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CCA-250 specifications

Optical specifications

Features CCA-250
Optical design Modified Cassegrain
Diameter of the primary mirror 260mm (Useful aperture : 250mm)
Features of the primary mirror 260mm, Pyrex parabolical mirror, F/2.75
Features of the secondary mirror 125mm diameter, Pyrex spherical mirror
Mirror coatings Protected high reflectivity
Obstruction 0.58
Corrector 3 lenses, 80mm diameter
Lens coatings Fully multicoated
Back focus (BFL) 193.9mm (without CAA)
155.4mm (with CAA)
Resolving power 0.47"
Limiting magnitude (visual) 14.1
Clarty 1792x
Standard assembly
Focal length 1247mm
F/D ratio F/5
Image circle 88mm, champ 4° (60% without vignetting)
Resolution 2µ RMS (optical axis)
3µ RMS (10mm)
3µ RMS (20mm)
4µ RMS (30mm)
6µ RMS (40mm)
Takahashi CCA-250 spot-diagram, standard assembly
With 0.73x reducer [TKA82580]
Focal length 910mm
Focal ratio F/3.6
Image circle 38mm
Resolution 4µ RMS (optical axis)
7µ RMS (10mm)
10µ RMS (19mm)
With 1.5x extender [TKA82595]
Focal length 1880mm
Focal ratio F/7.5
Image circle 40mm
Resolution 4µ RMS (optical axis)
6µ RMS (10mm)
20µ RMS (20mm)
With 0.72x 645 reducer
Focal length 890mm
Focal ratio F/3.6
Image circle 60mm
Resolution 4µ RMS (optical axis)
4µ RMS (10mm)
5µ RMS (20mm)
6µ RMS (30mm)
Takahashi CCA-250 spot-diagram, with 645 reducer


Specifications CCA-250
Focuser Motorized, with translation of the secondary mirror
Cooling system 3 fans with 3 temperature sensors
Electric power 12V CC 0.75A
Plugs 1 x Jack plug (power supply)
1 x USB 2.0 plug (focuser and fan control)
Control modes Manual, with pads on the handbox
Computerized, with software supplied (ASCOM compliant)

Mechanical specifications

Features CCA-250
Tube length 870mm
Tube diameter 306mm
Materials Aluminium and carbon fiber
Tube weigth (OTA only) 22.8kg