Takahashi CCA-250 optical tube with accessory
The package includes an Electrical Focuser, the OTA with male & female Losmandy dovetail, a 7 x 50 Finder, the Finder bracket, a Finder reticule illuminator, and an additional Female Losmandy dovetail.
The Takahashi CCA-250 astrograph is actually on hold and can not be ordered.
Introduced in 1998, the BRC-250 astrograph adopted a totally original optical design, based on Baker-Ritchey-Chrétien, perfectly designed for the imagery at that time. Following the recent evolution of CCD cameras offering larger sensors, Takahashi decided to modify its optical design. To work out this new CCA-250, successor of the BRC-250, the optician engineer Mr Mori Hitoshi opted for a Cassegrain base to lead to this new instrument perfectly adapted for the various objects of the deep sky.
CCA-250 (CCA stands for Corrected Cassegrain Astrograph) offers 3 kinds of focal lengths by the addition of optional reducers and extenders. From F/5 standard focal ratio at primary focus, it is possible to go to F/3.6 by using one of the 2 reducers or to go to F/7.5 by using one of the 2 extenders available. The choice of the model of reducer and extender will depend on the image circle needed, but also according of the size of the sensor of the camera used.
Finally Takahashi carried out a very multi-purpose astrograph offering a extremely high standard product bringing a great optical quality as well as irreproachable mechanics on top of which is added a splendid design associating aluminum and carbon.
Takahashi has produced a very multi-purpose astrograph offering a extremely high standard product bringing a great optical quality as well as irreproachable mechanics on top of which is added a splendid design associating aluminum and carbon.
The package includes an Electrical Focuser, the OTA with male & female Losmandy dovetail, a 7 x 50 Finder, the Finder bracket, a Finder reticule illuminator, and an additional Female Losmandy dovetail.
Technical Specs
|
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) |
|
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) |
The Takahashi CCA-250 astrograph is actually on hold and can not be ordered.
| Product Status | New |
|---|---|
| Package width | 40 cm |
| Package height | 50 cm |
| Package depth | 100 cm |
| No. of parcels | 1 |