Sky and Telescope
$100.00 - 125.00 each
of eyepieces that contain the rare earth element Lanthanum and
featuring 20mm eye relief.
eyepieces in a mid priced bracket.
I have been observing since I was 6,
and now that I am 29 I have acquired the financial
autonomy to buy an eyepiece now and then. I would not rate myself as an
expert observer as I have been in and out of the hobby, and as most
amateurs, especially those who are married, have children and live in
urban areas, have too little quality observing time. I have two places to
observe: my garden in Northern France with 120 clear nights a year and mag
3.5 skies, where I just give a little glimpse when it's clear at the moon
and planets (the Orion nebula is "seeable" but a sure
disappointment) , and a place in rural, southern France with darker and
clearer skies. There I hunt galaxies and globulars which are my favorite
targets, but I only have a handful of good nights there per year. My
e-mail is email@example.com
I purchased all these eyepieces separately, mostly on reputation and
because I wanted high-power, long eye-relief eyepieces after years of
straining with 7- to 9-mm focal length Orthos and Plössls. Like most
astronomical equipment, their price second-hand in France is similar to
the price you would pay for new in the U.S. I paid those in the 70 to 80
which is around 75 - 85 US$. I purchased them from different people but
all were in good condition. I wanted to try them because Vixen has a great
reputation in Europe, which I guess is because Japanese brands were in
Europe before the Americans.
Just Looking - Outer Assembly
The construction of the eyepiece seems
very durable. The outside is a rubber-like plastic, but mine do not have
nail scratches you would imagine on that kind of material after a certain
time. The rubber eye guard stays put and seems an extension of the barrel.
When you shake the eyepiece, you don't hear any lenses or internal parts
wiggling inside (it is a good thing
because I do not have a clue on how to open these eyepieces). The eyepiece
is only marginally heavier than a comparable Plossl, which is a huge
advantage if you have a difficult to balance telescope, a shaky mount or
cheap focuser (which too many of us have). I have only one complaint: on
all four samples, the eye lens cap is too loose and falls off easily. I
find it really irritating when putting eyepieces in my pocket, or when
carrying the eyepices in a pouch. The solution, which I would recommend,
is instead of using the old-fashioned foam-lined eyepiece case, is to find
in a hardware store the plastic cases they sell to keep together nuts,
bolts, screws, etc... I found one where the little compartments are about
the size of my eyepieces and am not looking back (I hated the foam-fitted
cases because they tend to gather dust, and after a few years the foam
starts decaying and leaving bits of hard foam everywhere). Also, all
eyepieces come with a ring of a different color to help identify them, but
of course in the dark you will not see these colors. What will help you is
that the shorter the focal length, the taller the eyepiece.
The unusual part is you do not have a
visible field stop on the field lens side, you just have a somewhat narrow
field lens (and looking very convex, like the eye lens of an Orthoscopic)
held by a black plastic ring. I would be worried to have to clean the
The eye lens looks about flat and is
15 mm wide on all models. Mine are inexplicably clean. I think the eye
guard plays a role in keeping dust and stray eyelashes away.
Let's Duke it Out
I tested these eyepieces against, on
the budget side, my budget Plossl eyepieces (Adorama / ProOptic and some
Chinese e.p.s so generic there is just the focal length printed on them)
in 7.5, 10, 16 and 20mm FL, 26mm Celestron Plossl, 9mm Plossl and Meade
Orthos, and on the my
kids-are-still-15-years-away-from-college-side, my 8 and 12mm Radians (in
flagrant violation of this website's mission statement). I tested them on
my Meade 826 (the 80's 8" f/6 Newtonian, still a great tube) and my
Takahashi 90 (another violation of the aforementioned statement, but I
promise I do not have another telescope out there).
First observation on observing with these eyepieces: they are not parfocal
at all. The ProOptic's are not parfocal but close enough not to bother
re-focusing all the time; here you really need to refocus to see anything.
It is a little upsetting for what is marketed as a premium eyepiece,
especially with my 8" which has the deadly combination of shaky mount
Second observation: even before talking of the quality of the image, the
view is pleasing. You automatically see the entire 50° FOV, without
ghosts, reflections or blind spots. There is no strain at all in looking
through these oculars.
Third observation: ok, now the eye guard is a little long for me. I tend
to bump my eye on it to see well the whole FOV. When it bugs me I roll
down the eye guard.
I quickly stopped comparing with the Radians, only using them for checking
purposes. There is no miracle there: they walk all over the Lanthanums.
They are sharper, the field looks clearer, is wider (60°), and are
parfocal. Their only drawbacks are those little blackouts (kidney beans),
their weight, and of course their big price tag. A good indicator is that
I consider them better than the Lanthanums, but I end up using the
Lanthanums more often.
These eyepices work well on planets
(here, Jupiter and Saturn at opposition). In good seeing it is obvious the
Lanthanums are sharper than the Plossls. I cannot detect false color other
observers report. I can, however, note that when looking at Jupiter the
background is not that dark; you do not "see" the reflections
but there is some light scattering going on. The view is less pleasing but
it does not disturb viewing in my opinion.
The 4, 9 and 12 are on par with the Celestron 9mm Ortho (which is an
under-rated eyepiece by the way); a little under the 8mm radian in terms
of contrast and sharpness. When looking at Jupiter, if you wait long
enough for those fleeting moments of perfect seeing, the details around
the Great Red spot in the 8" are a treat. Let's add that they work
well with Barlows,
except perhaps for the 4mm: you tend to have a little white halo around
objects. I think it's mostly due to the fact that focus has to be
super-sharp with the 4mm. They are probably not better than in the Orthos,
but the deciding factor is this: as the view is more comfortable, you can
spend 20 minutes on the same target at the eyepiece waiting for the skies
to be steady. After 10 minutes looking through a 4mm eye relief Ortho or
Plossl, I have cramps, my eyes are strained and I feel like kicking the
mount, which can't be good for your polar alignment.
At medium power (the 12mm gives 100x,
the 9mm gives 133x) the views are pleasing and sharp on star clusters, the
contrast good for nubulae and galaxies. Panning while looking for objects
with the 20mm at 60x or the 12mm at 100x is pleasant as you really feel
like viewing through a flat window. With the Tak, with its 500m FL, the
magnification goes all the way down to 25x, and large objects like the
Pleiades make you wish to press on a "take picture" button. Here
these eyepieces are much better than the budget Plossl because the whole
field seems in focus at once; with the Plossls (not the 26mm Celestron), I
often have the feeling that some areas of the FOV are in focus while some
are out, or that the position of my eye relative to the
eyepiece affects apparent focus. I do not know if you have seen this
effect already. The only eyepiece on par was the 26mm Plossl, which is
sharp and not bothered by eye relief problems.
Winners and Losers
The short FL Lanthanums are winners,
because they are sharp and have long eye relief. There does not seem to be
much choice in the under-$100 range for quality long eye-relief eyepieces.
They will not be sharper than quality Orthos and Plossls in the same price
range, but their comfort of use is a reward in itself. The relative loser
is the 20mm (and it seems to be discontinued anyway, I do not see it
advertised anywhere). You could buy it to complete your set but alone
there is not much point I think in having one. You are better off with a
quality Plossl in that FL range I think.
Submitted by Mattieu Chauveau - firstname.lastname@example.org
- Northern France