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The Stellarvue SV66 Sixty Second Super Scope

Posted by david elosser   11/30/2006 12:00AM

The Stellarvue SV66 Sixty Second Super Scope
Okay, I can see the collective eyebrow raising out there for referring to a 2.6” refractor as a “super scope.” But you have to admit the title has alliteration. When I choose this scope I was looking for a small, high quality lightweight telescope that could fulfill a wide range of responsibilities. I wanted to use this telescope for solar, spotting, birding, and astronomical work. And, I needed something that sets up quickly, within a minute or two out of the carrying case. After all, wildlife often does not hang around for very long. My new scope did not have to be the best in anything, but I was looking for the highest possible performance in a small package. Would I find this in the Stellarvue SV66? Actually, I got more than I bargained for.

Birds of a feather.
I am familiar with this class of small refractor, as I own a Televue Ranger, which has a high quality 70mm ED doublet. I wanted to purchase the SV66 as an upgrade to the Ranger. The SV66 is very similar in appearance to other brands of 66mm telescopes, and for good reason. For the most part, it sports the same outerwear: optical tube, two-speed 1-1/4” Crayford focuser, and sliding dew shield are all common to other brands. It has a 2” dovetail bar threaded for tripod photo heads, or the bar will fit into several brands of altaz mounts with a 2” jaw like the Stellarvue M1. The bar can be removed if you decide to use mounting rings or use it as a guide scope. There are no focus issues with this telescope as it comes out of the box. All of my extensive collection of eyepieces comes to focus not only with the Stellarvue 1-1/4” diagonals, but aftermarket diagonals as well. The focuser was the first reason for my wanting to purchase the SV66. The Ranger has a helical focuser that is fine for astronomical use. But I found it to be cumbersome while trying to track moving targets during the day. I like the Chinese built Crayford focuser of the SV66. The coarse focus of the Crayford means I can easily follow birds as they move about the sky or terrain. The fine focus allows me to zero in on high power views of the Moon, planets, or multiple stars. The second reason is the optics. The SV66 has better color correction than the Ranger, which is an achromat. This superior color correction ended up making the SV66 even more versatile that I originally planned, which I will go into later.

Okay so what’s the difference?
When you shop around the 66mm telescope brands, you will notice that the Stellarvue SV66 is a bit more expensive than the rest. The reason is the ED doublet objective. It is mounted in a unique Stellarvue lens cell with six contact points that allow the technician to achieve perfect alignment of the telescope. According to Vic Maris of Stellarvue, it takes approximately one tedious hour to accomplish this. Alignment is always maintained even if the scope is jarred. The telescope is both bench tested and star tested before leaving the Auburn California plant and shipped to the customer. This, of course, makes the SV66 more expensive, but is it worth it? For many, yes, but to others, no. There is, however, a guaranteed performance of the SV66 that the new owner can feel confident with. The user knows it will be in perfect alignment and free of coma and astigmatism.

Putting it together.
I purchased a Kendrick Baader solar filter and cut the foam out from between the two 11/4” eyepiece cutouts in the case that comes with the telescope. This left a convenient spot to store my Kendrick/Baader solar filter. My 8-24 zoom eyepiece fits nicely in the 2” eyepiece cutout. I purchased the Stellarvue 1-1/4” dielectric diagonal and deluxe 45 degree prism diagonal with the telescope, and these two fit nicely into the compartment in the lower right corner. I now have a complete, very portable system that’s ready for action. I carry my Bogen 3001 tripod and photo head separately. Additional accessories like a 2x Barlow or filters can be carried in a fanny pack if desired.

Walking on the Sun.
My first light with the SV66 was sunlight. Even though this telescope has a small aperture, all of the features visible in a white light filter could basically be seen: sunspots (with umbra and penumbra), faculae, and grain. All of this depends on atmospheric conditions, of course. But with steady skies on October 2nd, I was able to zoom in on sunspot 913. At 100x I could see that one of the umbrae had just split into two, with a hairline crack between them. The smaller group, 914, showed a small spot that was beginning to split into two. Grain and faculae was very easily seen a low powers. Although the detail is good, I noticed very quickly that I could not see the fine feathering of the edges of the umbrae like I can in my 102mm doublet apochromat.

Taking flight.
One Sunday morning, I installed the Baader filter for a quick look at the sun: no spots were there, and the air was too unsteady anyway. That's okay because a minute later I was watching a Blue Jay on top of my neighbor's tree. The Vixen 8-24 zoom worked very well. I got an excellent look at the 12mm setting (33x) and the depth of field, at least
with this eyepiece, was very flat. I did not have to refocus when the wind blew my friend perched on a limb around in the field of view. He was up there for 5-10 minutes with an acorn in his mouth. Because he was facing me, I got a rare opportunity to see what he looked like from the underside. He had a pretty scaling pattern to the tail feathers, and I could easily see detail in the fine downy feathers of his belly.

Family Photos.
The Stellarvue SV66 focuses down to about 15 feet (without the use of an extension tube), which makes this an excellent “garden” telescope. From 15 feet, I got a clear and detailed view of my Cosmos flower garden. Lining the telescope up with one of the 4” blooms, I quickly noticed that the apparent depth of field was generous enough to give me a clear and sharp image from petal to petal. After observing for a few minutes at 26x, a green inch worm began walking across the cosmos bloom, although I must say that he looked more like a “foot worm” through the eyepiece.

On a whim I decided to attach my Canon Rebel camera body with a Meade universal adapter and load it with Fuji 100 film. I never had much luck with using the Ranger for daytime photography; it just has too much chromatic aberration that degraded my landscapes. The SV66, on the other hand, has very well corrected ED optics and, as you can see from the photos of our dog Audrey below, has very accurate color as well as remarkable sharpness. The magenta color cast that suffered my photos with the Ranger all but disappeared with the SV66. In the cropped close-up, noticed the lack of spurious color in Audrey’s chain link collar. A backlit cosmos bloom also makes a wonderful subject for photographing.

The excellent photographic performance of the SV66 surprised me: the SV66 is, after all, first and foremost a telescope. So I wouldn’t recommend rushing out and buying one of these as a 400mm telephoto fixed-aperture photographic lens. Or would I?

Night rider.
The SV66 is equally impressive under a starry night. On the Moon and Saturn, it is easily taken up to 125x or more with tack sharp views. When transparency and seeing are excellent, Saturn displays its rings with the Cassini Division discernable as well as the shadow of the rings as it crosses the planet. The prominent band in the southern hemisphere is also evident. Unfortunately, at 2.6 inches of aperture, you won’t catch many moons; two or three at best. The view of the lunar limb is absolutely tack sharp. The “bird’s eye” views of the mountains are easy to pick out even with powers well under 100x. Contrast is excellent for this size scope and I once could even see the craterlets in Plato, (well at least their tiny halos) as well as the fan-shaped albedo feature spreading across the crater floor. At 125x the crater Hadley and the Catina Muller craterlet chain were resolved without difficulty; each of these impacts is only about 4-5 km wide.

Clothes make the man.
And eyepieces make the telescope. With my 25mm Erfle installed for 16x I can get a great view of the entire Sword of Orion with plenty of room to spare, but the Trapezium is not resolved. With my 28mm Pentax, not only do I get more nebular detail in spite of the lower 14.3x power, but I can also resolve the Trapezium into its tiny pinpoint stars. Another example: with my 8-24 zoom set at 50x I could not see Rigel’s tiny companion. With a 2.5x Televue Powermate added in, I set the zoom at 42x and saw Rigel’s companion star. In short, if you are not seeing what you think you should with this telescope, take a good look at your eyepiece collection.

A long reach with short arms.
Now this telescope does not have a lot of light grasp, but there are still plenty of photons making their way through to tickle your retina. The view of deep space objects within reach of this telescope may be dim, but that does not mean they are necessarily “inferior.” A good example is M11, the Wild Duck Cluster in Scutum. Through my 8” Dobsonian, I see a beautiful splash of stars swirling around in a sea of black velvet. With the SV66, the appearance is quite different. I can see a bright star surrounded by an irregular hazy glow. To me, it’s not better or worse than the Dob’s view, just different. Globular clusters like M15 in Pegasus or M80 in Scorpius may or may not be resolved into individual stars, but seeing these lovely objects in context with the surrounding star field can be equally rewarding. Certainly large open clusters like the Hyades or Delle Caustiche seem to be made for small scopes like these.

Dude, have you seen my filters?
I have a wide variety of filters in all of my eyepiece cases, which is why I can never seem to find the one I want when I want it. With M27, the Dumbbell Nebula in view, I wanted to see what kind of filters could successfully be used with a scope this small. My Orion Skyglow filter went AWOL. My IDAS V3 Nebular filter is similar, and gave a very nice view of the planetary nebula. Image brightness went down a bit, but the increased contrast really made the nebula stand out well against the background of sky and stars. An O-III filter isolated the nebula even more, but I really could not see any more detail and the overall view was quite a bit darker. On the Ring Nebula M57, the IDAS worked fine, but the O-III filter was a definite overkill, in my opinion. If you want to use narrow or broad band filters, my advice is to keep the power low, as scopes of this size loose light rapidly with increased magnification.

And now for the recap.
In summary, here is my assessment of the performance of the SV66, using my 102mm doublet apochromat as the “excellent” standard:

Solar: good (white light filters produce a rewarding image, but lacks the depth and detail of a larger scope)

Terrestrial, birding, spotting: excellent- (actually I would rate it higher than a 4” scope because of the portability, but the SV66 is not weatherproofed.)

Lunar/planetary: good (excellent color correction, detail and sharpness, with resolution limited only by the aperture size)

Splitting double/multiple stars: excellent- (up to the Dawes limit, with tight, sharp airy discs and wonderful variety of star color)

Deep space objects: good- (not a galaxy killer, but scores of DSO’s can be seen throughout the course of the year depending on your local conditions)

Ease of setup, transportation: excellent+ (scope, tripod, and mount can be carried around with one hand!)

Use as a camera lens: good+ (fixed aperture, bulk, and 3-1/2 pound weight limit the versatility, but the photographic image is excellent, rivaling the image of some of my SLR lenses)

Back in the case.
The Stellarvue SV66 has definitely fulfilled my requirements for a small portable scope with excellent optics, at a price that won’t (totally) break the wallet. (Telescopes have come a long way since I purchased my Televue Ranger, which when purchased new was twice the price of the SV66.) It takes only a minute or two to carry it out to my yard and set it up for a wide variety of tasks, day or night. Its performance as a daytime camera lens was a pleasant surprise. If the view through the eyepiece captivates you, just put on an SLR body and capture that Kodak moment. My SV66 “super scope” is sure to give me many hours of enjoyment for years to come.

David Elosser
Kernersville NC

Click here for more about this subject. -Ed.