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Vixin Lanthanum 4mm, 9mm, 12mm, and 20mm 

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Date: 5-27-2003
Price: approx. $100.00 - 125.00 each
Design: Set of eyepieces that contain the rare earth element Lanthanum and featuring 20mm eye relief.
Description: Quality eyepieces in a mid priced bracket.

The Reviewer

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 mathieuchauveau@hotmail.com

The Purchase

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 Euros range,
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.

Field Lens

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 field lens.

Eye Lens

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 and
rough focuser.

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.

Planetary Targets

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.

Deep Sky

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 - mathieuchauveau@hotmail.com - Northern France

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