 This TeleVue refractor optical tube has:
• 127mm f/5.2 four-element Nagler-Petzval apochromatic optical system
• 2.4" rack and pinion focuser with 2" accessory adapter
• factory-installed Focusmate 6:1 ratio fine focus system
• retractable dew shield
• state-of-the-art visual and imaging capabilities
• 5-year warranty The TeleVue NP127is (Imaging System) refractor sets new optical and mechanical quality standards for the serious observer and celestial imager. TeleVue first reinterpreted the incredible design flexibility of the Petzval portrait lens into an astronomical objective over 20 years ago. They’ve been refining the design ever since. No other optical design affords the same freedom to simultaneously correct for coma, astigmatism, field curvature, secondary spectrum, spherical aberration, and spherochromatism that the Nagler-Petzval design provides. This latest four-element air-spaced Nagler-Petzval system has a 127mm aperture ED doublet at the front of the scope, with a second field-flattening/aberration-correcting ED doublet at the rear. The artful combination of materials and design gives the TeleVue NP127is diffraction-limited performance into the furthest reaches of the visual spectrum. In addition to exceptional visual performance, both inside the solar system and beyond, it has been optimized for deep space imaging, particularly with CCD cameras having large format detector chips with diagonals up to 50mm across. Every optical and mechanical element has been optimized to work as a single integrated unit, with new features to make imaging easier and more flexible. For visual use, the scope’s 660mm focal length is long enough, using a 1.25" TeleVue 2.5mm Nagler eyepiece, to provide 264x for high magnification observations of the Moon, planets, and binary stars; yet it will also produce a huge 3.6° field at 21x, using a 2" TeleVue 31mm Nagler eyepiece for wide field observing. Its quality, easy set-up, and airline portability beckons your use. Manufacturing advances in lens finishing, including interferometric monitoring of all surfaces, and TeleVue’s stringent made-in-the-USA telescope assembly and quality control, insure uniformly excellent results with every telescope, and a level of manufacturer-direct service that’s all too rare. Whether you are interested in terrestrial nature studies, astronomical rich-field or planetary observing, or photography of the earth and skies, just put in an optional star diagonal and eyepiece or attach a camera and the TeleVue NP127is is ready to satisfy your observing desires right out of its case.
This Telescope’s Optical and Mechanical Systems . . . - Nagler-Petzval apochromatic refractor optics: 5" (127mm) aperture, 660mm focal length, f/5.2 apochromatic four-element air-spaced optical system. ED (Extra-low Dispersion) glass elements in both the front and rear doublets of the system provide images that are free from spurious color and other optical aberrations. The newly-redesigned optics feature a field-flattening rear lens group that is larger than that in the previous version of the NP127. This minimizes vignetting in photographic formats having up to a 50mm diagonal. In addition, for CCD cameras using a detector chip with a 35mm or larger diagonal, an optional large field corrector is available so that the stars in the newly brightened non-vignetted corners of the image are virtually as tightly-focused and sharp as those in the center of the field.
- Multicoated optics: Fully coated on all surfaces with multiple layers of antireflection materials for high light transmission and good contrast.
- Dual-speed rack and pinion focuser: The newly-designed focuser has a non-vignetting internally-tapered drawtube with a 3" entrance aperture and a 2.4" exit aperture. This tapered design prevents any restriction of the larger converging light cone from the scope’s larger field-flattening rear lens group. The drawtube terminates in an end ring that has a tilt capability to correct for any residual focal plane tilt. This is particularly important with the more stringent focus requirements of CCD cameras. The end ring also accepts a “position stop" for an optional digital micrometer that allows repeatable focus measurements with a 0.0001" accuracy.
The new focuser’s draw tube also permits quick change from visual observing to astrophotography using separate supplied visual and imaging adapters. It allows full camera rotation without focus change, and without the need to buy a separate camera angle adjuster as some other scopes require. To maintain squareness to the optical axis while changing camera orientation, the draw tube has four lock knobs that tighten against a taper on the supplied imaging adapter and 2" visual accessory holder.
The imaging adapter is threaded to accept TeleVue’s new Imaging System accessories – including large diameter extension tubes, optical accessories, and camera and CCD attachments, all with mating threads. The separate indexed visual adapter has a 2" non-marring brass clamp ring with two lock knobs to hold a 2" star diagonal or other visual accessories firmly in place.
- Fine focus system: The focuser is equipped with a normally-optional Focusmate 6:1 reduction ratio fine focus system on the right focus knob. While the left focus knob still provides TeleVue’s standard focusing speed, the Focusmate on the right knob provides extremely sensitive fine focus adjustment for imaging. Focus changes are measurable with an optional Digital Micrometer Kit to better than 1/10,000" for precisely repeatable focusing. Both the standard focus and the Focusmate use large knurled focus knobs that are easy to operate, even while wearing gloves or mittens in cold weather.
An optional Focusmate Driver permits pushbutton electronic motor control of the focusing process. The Focusmate Driver has directional pushbuttons and adjustable speed. A tap on a pushbutton permits vibration-free focusing in steps as small as approximately 0.0005". The Focusmate Driver can be remotely computer controlled with software under development.
- Optional photographic accessories: Optional photo accessories include the following: a Digital Indicator Kit for digital readout of the focuser position for repeatable focus points; a Focusmate Driver electronic vari-speed motor control for the Focusmate fine focus mechanism; a Large Field Corrector for optimized edge performance with large diagonal CCD chips; extension tubes of various lengths to bring various CCD and 35mm cameras to focus; an adapter to connect the SBIG STL11000 CCD camera; an adapter to connect a standard 35mm camera using a T-Ring; an adapter to connect a Canon EOS or digital SLR using a wide mouth Canon T-Ring; and a 0.8x focal reducer for wider field imaging.
- Sliding captive 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 33" when it is retracted.
- Mounting rings: No mounting rings are supplied for the 127mm diameter optical tube. The optional TeleVue #MRS5 dual 5" mounting ring set is designed specifically for installing the NP127is on wide variety of equatorial mounts and mounting adapters.
- Finderscope mounting point: No finderscope is supplied. However, dovetail accessory mounting slots for a finderscope and other accessories (such as a piggyback camera mount) are provided on the optional TeleVue #MRS5 dual mounting ring set.
- Carrying case: A custom foam-fitted locking hard shell case is standard. The case has a large accessory compartment built into its lid.
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