I am fortunate to live under dark skies. And though the natural beauty of the upper peninsula of Michigan has
nurtured a tourist "Mecca", those skies are preserved by long winters of snowfalls approaching 200 inches
and one of the largest population of flying insects. Thus many visit, yet few choose to reside in the area.
With 15 years of experience and mag-6 skies you might think that my interest would migrate toward mining the
faint smudges noted in obscure catalogues that few amateurs would be familiar with, but you'd be wrong. I love
"doubles" and I'm not ashamed of it. Mind you, I don't ignore the globs, nebulae or distant galaxies
that beckon to every amateur; I do have an observatory at home and a pier mounted C11 that satisfies my occasional
cravings for such treasures, but when I think of new equipment or accessories, my prejudice shows and my mind immediately
zeros in on anything that might enhance my "double star" infatuation.
Thus with so much appearing in print over the past couple of years about Televue Radians, I decided to take
the plunge. I ordered three : the 8mm, 12mm and 18mm. This review will focus in on the 12mm, but the same thoughts
would be relevant to the other two.
To get a good "feel" for the performance of the 12mm, I compared it alongside a couple of other 12mm's
that I own; a 12.5mm Vixen ortho and a 12.5mm Celestron Ultima. Here are the statistics *:
* All statistics taken from the manufacturer's website.
||Celestron 12.5mm Ultima
|# of Elements
The physical appearance of the Radian is quite nice. It's hefty, weighing in at ˝ lb., with a "fit
& finish" that is typical of all Televue products and no doubt behind the user loyalty that these products
have mustered. It comes with a very unique "sliding" body that adjusts the eyecup's height so that when
you position your eye against it, you are taking in the entire field. If you have ever used eyepieces with this
much eye relief and particularly if you don't wear eyeglasses, you can appreciate that it is sometimes difficult
to know just where to position your eye; this eliminates that problem. I had heard mixed reviews about this feature,
but I found myself in the "I like it" group.
As Al Nagler noted on his website, the Radians are aimed toward eyeglass wearers and thus the 20mm eye relief;
however, for a non-eyeglass wearer like me, the 9mm eye relief in both the Ultima and the Ortho was plenty and
a good amount for easy positioning of the eye, so at this focal length the extra 11mm's of eye relief in the Radian
is nice, but not necessary. (I would expect that when you get to focal lengths of "5mm and below", the
20mm of eye relief would make a big difference.)
To run the eyepieces through their paces, I used my Zeiss AS100/1000 refractor. Though an achromat it is virtually
free of secondary color and is very well corrected. Coupled with each eyepiece it yielded about 80X; with each
eyepiece and a 2.4X Vernonscope dakin barlow about 200X.
I waited for a day with relatively high humidity and the resulting light haze that stills the air. From experience,
I've found that this type of day is often followed by a steady night and I was not disappointed.
A quarter moon bathed the night sky in light (the effect enhanced by the haze), but it was cloudless and no
dew problems were noticed. About 80° F.
The moon was hard to ignore and is always a good contrast test, so it became my first target. At 80X all three
eyepieces showed equal contrast and sharpness along the terminator. The Ortho did appear to present a brighter
view, yet it was a very slight difference. I nudged the scope over to include the limb in the view and saw no induced
color in any of the three, even laterally as I allowed the limb to float toward the edge of the view.
With the barlow in place I scanned the region of the crater Clavius at 200X. Try as I might to discover an advantage
in one eyepiece, I found little difference in the views they offered. After switching between the eyepieces for
some time, I could find no evident winner. Each showed Clavius-J clearly; as well as the ridges running north from
the Clavius-C. In fact, each time I thought I had discovered a bit more detail, switching eyepieces brought the
same result in it's competitor; again, no striking difference. Even in off-axis sharpness the Ultima and Ortho
matched very closely the Radian and if there was any difference at all, it was at best - subtle.
There was of course, one area where the Radian struts it's stuff and that was in AFOV. With out a doubt the
60° AFOV of the Radian was a lot of fun on the moon, giving more of that "in orbit" feeling. But
the surprising thing, at least to me, was that Radian gave an amazing sharp-to-the-edge, undistorted view, which
I have found lacking in other "wide field" eyepieces I've looked through. Though the Ortho and the Ultima
also do well in this area, the Radian did it across a 10 to almost 20 degree wider field. I now saw why these eyepieces
had earned their reputation.
Enthused by the finding so far, and despite washed out skies, my second target had to be a double. After all,
the reason I had decided to give these eyepieces a try was the lure of: the sharpness of an Ortho in a "wide-field"
eyepiece. For a "double-star enthusiast this would be "sugar-coated candy".
For a "star-hopper" like me, used to a dark sky with lots of guide posts, a washed-out heavens would
pose a challenge. I opted for an easy double to locate; Epsilon Lyrae. The "double-double", as it is
called, is a popular double for testing optics and I have examined it many times. It would make a nice target for
the 12mm's because both pairs would fit into the same field of view.
I tried each eyepiece with the dakin at 200X. Each component of the "double-double" were split cleanly;
with both pairs sharing the field - a striking view. All three 12mm's gave equal splits, but the radian once again
gave a more pleasing view with the greater AFOV and I also noticed at this point that the sky background in the
Radian seemed slightly darker. The wider view provided by the Radian showed the multiple system more "in context"
with a spattering of background pinpoint diamonds surrounding the twin pairs; wow!
As a double star observer, I have always looked at the Ortho as the eyepiece of choice. Beside a full set of
Vixen's, I own two Zeiss orthos that show outstanding contrast and I still believe that these eyepieces make wonderful
tools for such work. I was pleased to see how well they held up to the more elaborate designs of the modern offerings
such as the Ultimas and Radians. Though in comparison to the Ultimas and particularly now the Radians, they do
give that "tunnel" vision feeling.
Todd Gross once said that his "favorite series of mid-priced eyepieces is the Ultima series" and as
an owner of seven of them, I would have to agree that they are hard to beat for the price. They also matched well,
the sharpness and contrast of the much higher priced Radians. They remain my workhorse eyepieces and I can recommend
The Radians are in my opinion, amazing. They are an engineering wonder, in the fact that such a well contrasted
eyepiece, with a sharp-to-the-edge 60° AFOV, can come in a 1.25" package of reasonable weight. They are
the closest thing to a "wide-field" ortho as you can come; a double-star enthusiast's dream. Though I
will no doubt continue to use my orthos for double star work, the Radians will get lots of use also, particularly
for those picturesque binaries.