Takahashi Epsilon 180ED f/2.8 Hyperbolic Flat-Field Astrograph OTA
This first addition to the new Epsilon Series introduces the newly designed ED corrector and fast speed of f/2.8. This fast field photo/visual astrograph is perfect for digital 35mm cameras and CCD cameras. The great speed will enable the imager to record faint nebulosities invisible in slower instruments. Perfect for viewing comets and galaxies.
The Epsilon Series are corrected Hyperbolic Photo/Visual Astrographs providing wide field astrographs and wide field viewing of the object.
The Epsilon 180 is a highly portable, and versatile hyperbolic photo/visual astrograph. Most asrographs provide wide field photographs, but in addition to this the E-180 can deliver wide field views of the objects to be photographed as well. The photographic and visual fields are flat at the f/2.8 speed. This makes the E-180 perfect for photographing comets and groups of galaxies. Finding these objects is made easier with the optional 7x50 finder.
The Epsilon 180 is a doublet using ED glass, perfecting chromatic aberration to less than that of the Schmidt camera.
The Takahashi Epsilon-180ED (D=180mm, F/2.8), based on catadioptric telescope design (means association of lenses and mirrors) offers a fundamental innovation compared with Newton reflector or Schmidt astrograph. Therefore, the Epsilon-180ED suits both visual observation and large field imaging needs.
The Epsilon-180ED wide field is perfectly flat and allows the use of traditional photographic formats as 24x36 (35mm) or 6x6 and even 6x9. Stellar images of less 20µ can be recorded, which highlights the extreme accuracy of this telescope. Epsilon's images provide incomparable contrast and sharpness.
The optical tube assembly (hyperbolical Newton) gives an image very contrasted even with stars located at the edge of the field. Regardless of its photographic qualities, Epsilon-180ED is a first range telescope for large field observation. Observation of stellar fields, star clusters and galaxies will bring you so much pleasure, while the sharpness of star images will reveal the extraordinary possibilities of your astrograph. It proves to be a fabulous instrument for deep sky and comet surveys. The observation of Lagoon and Trifide nebulas in the same field is extraordinarily seizing.
The rack-and-pinion focuser has a rotary system for framing. A microfocuser (MEF-1) is available on option.
The Epsilon-180ED mechanical design quality, perfectly matched with its optics, will make delicate night handling such as collimation (to be trimmed in full day) and the installation of a photographic image or CCD a lot easier, like for instance : focusing, framing of the object, pointing of the guiding star, etc. Few other telescopes on the market make these operations as easy. The comfort of use of Epsilon-180ED allows you a fast control of your telescope adjustments and therefore gives you time to concentrate on the essential : to set your imaging process.
The primary mirror cell is equipped with 3 "double-action" collimation screws (pushing/drawing). Moreover, you have 3 screws with counter-nut to adjust the pressure under the primary mirror in order to minimize the stresses due to strong seasonal temperature changes.
The collimation of Epsilon-180ED is particularly facilitated for various reasons. It is not an high-resolution reflector thus the procedure is less rigorous than on a Cassegrain-like optical design ; collimation on a star will then not be necessary. The optical axis is represented by reference marks on the 2 mirrors. Takahashi conceived a simple system of collimation eyepiece particularly adapted to Epsilon-180ED. Consequently, you will be able to quietly collimate your Epsilon-180ED during daytime, which is a large advantage compared to a traditional reflector. The Epsilon-180ED is a catadoptric reflector, including an hyperbolical primary mirror, an elliptical secondary mirror and a 2-lenses field corrector in the rack-and-pinion focuser. It results a perfectly flat field, ideal for wide field imaging.
- Effective aperture 180mm
- Primary mirror diameter 190mm
- Secondary mirror (minor axis) 80mm
- Focal length 500mm
- Focal ratio F/2.8
- Resolution 0.64"
- Limiting magnitude (visual) 13.0
- Light grasp 661x
- Image circle 44mm (60% not vignetted)
- Back focus (BFL) 56mm (from the end of the corrector.
- Photographic assembly M54mm female on the corrector (for wide T-mount)
Please note this version is a tube only without finder.
|Secondary Mirror Obstruction by Diameter||(minor axis) 80mm|