Takahashi CCA-250P O.T.A.


The CCA-250 is Takahashi`s first corrected Cassegrain Astrograph. It was developed as a replacement for the BRC-250 corrected Ritchey.

This instrument was developed to take advantage of the digital age

and provide image circles to cover large format imaging chips. The large 88mm can cover these large chip with a flat field filled with pin point stars.

This astrograph offers versatility. It is a tri-focal instrument that

can be used at its native f/5, at f/3.6 with the small and large 645

reducer or at f/7.5. It will support wide field to narrow field imaging.

The design of this instrument includes a carbon fiber tube and a temperature compensated holder to maintain focus during long exposures.

During long exposures temperatures can change and cause the optics to change focus. The CCA-250 is equipped with three computer controlled cooling fans that are operated by three sensors: one on the primary, a second in the tube and a third in the air to measure ambient temperature to help prevent image shift working in concert with the carbon fiber tube and temperature compensated holder. This cooling system can also be operated manually.

The manual controls and computer interface are conveniently locatedin a control box attached to the rear of the mirror cell.

The control box also includes an input for the supplied 12v power source and a USB input for computer control of the focusing system.

The CCA-250 features a computer controlled secondary ASCOM compliant Active Focus system. The latest version of ASCOM driver (Ver. 1.0.3) can be downloaded from www.takahashijapan.com. This enables computer control by programs such as FocusMax or Maxim DL.

Takahashi`s original secondary focusing system was included with the Mewlon-250 and 300 beginning in 1989, this latest refinement uses a pulse motor which allows for the ASCOM compliant focus programs to operate the Active Focus system.

The CCA-250 employs a corrected cassegrain optical system with a large three element corrector to produce a flat 88mm circle with Stars 6 microns or less out to 50mm and 10 microns or less out to 88mm.


Optical System Corrected Cassegrain

Effective aperture                             250mm

Focal ratio                                            f/5

Metal back distance                         193.5mm

Tube diameter                                    306mm

Tube length                                          870mm [34.25]

Tube weight                                          22.8kg [50.16lbs]

Power source                                       12vDC x 2A




Add to Cart:

  • Model: TCCA250
  • Shipping Weight: 80lbs
  • Manufactured by: Takahashi

This product was added to our catalog on Thursday 08 September, 2011.