| This Vixen NA140SSf is big aperture fast focal ratio refractor – at a surprisingly not very big price. It’s a full-size 800mm focal length 140mm (5.5") aperture f/5.7 neo-achromatic (modified achromatic) design. This new design uses an air-spaced 4-element objective lens, in two groups, that minimizes residual chromatic aberration. It does it without having to resort to ED glass elements that would be exorbitantly costly in this aperture range. The combination of a crown and flint glass doublet objective in front and a Petzval-like doublet correcting lens at the rear is specifically designed to provide improved color and a flat field that is ideal for astrophotography, as well as excellent visual deep sky observing.
User comments about the scope’s performance are particularly illuminating. Here’s a sample: “Correction is so good, however, that I have also used the telescope for stellar and lunar photography – a use for which I had not originally purchased this telescope." The NA140SS “has excellent imagery across the field of the Canon 20D but seems to have little or no apparent lateral color error. Its low weight for its aperture, easy portability and excellent medium focal length and fast f-ratio make it the perfect 'one telescope does it all’ product."
Measuring 40.3" long, including dew shield, the Vixen NA140SSf weighs a surprisingly reasonable 14.3 lbs., making it a reasonably portable optical tube for use on your own sturdy altazimuth or equatorial mount. The scope is supplied with mounting rings and a dovetail mounting plate that fits all Vixen mounts, the Celestron CG-5 and Advanced Series go-to mounts, and the Meade LXD75 go-to mount. The dovetail can be removed so that the mounting rings can be attached directly to other dovetail plates, such as those used on the Celestron CGE and Losmandy GM8 and G11 mounts. A carrying strap is attached to the mounting rings for easier carrying and assembly in the field.
The NA140SSf has a 2" rack and pinion focuser for use with 2" star diagonals, image erectors, or wide-field eyepieces. A dual T-thread 1.25" flip mirror star diagonal that fits into the focuser’s 2" accessory holder is also standard equipment. This flip mirror lets you switch instantly between two different 1.25" eyepieces to change magnifications (or between a camera using a standard T-ring and an eyepiece) at the turn of a knob. Optional eyepieces are shown in the image to the left, but they do not come with the optical tube. The supplied 7 x 50mm achromatic finderscope has crosshairs and a wide 6.8° field of view that makes it easy to locate targets of interest.
Optically the scope is excellent, with very sharp and detailed high-contrast images. The images are virtually free of spurious color due to its fully multicoated four-element neo-achromatic optics. Mechanically, the scope is very well made and finely finished, as is typical of all Vixen products. If you need a big and optically excellent optical tube to complement your existing quality equatorial mount, at a price that is surprisingly affordable, the Vixen NA140SSf is a scope well worth considering.
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Terestrial Photography
Lunar Photography