For 30 years, Tele Vue has pushed the boundaries of APO refractors, as well as eyepieces, to the recognized pinnacle of performance. We were gratified but not surprised that Backyard Astronomer's Guide said of the NP101: "optics don't get any better than this." No wonder Sky and Telescope rated the NP101 tops and selected it as the test instrument for its landmark review of the SBIG STL11000 CCD camera . The "is" versions of the Tele Vue-60, 102i, NP101 and NP127 retain the exemplary wide field and planetary visual capability while adding new features to make imaging easier and more flexible.
TeleVue was determined to make the NP series optically, mechanically, and functionally as perfect as possible for imaging up to 50mm diagonal chips without penalty to its near ideal visual operation. How? By applying the developments created for the Tele Vue-60is to the new NP101is and NP127is and then going beyond.
The NP101 (540mm, f/5.4, 4") and NP127 (660mm, f/5.2, 5") maintain their optical specifications yet with redesigned 4-element optical systems. Larger rear lens groups absolutely minimize vignetting in formats up to 50mm diagonal. For these large chips an optional field corrector was developed so the corners of the newly brightened edges would virtually be as perfect as the center of the field.
Next, to take full advantage of the larger lenses, Televue developed a larger focuser and draw tube having a 3" front aperture and 2.4" rear aperture. This eliminates any restriction of the larger diameter converging light cone. They build and test the rack and pinion focuser to hold 12 lbs. of weight, yet still permit extremely fine focusing control via a 10:1 dual speed pinion assembly. This new draw tube also permits quick change from visual to imaging operation and allows full camera rotation without focus change. In addition, it has the capability to correct for any residual focal plane tilt and accepts a "position stop" for our digital micrometer to allow repeatable focus measurement to 0.0001".
To maintain squareness to the optical axis while changing camera orientation, the draw tube has four lock screws that tighten against a taper on the "imaging insert" ring. This insert is threaded to accept Tele Vue's new Imaging System accessories including large diameter extension tubes, optical accessories, and camera and CCD attachments, all with mating threads.
The 10:1 dual speed focuser custom designed by Starlight Instruments provides extremely sensitive focus adjustment, measurable with the optional Digital Micrometer Kit to better than 1/10,000". Also, the optional Focusmate Driver permits electronic motor control of the focusing process. The Focusmate Driver has direction push-buttons and adjustable speed. A tap on the button permits vibration-free focusing in steps as small as approximately 0.0005". The Focusmate Driver can be remotely computer controlled with optional Focusmaster Computer Interface.
Televue NP101is Imaging System Features
- Dual speed knobs are on the right side of the telescope only, the 1:1 left side knob is the classic 5-hole Tele Vue style.
- All knobs have knurled rubber grip rings
- New draw tube also permits quick change from visual to imaging operation and allows full camera rotation without focus change.
- As perfect as possible for imaging up to 50mm diagonal chips without penalty to its near ideal visual operation.
- Larger focuser and draw tube having a 3" front aperture and 2.4" rear aperture.
- Insert threaded to accept Tele Vue's new Imaging System accessories including large diameter extension tubes, optical accessories, and camera and CCD attachments, all with mating threads.
TeleVue Product Number: NPI-4057 All Televue products are available to ship world-wide from OPT, and are covered by a Five Year Worldwide Limited Product Warranty! Always be sure to save your original packaging materials should you need to return any Televue product for warranty or repair.