The Vixen ED100SF Refractor – Superb Optical Quality

October 11th, 2008

The Vixen ED100SF Refractor – Superb Optical Quality

So here we go. There's a knock on the door and a big box arrives. It's either a coffin for a short, skinny person or I've got another telescope on my hands. I wrestled it up on my dining room table, carefully cut the packing tape and revealed the shiny aluminum case that lay beneath the brown cardboard layer with the word Vixen stamped on the outside. Vixen? Haven't we met somewhere before in another life?

For those of you who know me, you know I'm not much of a refractor person, although I own several. The reason isn't because I don't like refractors, it's because I'm primarily a faint galaxy and comet hunter and to get the aperture I need I simply can't afford a refractor that size. However, I am also not adverse to being a sometimes "optical connoisseur" and there have been times in my life that I've been talked into doing things that I probably had no business doing…. and that's how I first got introduced to Vixen refractors. To make a long story short, a friend of mine in California coerced me into purchasing an old 4" Vixen refractor for him from a total (spooky) stranger just because he happened to live in Ohio and I'm the one that ended up footing the bill, packing this anitque across country in a self-made case fashioned from PVC pipe and loving it to death.

And now there's another one here.

Of course, my first experience with a circa 1980 Vixen refractor certainly didn't prepare me for today's modern optics. When I unlatched the clean, neat aluminum case that comes standard with the Vixen – ED100SF I was blown away with the fit and finish of the product itself. Who doesn't love a brand new telescope with a perfect white finish and all the trimmings packed neatly inside custom foam? Everything looks good, right down to the scope rings and Crayford focuser – but the bottom line isn't looks – it's performance. In the long run, I had some serious issues with yesteryear's Vixen refractor and what I want to know is how today's Vixen performs.

One of the first things you need to realize is the Vixen ED100SF isn't a complete telescope. While most of you probably are aware of what an optical tube assembly is, I want to be fair and point out to others that it is only the telescope body with the focuser and mounting rings. In order to keep costs down, optical tube assemblies are offered to those who already have several mounts, tripods and finderscopes – along with a wide variety of eyepieces. This allows folks like me (and many of you) to afford telescopes like the Vixen refractor by making use of things we already have. In this case, the Vixen ED100SF needs to be mounted on something capable of supporting at least 14 pounds, and I happen to have several equatorial mounts capable of filling the bill – along with many different styles of finderscopes and eyepieces to use.

Now that we're set up, are we ready to check out those optics?

As I said, once upon a time I had issues with Vixen optics – very specifically with chromatic aberration. This is also a reason why I am a reflector person. I do not like color fringing. You give me purple and I'll tell you you're giving me poo. Sure. Once upon a time, they tried to correct chromatic aberration by increasing the focal length. This made for great magnification powers and also made for terribly long telescopes. But, purple images or not, I loved that old Vixen… Would the new one behave the same?

The answer is no. Thanks to today's extra low dispersion glass with its little element of flourite, there simply isn't any unwanted color in the image. Now when I look at something, the only purple haze I get is if I'm listening to Jimi Hendrix on the ipod. All of those red, green, and blue wavelengths are coming right together in perfect, crisp focus and the image is absolutely razor sharp. Where once I might have called something a little bit "muzzy", there is only perfection. And it isn't even a stellar image!

The real test of the Vixen ED100SF comes with a perfect airy disk around Vega. Go ahead, do Epsilon! It's perfect and clean. Go ahead and do a more difficult one, like Gamma Andromeda – because you'll see there's three stars there instead of just two. Put your backside down on my observing chair here and watch Jupiter for awhile. Again, even though I am not much of a refractor person or a planetary observer – I could really get to liking views like this! When a galiean moon comes out of eclipse and you can pick out what looks to be a hair-fine line of black between Jupiter's limb and the satellite's limb? What can you say besides "Wow!" The Crayford focuser is as smooth as glass and the optical quality of the telescope remains through every eyepiece I put in it. Wait a week and watch the Moon. No false colors there. Just deep dark craters and perfect definition.

On deep sky performance, I can only be honest. Here, the Vixen ED100SF only performs like a 4" telescope. It doesn't resolve globular clusters or galaxies any better than a similar sized reflector telescope. However, I must be fair and say that I am not an astrophotographer. I can only imagine that the high quality images that I was getting in planetary and double star performance would carry through equally should you wish to image deep sky with this baby. Since the color correction is absolutely outstanding, I can only imagine what would happen if it were combined with the correct filters and timed exposures to pick out HII regions in those distant galaxies I so admire. On open clusters, the Vixen ED100SF also gave precision performance. Objects like NGC 7790 were virtual pinpoints and that's a nice thing to see in any telescope. In side by side comparisons with a Genesis refractor and a Takahashi, I could see no difference in optical performance visually.

At one time the Vixen ED100SF cost in excess of $1200, making it not the type of telescope for everyone. But now, prices have come to $799. Still, not the type of telescope for everyone, but definitely within the range of those interested in superb optical quality. Vixen has definitely come a long way over the years and like that Vixen telescope I delivered to a man in California so long ago…

I don't want to give it back.

The Vixen ED100SF Refractor was kindly provided for this review by Oceanside Photo and Telescope. Our many thanks for the use of this very fine telescope!

Filed under: Telescope Reviews