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Need back focus? The Tele Vue-102iis has it. Typically, reducer/correctors for doublet or triplet refractors swallow precious
back focus which could otherwise be used for accessories. Since the Tele Vue-102iis is the Imaging System version of the Bino Vue ready 102i, the short tube provides the imager with nearly 5" of back focus with the 0.8x reducer/flattener in place!
Visually, the 102iis functions at its native 880mm, f/8.6 for 1x Bino Vue use. Astrophotography requires the use of the dedicated 0.8x reducer/flattener, yielding a 704mm, f/6.9 system.
The 4" APO-doublet objective makes the 102iis one of the least expensive, multi-purpose, high performance, scopes available in its aperture class.
Mechanically, the Tele Vue-102iis features the large 2.4" focuser. The non-vignetting focuser prevents any restriction of the 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 Tele Vue's 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, in turn, to accept Tele Vue's new Imaging System series of accessories including large diameter extension tubes, optical accessories, and camera and CCD attachments, all with mating threads.
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