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.
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The visual performance of the NP101is is identical to that of the discontinuted NP101. Therefore, this excerpt -- from TVNP-101 review by Jeff Kramer on Excelsis.com -- is valid for both scopes.
- This scope is superb. It has a perfect star test and virtually perfect color correction. I cannot see any color on Vega at 300x and I was really looking for it in my tests of this scope.
- As for mechanics, this scope is built like a tank. It is very solid. The focuser is smooth as silk and the satin like finish to the focuser, dewcap, and tube ring are very impressive. This scope is as nice to look at as it is to look through. . The hard case is very strong and it is nice to see that Televue includes such a high quality hard case with this scope when other companies charge several hundred dollars for one. Also, I own the Starbeam Finder and the scope fits in the case with the Starbeam attached as well as the Everbrite Diagonal, Tube Ring, and the DUPS Mounting Plate for my GM8 mount. This was very important to me, as now, I can just pull the scope out of the case, attach it to the mount, insert an eyepiece and I am good to go. When I am done viewing, I have nothing to remove from the scope to put it into it's case. A real time and effort saver.
- Saturn is a spectacular sight with Cassini's Division visible all of the way around the planet as well as a light band and darkening at the top of the planet which is easily visible. I have also seen the A,B, and C Rings. Saturn holds up well at high magnification with this scope and I routinely view it at 270x .
- Jupiter looks very contrasty and detail in the bands is easy to see. In moments of good seeing, 6 to 8 bands can be seen. . I have also seen numerous swirls and irregularities in the North and South Equatorial belts.
- The moon is amazing with this scope with superb contrast and sharp detail. I have never seen any false color on the edge of the moon regardless of the moon's phase.
- I have viewed several double stars with this scope but the one that has impressed me the most is Antares. I obtained one of the cleanest splits I have ever seen with this scope on a night of very good seeing.
- As for deep sky, even though this is only a 4" Scope, it's superb contrast still provides very nice, wide-field views of deep sky objects. I have viewed many of the Messier Objects and the outstanding contrast of this scope shows them with sharp detail. Open Clusters have pinpoint stars and nebula's stand out against a very dark background. Viewing M31, M32, and M110 in the same FOV of a low power eyepiece is a truly awe-inspiring site as is viewing the Pleiades at low power. One other sight that has really impressed me as how often I can see the 6-stars in the Trapezium of M42. This scope does as well as can be expected for a 4" scope.
- Overall, I have been very impressed with my NP101 as it can go from extremely low powers with a wide FOV (13x with a 5 degree FOV using a 41MM Panoptic) to high power lunar and planetary views with superb contrast (up to 216x without a barlow using a 2.5MM Nagler). This scope is easy to set-up and is a pleasure to use. It may be expensive, but I feel it is well worth the price.
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.