Takahashi© Cassegrain Reflector 高橋卡塞格林望遠鏡
CN-212 | BRC-250 | BRC-300 | C-300 | C-400

Takahashi© China      


高 橋 中 國



Telescope 望遠鏡 
FS-60C | FS-78 | FS-102 | FS-128 | FS-152 | FSQ-106 | Sky-90  
 TOA-130 | FCT-150 | FCT-200 | FCT-250
μ-180 | μ-210 | μ-250 | μ-300
 CN-212 | BRC-250 | FRC-300 | C-400
MT-130 | MT-160 | MT-200 | MT-250 | MT-300
ε-160 | ε-210 | ε-250 | ε-300 | ε-350
 
Equatorial Mount 赤道儀
TG-SP 2 | Space Boy | P2-Z | EM-2S | EM-10USD3 | EM-200USD3 | NJP | EM-500
EM-10 Temma 2Jr | EM-200 Temma 2Jr | EM-200 Temma2 | NJP Temma2 | EM-500 Temma2 
EM-2500 Temma-PC | EM-3500 Temma-PC 
Accessory 附件 | Price List 價目表

 Brief history of telescopes 望遠鏡簡史

Specification of telescopes at a glance 望遠鏡規格一覽


CN-212 Newtonian/Cassegrain telescope  CN-212 牛頓/卡塞格林望遠鏡

The idea of combining the advantages of Cassegrain and Newtonian configurations in one instrument has been around for a long time but with very few examples commercially available.

Thus it was not so much a novelty of telescope optics , but rather the result of a long held need for the ideal all-round telescope for the amateur use that gave birth to the Takahashi CN-212.

The optical principle of the CN-212 is simple yet clever. From a primary short focus parabolic mirror, pierced centrally, different optical configurations are possible depending on the secondary mirror placed in the light cone. Here we have two telescopes in one, an f/12.4 Cassegrain as the basic configuration, with a hyperbolic secondary mirror for high resolution work, or when you require, by simply replacing the secondary mirror and coupled with a low profile 2" eyepeice adaptor and associated field corrector, you transform your instrument into a brilliant wide field Newtonian with a focal ratio of f/3.9　

Specification of CN-212

Effective Aperture 212mm 212mm
Focal Length 2630mm 820mm
Focal Ratio F12.4 F3.9
Diameter of secondary Ø68mm  
Diameter of diagonal   Ø72mm
Resolution

0.55"

0.55"
Light gathering power

917x

917x
Limiting magnitude

13.4

13.4
Image Circle

36

43
Photographic field

0.8°

2.9°
Finder scope 7x50 6.3° 7x50 6.3°
Length of main tube 855mm 855mm
Weight of main tube 8.5kg (18.7lbs) 8.5kg(18.7lbs)


CN-212 Cassegrain Focus System Chart 

4.  Locking screw
6.  50.8mm adapter
7.  Locking ring
14. Coupling (L)
18. Reducer
19. Reducer (Mewlon)
24. Diagonal Prism (L)
29. 5-turret w/DP (L)
31. TSC Prime focus ring
32. T-mount
33. Wide T-mount
34. 35mm SLR camera
36. TCA-4 camera adapter
45. Couplin, DP (L)
46. Adapter 31.7mm oculars
47. Oculars (31.7mm)
48. Oculars (2")
49. Diagonal prism (M)
60. Vari-Extender
61. Vari-tube
75. CCD camera
80. 50.8mm sleeve (easy guider)
81. Easy guider (Lumicon)
90. Twin View









  


CN-212 Newtonain Focus System Chart  

38.  ø82mm filter
70.  Newtonian visual back (for Lumicon)
71.  Newtonian extension tube (for Lumicon)
72.  Flattener

　
BRC-250  Baker Ritchey-Chretien

The BRC-250 employs non-spherical surfaces for both the primary and secondary mirrors, and when they are combined with two supplementary lenses, eliminates spherical aberration, coma, and even astigmatism with a flat field. It produces a focal ratio of f/5 with a 100mm 5° image circle. It also produces an amazing 2 micron stellar image at the center of the field.

The BRC-250 employs the Baker method to Flatten the field over a wide field. However, because its primary and secondary mirrors are hyperbolic, production was difficult. Today, Takahashi's unique technique in polishing non-spherical surfaces enables the first mass production of Baker Ritchey Chretiens.

The large 100mm diameter image makes the BRC-250 a versatile astrograph. The following formats cam be used: 35mm, 6x7, 6x9, and 4x5. The BRC-250 is temperature compensated by using a space age state-of-the-art carbon fiber tube which assures precise focaus that will not change with temperature fluctuations.

The extremely small stellar images makes the BRC-250 the perfect instrument for CCD imaging. The 100mm diameter image circle will accomodate the largest commercially available CCD cameras　
Optical System Baker Ritchey-Cretien
Aperture Ø250mm Hyperbolic [Enhanced coatings]
Corrector assembly 2 elements [fully multi-coated]
Focal Length 1268mm [effective]
Focal Ratio F/5.0
Light grasp 1276x
Resolution 0.47"
Limit Mag 13.8
Image Circle Ø100mm/ 5°
Stellar images Less then 10 microns at the edge and 2 microns at the center
Tube Diameter Ø280mm [11.02in.]
Tube Length 850mm [with dew shield]
Weight 15.6kg [34.3lbs.]
Finder Scope 7x50 6.3° w/ illuminator
11x70 4.2° optional
Main tube material Carbon fiber
Film formats usable 35mm, 6x7, 6x9, and 4x5


Takahashi C-400 Observatory

The C-400 16" f/14 Classical Cassegrain is part of Takahashi's Observatory Series telescopes designed primarily for research
and educational institutions. This telescope comes standard with a removable f/10.4 focal reducer where a wider field of view is required. Because the C-400 employs the Classical Cassegrainian 
configuration with a parabolic primary mirror and hyperbolic
secondary, extremely high resolution can be obtained without
sacrificing contrast or a flat field.
Secondary obstruction is only 29% with this instrument as compared 
to 40% or greater with typical Ritchey-Chretien Cassegrains. As 
with the FCT-200 and FCT-250 Observatory fluorite refractors, this instrument is designed for rigorous research applications and is constructed with meticulous craftsmanship throughout. The optical
tube assembly weighs 165lbs. so a heavy-duty, permanent equatorial mount with high-precision Go-To slewing such as Takahashi's Temma EM-2500 or EM-3500 (illustrated) is recommended for most 
applications. Since this is a custom made telescope, each
instrument is made to order and delivery times may vary.

Optical System Cassegrain
Aperture 400mm
Effective Focal Length 5600mm
Effective Focal Length (with reducer) 4170mm
Focal Ratio F14
Effective Focal Ratio(with reducer) F10.4
Diameter of secondary Ø115mm
Length of main tube 1620mm
Tube Diameter 430mm
Weight of main tube 75kg (165lbs)

　

　　
FRC-300 by Takahashi© 

 The Takahashi TRC-300 is a new fully-corrected (flat-field, anastigmatic) Ritchey-Chretien Cassegrain specially designed for astro-imaging.

This design will provide pinpoint star images over a 90mm image circle at f/7.8 for CCD or medium format photography.

With the optional dedicated focal reducer, a fully-corrected 36mm image circle can be utilized for CCD-imaging at f/5.9.

TRC-300 comes with built-in temperature compensation device and tube holder.

SPECIFICATIONS for the TRC-300 (Tube assembly only)
Optical System Corrected Ritchey-Chretien
Uses CCD or medium format astrophotography
Aperture Ø300mm
Focal Length 2348mm [effective]
Focal Ratio f/7.8
Image Circle Ø90mm
Focal Length (with reducer) 1770mm
Focal Ratio (with reducer) f/5.9
Image Circle (with reducer) Ø36mm
Tube Diameter Ø324mm [12.76in.]
Tube Length 1030mm [40.55in.]
Finder Scope 7x50 6.3°
Tube Weight 30kgs / 66lbs

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