Takahashi - TOA-150B Refractor Optical Tube Assembly

• 150mm f/7.33 Ortho-Apochromat triplet optics with dual ED elements 
• 4” rack and pinion focuser with camera angle adjuster and 10:1 fine focus
• retractable dew shield
• state-of-the-art optical performance, exceeding even fluorite scopes
• 5-year warranty

The Takahashi TOA-150 refractor provides exceptionally high optical and mechanical quality for the serious visual observer and astrophotographer. The TOA-150 is exceptional for observing and imaging within the solar system. Its images of subtle lunar and planetary details are sharp, with realistic and highly saturated color. They are totally free from chromatic aberration’s violet haze of spurious color, thanks to the scope’s ED triplet optics. The latest antireflection multicoatings and numerous knife-edge internal baffles assure the maximum image contrast possible.

 
The 5.9” aperture of the TOA-150 provides a visual limiting magnitude of 13.4, and a photographic limiting magnitude of well over 15, making it excellent for deep space observing as well. The brighter nebulas and galaxies stand out crisply against a very dark sky background. Binary stars and globular star clusters are particularly well-resolved, thanks to its diffraction-free images, and its freedom from spurious color vividly shows the contrasting colors present in many binary systems.

 
The TOA-150’s f/7.33 focal ratio and 1100mm focal length is long enough, using a 3mm eyepiece to provide 367x, for very high magnification observations of the Moon and planets. It is equally capable of producing a huge 2.27° field at 22x, with a bright 6.8mm exit pupil, using a 2” Takahashi 50mm eyepiece.

This Telescope’s Optical System . . .

• apochromatic triplet ED refractor optics: 5.9” (150mm) aperture, 1100mm focal length, f/7.33 Ortho-Apochromatic triplet lens using two FPL-53 ED (Extra-low Dispersion) glass element flanking a crown glass element for pinpoint stars and images that are free from spurious color (chromatic aberration).
• Multicoated optics: Fully coated on all surfaces with multiple layers of antireflection materials for high light transmission and good contrast.

This Telescope’s Mechanical System . . .

• Retractable dew shield: Slows the formation of dew on the lens to extend your undisturbed observing time. Also improves visual and photographic contrast by shielding the lens from off-axis ambient light (the neighbor’s yard light, moonlight, etc.) For transport, the retractable lens shade keeps the overall length of the optical tube to a manageable 38” when it is retracted and the visual extension tube removed.
• Carry handle: A carry handle at the rear of the tube, just before the focuser, allows easy transport of the optical tube.
• Quick release for optional finderscope: A quick release bracket on the focuser body holds an optional 7x50mm Takahashi finder and mounting bracket, allowing easy removal of the finder for travel and storage.
• Rack and pinion focuser: 4” focuser, with a 2” eyepiece/accessory holder that threads into the focuser drawtube. A 1.25” compression ring eyepiece/star diagonal holder is also supplied. The non-marring soft nylon compression rings of the 2” and 1.25” eyepiece holders won’t scratch the barrels of your accessories or star diagonal, as ordinary thumbscrews can. Dual focusing knobs provide precise image control with either hand. The large focus knobs are easy to operate, even while wearing gloves or mittens in cold weather. There is a 10:1 ratio micro-fine focuser on one knob as standard equipment. This provides ultra-precise focusing for critical high magnification visual use and astrophotography. A large thumbscrew locks the focuser tube in place without image shift at the correct photographic focus.
• Long back focus: Back focus is a very good 225mm, allowing the stacking of a wide variety of CCD cameras, color filter wheels, electric focusers, and film cameras.
• Optional photographic accessories: Three accessories are available to provide a variety of image scales and sky coverage: two focal reducers and an extender.
  The small focal reducer (#TAK130RE) effectively cuts the focal length to 860mm and the focal ratio to f/5.73. The photographic field is now 3.33°, spread over a 50mm image circle for non-vignetted 35mm photography.
  The large focal reducer (#TAK150RE) is designed for medium format photography. It also effectively cuts the focal length to 860mm and the focal ratio to f/5.73. The photographic field is now 6°, spread over a 90mm image circle for medium format (6x7) photography.
  A 1.6x extender (#XTND-T) effectively increases the focal length to 1760mm and the focal ratio to f/11.7. The photographic magnification (compared to a 50mm camera lens) is 35.2x with this extender in use and the field is 1.3°, making it excellent for lunar photography. The extender can also be used visually.
  A variety of photographic coupling attachments and eyepiece projection photography adapters are also available.