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CCD cameras have challenged telescope optics beyond anything ever placed at the focal plane. I knew our APO objectives were up to
the challenge, and with the proper tweaks would be extraordinary tools for the imager. With Tele Vue Imaging System ("is")
telescopes, we have refined our instruments and optional equipment beyond anything a CCD chip has seen. We started small
(literally) in 2005 with the Tele Vue-60is and available Digital Micrometer Kit. Achieving critical acclaim with the 60is, we were
encouraged to further develop "is" telescopes and accessories to maximize aperture, real field coverage and performance, and to
make the processes easier for the imager. - Al Nagler
For 25 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 (May & June 2002) and selected it as the test instrument for its
landmark review of the SBIG STL11000 CCD camera (July 2004). 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.
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.
In order to take full advantage of the larger lenses, a non-vignetting focuser was developed to prevent any restriction of the
larger converging light cone. The draw tube has a 3" front aperture and 2.4" rear aperture. 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.
Focuser Features
A. Large Focuser for NP127is Standard features (A) include:
* Drawtube with 3" entrance aperture, 2.4" exit aperture
* End-ring with tilt capability
* 4-Lock knobs to secure camera equipment or 2" adapter
* Body has brass clamp ring with 2 lock knobs
* Focusmate 6:1 dual speed focuser
* Indexed 2" accessory adapter
* Imaging insert threaded for imaging system components.
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