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Astronomy Review Excerpts from "A wide-field imager's dream scope"
- Appearance, fit, and finish
- Tele Vue has a reputation for producing telescopes as beautiful to look at as they are to look through, and the NP101is is no exception. From the optical tube's pebblegrain, powder-coated ivory finish to the glass-bead-finished, black-anodized focuser, lens cell, and dew shield, the telescope exudes quality.
- Illumination and color
- The NP101is provided a well-illuminated, uniform field that dropped off by less than 10 percent at the extreme corners.
Because the typical CCD chip detects a wider range of wavelengths than the human eye, deficiencies in color correction are obvious. The usual symptom is blue-bloat, where blue halos surround stars. The NP101is was free of chromatic aberration, as demonstrated by the celestial images accompanying this article.
- Visual observing
- This telescope offers a side benefit for nonimagers: It's an even-better observing telescope. A large-chip CCD camera with small pixels requires telescope edge-field performance that far exceeds the performance required for visual observation.
The NP101is provided a visual observing experience unmatched by most similarsized telescopes I have used.
The visual performance of the NP101is is identical to that of the discontinuted NP101. Therefore, this excerpt — Premium Refractors: Having It All by Alan Dyer, from May 2002 issue of Sky & Telescope — is valid for both scopes.
Great optics are easy to evaluate — the NP 101 showed no sign of any aberrations, period. End of review! But to elaborate — under a star test at high power I saw no color, no astigmatism, no spherical aberration, not even any asymmetry in extrafocal patterns from sphero-chromatism. Bright stars appeared as clean, white disks right through focus, with no magenta or cyan fringing inside or outside of focus. In focus, stars appeared as tight, sharp Airy disks, surrounded by a subtle inner diffraction ring and no spurious fuzz — a textbook-perfect pattern.— Dyer, A. "Premium Refractors: Having It All". Sky & Telescope (May 2002). Read More.
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