Stellarvue SVR105-3 Raptor Astronomical Telescope
By Chuck Hawks and Gordon Landers
The Raptor 105 is Stellarvue's carbon fiber tube version of their SV105 Super APO Triplet. The 4" refractor's objective is an air spaced triplet with an extra low dispersion (ED) optical glass center element. Its design is about as sophisticated as a short focal length astronomical refracting telescope can get. The carbon fiber main tube is lighter (by about a half-pound) than a Stellarvue aluminum tube. Of course, its high-tech appearance is off the charts. SVR105's are individually hand assembled and Stellarvue's Vic Maris personally star tests every one.
Stellarvue's web site describes the Raptor SVR105-3 Super APO in these terms:
" Stellarvue's finest 105mm f-7 air spaced apo triplet made with Ohara Fpl-53 . . . This is one of the best lenses we have ever offered . . . Free of astigmatism and other optical issues . . . Extremely high spherochromatic correction snaps into focus and cuts through the seeing revealing faint planetary details during those moments of steady air. It works equally well for visual and astro-photographic use . . . Perfect star test with zero false color, no astigmatism or coma - this is not a 'compromise' telescope."
We think that makes it clear where the Raptor 105 stands in Stellarvue's line and the world of small refractors in general. Here are the published features and specifications for the SVR105-3 as tested:
The SVR105-3 reviewed here was purchased as a basic telescope, per the description above, without a mount or accessories. For this review, the Raptor 105 was mounted on Stellarvue's excellent MG alt-azimuth mount and aluminum surveyor's tripod with tray (#MG). The MG is an extremely stable mounting system that includes paddle type locks and micrometric slow motion controls. We had a wide variety of high quality 1.25" and 2" oculars available from Stellarvue, TeleVue, Celestron and others. We also had Stellarvue 1.25" and 2" dielectric star diagonals to match.
The first impression of the SVR105-3 is that it is a top-drawer refractor. Both the scope and its associated Stellarvue accessories show a commendable commitment to design and manufacturing excellence. A quick star test verified the scope's perfect collimation.
As soon as the viewing conditions in western Oregon permitted, we took the Raptor 105 to a dark sky site about 18 miles east of Pleasant Hill, located in the foothills of the Cascade Mountains. This site is far enough from the nearest city (Eugene) so that sky glow is not a problem.
For comparison to the SVR105-3, we brought along the Stellarvue SV102ED we had previously reviewed. This is a 4" objective, 735mm focal length ED refractor with a 2009 MSRP of $995. Note that this review is not intended to be a comparison test; the SV102ED was simply there to serve as a known reference. The SV102ED was also mounted on a Stellarvue MG mount/tripod. As alt-azimuth mounts go, the rock solid MG is hard to beat for a 4" refractor.
We were able to view a reasonable number of objects over a period of several hours. The best known of these included the Andromeda Galaxy (M-31), Hercules globular cluster (M-13), Ring Nebula (M-57), Vail Nebula, North American Nebula and the planet Jupiter with its four large moons and surface bands. An oxygen-III filter was used for viewing the Vail and North American planetary nebulas. We successfully split double stars with both scopes, including the component binary pairs of the "Double Double" in Lyra and the beautiful blue/gold pair that comprise Albireo, at the foot of the Northern Cross.
Our Stellarvue refractors were able to show the pale gold and pale blue colors of the two component stars of Albireo. The binary pairs that comprise the Double Double are a sterner resolution test of small telescopes, as these binary pairs are only three and two arc-seconds apart, respectively, but both scopes had no trouble clearly splitting both binary pairs. The seeing conditions allowed us to make good use of oculars as short as 7mm focal length.
Star images in the Raptor 105 were virtually perfect pinpoints of light all across the field of view. With our Mark 1 eyeballs, we could not detect any optical aberrations or color fringing and the background of deep space was velvet black. The view through this scope is GOOD.
Deep sky galaxies and planetary nebula can be difficult objects for any 4" telescope, because of its limited light grasp. However, the Raptor 105 provided good views of all of our deep sky test subjects. Using an O-III filter, the Raptor 105 even provided clear views of the dim North American and Vail Nebulas, an impressive performance, indeed.
It was surprising how many individual stars this Stellarvue refractor could resolve in M13, well into the heart of the cluster at about 70x magnification. The view through the Raptor 105 rivaled what we have seen through good 6" reflectors of nearly twice the focal length.
At no time were we troubled by chromatic aberration (color fringing). Even while viewing the very bright planet Jupiter and the bright limb of the moon, we noticed no lateral color error, a fine performance. We could see up to six cloud bands on Jupiter's surface and the "great pale spot" during the brief periods when the atmosphere was steady. On a bright object like Jupiter, you can benefit from extra magnification and the outstanding optical quality of the Raptor 105 allowed it to make good use of our short focal length oculars.
To summarize the results of our time with the Raptor 105, the Stellarvue SVR105-3 Raptor is an outstanding 4" telescope, the best and most refined that we have ever used. In fact, the most important difference between the Raptor 105 and lesser refractors is its refinement. From its ED glass triplet objective to its carbon fiber optical tube and its 3" Feather Touch dual-speed focuser, this is clearly a scope designed for the carriage trade. Optically, the less expensive Stellarvue SV102ED is so good that it would be hard to justify the Raptor 105's higher price on that basis alone. However, if you want and can afford the best and most refined 4" refractor on the market, take a close look at the Stellarvue SVR105-3. As Vic Maris promised, "This is not a 'compromise' telescope!"
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