
ZenithStar 66mm ED APO
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ZenithStar 66mm ED Triplet APO Refractor
by R.J. Waldman
Guess I'll start this out by saying I have no affiliation with William Optics or any other companies in this review. But you've likely read plenty of reviews, so you know how all that goes...
As an avid camper/hiker/traveler, I'm always on the lookout for a good travel
scope that will go absolutely anywhere. For the past few years this position
has been filled by a 70mm f/5 Orion achromat. Although it was a nice scope,
it was still, well, an f/5 achromat. Whenever a brighter target caught my
attention I had to put up with the bright purple halo. However, when William
Optics released the ZenithStar 66 line of 66mm refractors, I just knew I had
to have one. After careful research and negotiations I convinced the parental
units that the ZenithStar 66 triplet apochromat was the ideal Christmas present.
Then the waiting began..
The shock of ordering a new scope was just beginning to wear off, when suddenly
I heard something that sent a chill down my spine and set my heart pounding...
A diesel engine idling outside my house...
Of course, there can be only one thing that makes this sound...
The FedEx truck
Before you can say APO, I'm in front of the front door waiting for the doorbell
to ring. And it does. And there's the delivery guy, obscured behind an alarmingly
large box.
I'm thinking Does a 66mm scope really need a box that big? Of course,
there's only one proper way to find out. I need to open the box. One look
inside tells me why the box is so large. The scope's shoebox-sized box is
securely held in the outer box by a thick layer of packing peanuts. This makes
a very secure package. It also made a mess in my kitchen. By this time I can
hardly keep my hands steady as I remove the contents of the box.
So what exactly is in the box? The first thing that came out was the carrying
case. It is black with the WO logo in red on the top, and a shoulder strap.
Okay, that was the only thing in the box, but it's really all that
counts. Or more accurately, it's the scope in the case that counts.
And what a scope it was
At first sight, this scope looks like a work of art.The scope is a 66mm ED
(which stands for extra low dispersion", a.k.a "fancy ) apochromatic triplet
with a 460mm of focal length. From the fit and finish to the slick black anodizing,
everything about the outside suggests that what's behind that gold metal
lens cap will be worth every penny. Still, I have to take the scope out and
play with it a bit to be sure.
The scope is covered in slick black anodizing from the tip of the dewshield
to the end of the focuser. It attracts fingerprints like some sort of crazy
oil magnet, but WO threw in a small microfiber-type cloth to clean the tube.
I rack the crayford focuser in and out. It is by far the smoothest focuser
I have ever used. If it were any smoother, I could make it move by thinking
about it. The focuser is a 1.6 focuser, threaded for SCT accessories. A 1
1/4 adapter is included. I release the rotating focuser lock and rotate the
focuser. I expected it to be very sloppy when unlocked. It had hardly any
slop, which, as I found out later was completely eliminated by a five minute
tweak. I slid the retracting dew shield out. It slid out smoothly and stayed
out without slipping.
The scope attaches to a mount via an L-bracket with cork grips and a pair
of 1/4 -20 holes. A quick peek showed the well-coated triplet lens. Mechanically,
this scope is the best I've ever used. And I've used some pretty nice scopes.
By this time I was just itching for first light.
Darkness didn't come fast enough that day. First light was carried out with
a standard Celestron 1.25 mirror diagonal and a light photo tripod, the only
mount and diagonal I had that would work with the scope. The seeing and transparency
were so-so at best.
My first target was Mars. The scope doesn't have a finder, but with only 460mm
of focal length, I could achieve a very wide field of view. I located Mars
with a 40mm Plossl, which gave 11.5x and a view almost four degrees across.
Mars was a small, orange disk. Orange. Not purple. Or red, or blue, or any
other unnatural color I'd associate with an achromat.
My first look through an APO was all I imagined it would be. There was some
spiking visible, but that was entirely from my poor eyes. I bumped the power
up to 92x, revealing a small orange disk with some detail visible. About what
I expected for such a small scope.
My next target was the Pleaides: At 11.5x, the cluster was framed nicely.
Pure blue-white stars, very sharp However, the rotating focuser was bugging
me. It seemed to have loosened since earlier, constantly a bit loose even
when I tightened the lock knob. Though at this point I still didn't know the
truth of the problem. That's still later.
On to a quick star test. I chose to test on Capella. I saw round rings on
both sides of focus. I thought there was a bit of astigmatism, but the fact
that the orientation relative to focuser position changed every time I tried
it confirmed it as a mild case of averted imagination. The seeing was bad
enough that I couldn't see an Airy disk in focus, and out of focus, diffraction
rings were hard to see. But it was still good. What I did manage to see was
good, and no false color.
All too soon the clouds put an end to the session. Which would be my last
until Christmas. This was a Christmas present, after all. Once I'd
made sure everything was okay it was to go right back in the box and under
the tree.
Before everything was packed up, I flipped on the light to diagnose the loose
rotating focuser. It turns out I wasn't even using the rotating focuser In
the dark I had unscrewed the focuser from the tube and I was rotating it at
that point instead Tightening that down removed 90% of the slop. A close look
finally found the source of the remaining 10%- one of the three small setscrews
that hold the rotating focuser on had worked itself loose, and tightening
it a bit made the focuser perfect. No slop, even when unlocked. And as for
the actual focusing action, it was so nice I pretty much forgot I was focusing.
No fiddling, no backlash, no raising the focuser past focus then easing it
back down; I just tweaked the focuser and viewed. Though I did do an unusual
amount of focusing, as the combination of heavy eyepiece, shaking mount, and
overhead viewing made the focuser constantly slide unless I locked it. Some
day I may adjust the tension, but only if the problem gets worse with large
eyepieces.
All too soon it was over. The scope went back into its case, the case went
back into the boxes, and the whole thing went under the tree until Christmas.
It was going to be a lonnnng month...
Fast forward one month. I couldn't wait for Christmas. I just haaad to put the scope to the full moon CA challenge This time the scope rode on
an EQ-3 equatorial mount, which was quite stable under such a small scope.
At 18.4x, the moon was bright against an inky black background. There was
just the tiniest trace of a blue rim. Higher powers showed similar results.
However, when the moon was out of the FOV, a strange round, colorful ghost
image, resembling a rainbow flared into view. Careful examination showed that
this was coming from the anodized front end of the SCT-1.25 adapter. Once
the moon was in view this disappeared.
I took advantage of the fine seeing and give a star test another shot, again
on Capella. The rings were identical on both sides of focus. The scope showed
some miscollimation, but I'm not sure how much of this came from the cheap
Celestron diagonal I was using, and without an extension tube I couldn't check
without a diagonal. I'm sure the oval nature of the miscollimated pattern
is what I mistook for astigmatism on the first test. Even with this miscollimation,
views were good. Castor was easy to split, and all four main stars in the
Trapezium were visible, and the nebula was detailed even with the moonlight.
Just for the sake of experimentation, I stuck on a Celestron 2 SCT diagonal.
As has been mentioned elsewhere, the combination would not focus; the Celestron
diagonal was about half an inch too long. Which, to me, is just another excuse
to get a nice William Optics diagonal.
All minor issues aside, everything about this scope screams quality. Despite
the tiny size, it feels like I got my money's worth.
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