorial is not tube band system, is [arigata] [arimizo] formula of the new design. 

With the automatic focusing function of control application “Focus Infinity” of attachment, the focus adjusting of the photographing equipment being automatic with operation from the personal computer, it is possible. Drive and the personal computer are connected with the USB cable, the picture from the camera is captured, optimum focus position is searched. Other than the focus adjusting, it can operate convenient function such as control of the fan and setting of pre-setting position of 3 places with the personal computer of labor assistant. * Only one for Windows.

Takahashi CCA-250P Tri-Focal Astrograph Features...

  • Optical performance: 2 microns RMS-spot radius on axis
  • Image circle: 88mm diameter (60% illuminated)
  • Image angular: 4 degrees diameter
  • Back focus/metal back: 155.4mm -193.9mm with CAA removed
  • Electric focus secondary computer controlled



Mechanical Specs


Diameter of main tube:             306mm

Diameter of dew shield:            321mm

Length of main tube assy:          855mm

Weight of main tube:               Approx: 20kgs

Material of tube:    Carbon fiber 

Electric focus secondary computer controlled     


Optical Specs


Aperture:                         250mm

Central Obstruction:              58%

Focal length:                     1247mm

Focal ratio:                      f/5.0

Optical performance:              2 microns RMS-spot radius on axis

                    :             3 microns RMS-spot radius 10mm off-axis

                    :             3 microns RMS-spot radius 20mm off-axis

                    :             4 microns RMS-spot radius 30mm off-axis

                    :             6 microns RMS-spot radius 40mm off-axis

Image circle:                     88mm diameter (60% illuminated)

Image angular:                    4 degrees diameter

Back focus/metal back   155.4mm

          193.9mm with CAA removed  


Primary Mirror


Diameter:                         260mm

Aperture:                         250mm

Focal ratio:                      f/2.75

Shape:                            Parabola

Material:                         Pyrex

Coating:                          Enhanced multi-layer aluminum


Secondary Mirror


Diameter:                         125mm

Shape:                            Sphere

Material:                         Pyrex

Coating:                          Enhanced multi-layer aluminum


Conversion Lens Group


Diameter:                         80mm

Number of lenses:                 3

Coating:                          Broadband multi-layer anti-reflection coatings


BRC-250P Conversion Lens Group



645 Reducer 0.72X


Focal length:                       898mm

Focal ratio:                        f/3.6

Optical performance:                4 microns RMS-spot Radius On axis

                    :               4 microns RMS-spot Radius 10mm off-axis

                    :               5 microns RMS-spot Radius 20mm off-axis

                    :               6 microns RMS-spot Radius 30mm off-axis

Image circle:                       60mm diameter (60% illuminated)

Image angular:                      3.8 degrees diameter



645 extender 1.6X


Focal length:                       1970mm

Focal ratio:                        f/7.9

Optical performance:                10 microns RMS-spot radius on axis

                     :              10 microns RMS-spot radius 10mm off-axis

                     :              10 microns RMS-spot radius 20mm off-axis

                     :              13 microns RMS-spot radius 30mm off-axis

Image circle:                       60mm diameter (60% illuminated)

Image angular:                      1.7 degrees diameter



Reducer-QE 0.73X


Focal length:                       910mm

Focal ratio:                        f/3.6

Optical performance:                4 microns RMS-spot radius on axis

                     :              7 microns RMS-spot Radius 10mm off-axis

                     :              10 microns RMS-spot Radius 20mm off-axis

Image circle:                       40mm diameter (60% illuminated)

Image angular:                      2.5 degrees diameter


Extender-ED 1.5X


Focal length:                       1885mm

Focal ratio:                        f/7.5

Optical performance:                4 microns RMS-spot radius on axis

                    :               6 microns RMS-spot radius 10mm off-axis

                    :               20 microns RMS-spot radius 20mm off-axis

Image circle:                       40mm diameter (60% illuminated)

Image angle:                        1.2 degrees diameter

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