TeleVue - TV-102iis Imaging System Optical Tube with Ethos 6mm 100° FOV Eyepiece

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 STL-11000 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.

We were 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. 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. The Focusmate 6:1 planetary ball type reduction focuser is supplied standard and 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 push button permits vibration-free focusing in steps as small as approximately 0.0005". The Focusmate Driver can be remotely computer controlled with software under development.

Tele Vue has been known for producing visual instruments "even better than you imagined." We aim to achieve the same with our imaging equipment. Our dedicated local machinists and in-house staff are as committed as ever to deliver on these quality and performance goals.

Features:

• The 102iis uses the larger focuser and new features of the other new Imaging System scopes yet still functions for regular visual and Bino-Vue operation at 1x. With the Imaging System options available, this scope truly can do it all.
• Think 102iis when "back focus" is an issue. Extra back focus permits use of multiple accessories such as filter wheels, off-axis guiders, etc.
• Recommended for use with 35mm or smaller chips.
• New non-restrictive 2.4" focuser with 3" input inside diameter allows maximum performance when using RFL-4087 0.8x reducer/flattener.
• Focusmate installed.
• Sliding captive dew shield
• 2" accessory adapter with clamp ring for 1x Bino Vue use, 5" long extension tube for single use, and photographic accessory adapter are all included.
• Custom fitted hard shell case included. 

Focuser Features...

• 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 with brass clamp ring
• Imaging insert threaded for imaging system components.

Optical Design: Apochromatic Refractor
Aperture: 102mm (4")
Limiting Visual Magnitude: 12.5
Focal Ratio: f/8.6
Focal Length: 880mm
Optical Tube Dimensions: 25.9" (with dew shield retracted)
Focuser Design: 2.4" Focuser with Focusmate