Takahashi - CN-212 8.35" Cassegrain / Newtonian on EM-200 Temma II
Mount
- The CN-212 is two, two, two telescopes in one!.
- Choose either a f/12.2 Cassegrain or f/3.9 Newtonian configuration.
- This model comes with the EM-200 Temma II Mount & SE-M tripod, as welll as several other accessories.
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 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.
CN-212 8.35" Cassegrain/Newtonian on EM-200 Temma II Mount Specifications
- Type: Cassegrain or Newtonian
- Effective aperture: 8.3" (212mm) in Cassegrain config, 8.3" (212mm) in Newtonian
config
- Focal length: 104.3" (2650mm) in Cassegrain config, 32.3" (820mm) in Newtonian config
- Focal ratio: f/12.4 in Cassegrain config, f/3.9 in Newtonian config
- Diameter of secondary: 2.7" (68mm)
- Diameter of diagonal: 2.8" (72mm)
- Resolution: 0.55"
- Light gathering power: 917x
- Limiting magnitude: 13.4
- Image Circle: 36" (914mm) Cassegrain config, 43" (1092mm) Newtonian config
- Photographic field: 0.8 degree in Cassegrain config, 2.9 degree in Newtonian config
- Finder scope: 7x50 6.3 degree
- Length of main tube: 33.7" (855mm)
- Weight of main tube: 18.7 lbs. (8.5kg)
EM-200 Temma II Mount
The EM-200 Temma II is an accurate, precision-built GoTo German equatorial mount that
provides a stable platform for payloads of up to 40 pounds. It is an ideal mount for any type telescope, be it a refractor,
reflector, or cassegrain.
The modern aesthetic design of the EM-200 is highly attractive as well as beautifully functional. The RA and
DEC stepper motors are fully integrated into the mounting,and the high precision design and construction provides cyclic errors
lower than +/- 5 arc seconds.
The integrated polar alignment telescope has an illuminated reticule which can be dimmed to suit the user or
observing conditions. In conjunction with the precision altitude and azimuth adjusters, this will typically give polar alignment
accuracy within 2 minutes of arc of the celestial pole.
The new style EM-200 mounts include the ability for operation on 12v or 24v and feature high speed slewing
at 350x [sidereal rate] at 12v and 700x at 24v. 12V operation takes place with the use of the hand controller only. The mount will
then function just like the EM-200 USD model (no GoTo functions). However, with the use of the hand controller and your PC, you
can operate with 12V or 24V (two 12V batteries connected in series). 12V will give you a slewing speed of up to 350X sidereal, and
24V will produce slew speeds of up to 700X. A standard hand controller and power cable for 12V/220V battery connection is
included.
