A review by Todd Gross Updated.. 08/31/01
JULY 1999 UPDATE: The Nagler 22mm is reviewed below!
NOV 1999 update: The Nagler 31mm is reviewed below and the Nagler 17mm is reviewed below.
June 2001 Update: The new Nagler 5&6 line is coming out. I have reviewed the 9mm type 6 below.... and the 16mm type 5. Both have limited eye relief, but are solely 1.25" eyepieces suitable for binoviewers.
Aug
2001 Update: EXCITING New "Nagler" is the 3-6mm Nagler Zoom. MUCH DIFFERENT
than other Naglers, but a fantastic planetary eyepiece. See below.
________________________________________________________________________________________
The Televue Nagler is perhaps
one of the most sought after eyepieces ever, and with good reason. The
wide 82 degree apparent field features images that are sharp just about
to the edge in most telescopes... considering how large an 82 degree field
is.. that is amazing. The feeling of "openness" is refreshing, and quite
different from even a 50 degree apparent fov eyepiece.
Al Nagler, the creator of this line of eyepieces, calls the feeling one gets when viewing through them, a "space-walk". This is something new to visual astronomy, but it is real. The effect is this: When viewing through a Nagler, particularly from 9mm on up through 20mm, you can barely take in the whole field at one time. The result is that you have to move your eye and/or you head around to truly absorb the whole view. While this can be disconcerting at first, when you are relaxed, and casually observing, you can really get a warm feeling of being able to "look around", or concentrate on different parts of space without having to move the scope. It is like looking out of a porthole on the Starship Enterprise!
The disadvantages of the Nagler eyepieces are few, but they do have some drawbacks. Contrast is high, but there is a tad less light throughput due to the multi-elements. Also, some observers claim that contrast and internals reflections are not quite as good as on simple eyepieces like Orthoscopics. In addition, I have found that unless you take in the entire field of view at once by getting in very tight to the eyepiece, you might sometimes run into a slight "ring of brightness" around the edge of the field, not visible in some other eyepieces such as the Televue Radians. Pin-cushion distortion, which is most pronounced on the Panoptic line, is no stranger to Naglers either. Straight objects like trees will look bent at the edge of field when viewing by day. This is somewhat reduced in the latest Nagler 4 line.
The other disadvantages lie within specific eyepieces, and I will go over those below. Note.. I have written this over a course of several years, so if there are any contradictions, please forgive me ! I start out talking about the only "non-nagler-like Nagler", the 3-6mm Nagler zoom.
A huge advantage in dealing with Televue eyepieces, by the way, is that they can be returned for repair! I sent in a useless 9mm Nagler, and had it returned in just over a week, good as new. The repair was reasonably priced.
Here is a summary of
the Nagler line:
Best of all...the eyepiece requires ZERO refocusing as you zoom, and the quality of the view is as good if not better than the quality planetary eyepieces I put it against. (Pentax Orthos, Televue Radian) The only problem at all I found was when I moved Jupiter or Saturn just outside the field of view, I could catch a little more glare as the planet approached the field. It only lasted for a split second when the planet fell in a certain location. However, contrast was slightly better in this eyepiece compared to the Pentax Ortho 6, which surprised me. (Example: better rendition of Saturnian moons due to darker sky)
At first, 50 degrees seems a bit limited in apparent field of view, but you can effortless turn the power down to widen your field size if you want to take in more field for finding the object, or seeing the lunar orientation around the planets, etc.
More later...
The 4.8mm Nagler.
This eyepiece exhibits short
eye relief, approximately 7mm. It also does not give much of that "space-walk"
feel compared to the longer focal lengths. Views are sharp though, if you
can keep the lens clean. The field is very wide, but not as comfortable
as viewing with the longer Naglers. The latest version includes a full
eyecup rather than the "horn" type previously supplied, and I believe a
grip ring.
The 7mm Nagler.
This eyepiece has a more
reasonable 10mm eye relief. Also supplied with a very stiff, roll-down,
full eyecup (like the 4.8mm) which is very effective, even more effective
than the 9 Nagler and up. However, it doesn't roll down easily, and makes
it somewhat harder to go from glasses to without glasses, and back.
The view is very pleasant and wide, much more comfortable than the 4.8, and a bit more of that "space-walk" feeling. You only have to move your eye around, and not your whole head to take in the full 82 degree apparent field of view. On most scopes, this is a fantastic planetary eyepiece. Both the 4.8, and the 7mm Naglers are pure 1.25" eyepieces, and are suitable for 1.25" diagonals, and/or binoviewers.
The 9mm Nagler.
This is the first in the
series to exhibit the Nagler's more typical qualities. This eyepiece is
a small 1.25"/2" hybrid design. It is a 1.25" eyepiece with a 2" "skirt".
It fits more securely in a 2" diagonal, but works just fine in a 1.25".
The eye relief is better, approximately 12mm.
The "space-walk" feeling is full blown. The design of this and many of the Nagler's has changed so many times over the past few years it is mind blowing. From buying them second hand, and trying to match them for a bino-viewer, I have been driven nuts trying to keep track of the excellent alterations. The latest 9mm Nagler (and I believe all the others on up from here) features an easy to roll down eyecup, a contoured barrel (like the 7 and 4.8 versions feature too - apparently to prevent eyepiece falling accidents), a grip ring, and a new placement of the top element..right on the plane of the top of the eyepiece (not at all recessed) allowing for a more comfortable eye relief, but a higher probability of eyelash contact.
NEW: The 9mm Nagler Type
6:
Like the 9mm Nagler (type
1) above, the type 6 has fairly short eye relief, but is useable (barely)
with glasses. It features excellent planetary performance, despite what
some may tell you (I've been testing on Mars) and a huge field of view
with stars sharp to just about the edge of the field. There is some lateral
color (false color becomes visible as you move bright objects towards the
edge). There is a slight kidney bean distortion (that is, mostly by day,
you may notice some minor blackouts as you move your eye around.) The difference
between the 9mm type 6 and the type 1 is mainly that this is SOLELY
a 1.25" eyepiece. Although an 82 degree apparent field of view is overkill
for a binoviewer, this eyepiece is small enough
and light enough to be used in the Televue Binovue (or any binoviewer)
effectively. It is about the size of a 19mm panoptic (this is slightly
skinnier but slightly taller than the 19mm pan.) I love my 9mm nagler type
6 as I generally stay away from the heavier eyepieces. There is no real
need for the 2" skirt.
The 11mm Nagler
No longer being produced,
this eyepiece is considered a "collector's item", and draws big bucks on
the second hand market. No, I have never tried one, but apparently it does
not come with an eyecup. The 11mm Nagler is the Nagler 1 style, like the
4.8, 7, 9, and 13. From 9mm and up there is a slight "kidney bean blackout"
effect, but it really isn't noticeable until you reach 13 (some say the
11 too), which we will discuss shortly. I have not heard that this Nagler
is any "better" than others despite the high price it draws. It is considerably
heavier than the 9mm, and also apparently is a 1.25/2" eyepiece.
The 12mm Nagler "2"
When you get up around 13mm,
the Nagler 1 design exhibits a more pronounced "kidney-bean" blackout effect
discussed below. Therefore, Televue created a new design, similar to the
1st, which allowed the Naglers to go all the way up to 20mm, without any
of the problems associated with the earlier design. The only trade off,
is eye relief. While the relief is limited, the placement of the top element
right at the plane of the eyepiece makes for very comfortable night-time
viewing without glasses, even with the eyecup rolled up. However, with
glasses, it is somewhat tight, and you will lose some of the f.o.v.
I have sold, and re-purchased
this eyepiece many times, always "missing" the huge panorama, and yet sharp
planetary images. I could be mistaken, but the app. field of view seems
even larger than 82 in this particular model. I use this eyepiece especially
for observing globulars in an 8" or 10" SCT. Perfect mid-high magnification
eyepiece to see the whole globular, and it's "context" yet break down the
individual stars! This eyepiece is quite heavy, and also features a 1.25/2"
hybrid design.I would recommend a 2" diagonal to hold it for security.
I had trouble, by the way, seeing the whole field by day...for some reason
it was easier to take in at night, must have something to do with pupil
size. The 12mm Nagler 2 and the 13mm Nagler 3 have been recently discontinued..
The 12mm Nagler "4"
Released late March,
1999
The 12mm Nagler 4 is almost
like taking a Nagler 2, 12mm, Nagler 1 13mm, and 12mm Radian eyepiece and
combining them into one! The design is different.. with a convenient clickstop
up-down sliding eyepiece housing that allows you to easily adjust for glasses-on,
glasses-off use. I found the supplied "pupil guide" which helps you determine
where you should place the clickstop of the eyepiece a bit confusing. The
clickstop sliding style seemed loose in both eyepieces I tried, not as
secure as the Radian. The eye relief is better
than the old Nagler 2, but still a bit tight with glasses if you want to
take in the whole field of view. In addition, the kidney bean distortion
of the Nagler 1, 13mm is back... that is, if you try to take in the entire
field at once, you end up increasing the kidney bean blackouts (in other
words, you have to hold your head steady to avoid some blacking out.. not
good for newcomers) The blackouts were far more pronounced than on the
Radian line, which is easier to eliminate by adjusting the barrel (it is
a different effect on the Radians and very slight) The view was tremendous,
I had to push very hard to see any difference between the excellent Radians
and the 12mm Nagler. The Radians may have been a tad more contrasty, but
again, any difference was barely noticeable on M13 and Mars. The real field
of view (actual amount of sky seen) of the 14mm Radian was just about the
same, only slightly less than the 12mm Nagler 4. It really depends on the
mood of the observer. The new nagler 4 is not very good by day. Additional
kidney bean distortion and pincushion distortion (bending of straight objects
near the edge of view) make it a night-time wonder, and a daytime flop.
The edge of field clarity, by the way, was unbelievably excellent in both
an f/7 and f/10 scope. Without the pincusion effect I doubt this would
have been possible to achieve. It really is amazing to see absolutely no
loss of clarity across such a huge field of view.
Here is a report from Paul Gustafson and his experiences with this fine
eyepiece.
Stats for this eyepiece:
12mm
Field stop = 17.1mm
Eye relief = 17mm
Elements = 6
Barrel size = 1.25"/2"
Weight(lbs.) = 1.1
The 13mm Nagler
The last in the series 1
Naglers, the 13mm is perhaps one of the finest, and yet it has an infamous
problem: The Kidney Bean effect...which incidentally is far worse by day
than night. Essentially, these kidney shaped, blackout areas become prominent
as you shift your view around to take in the whole view. (similar to a
blackout when you get too close to a 40mm eyepiece) I have seen it claimed
that if you naturally hold your eye steady, then you will not have a problem.
Well, that is true, but you will also only be taking in 70 degrees and
not 82 degrees, or thereabouts, (varies with observer) and that is what
you are paying for. However, this eyepiece, also quite large, exhibits
a very comfortable view, and good eye relief compared to the 12mm. I believe
it is rated at about 19mm relief, but I found it shorter, especially when
trying to view the edge of field.
This eyepiece is fantastic on deep sky, giving a real Oh-wow feeling. On Jupiter, I believe the sharpness on the bands was not quite as good as on other eyepieces, but I discovered that in a pretty quick and dirty test session, so I could be wrong. In a side by side test against the 12mm Nagler, I thought I detected a bit more "life" and brightness to the image through the 13, but it could be because of the additional 1mm focal length. Note, that on this Nagler, as in many others, there is already a "built-in" Barlow! This can be unscrewed, to gain a 30mm eyepiece or thereabouts, but I wouldn't recommend it. Firstly, the stars at the edge of field suffer greatly, and secondly, you risk ruining your eyepiece, especially since it isn't easy to screw and unscrew the built-in magnifier. (this is a hot topic, unscrewing the Naglers, in our Meade User Group)
The 16mm Nagler 2
Almost identical in design,
size, weight, and viewing characteristics to the 12 (indeed the 16 is slightly
SMALLER than the 12, go figure), the 16mm Nagler 2 is an awesome deep sky
and planetary eyepiece. The space-walk, eye relief, and just about everything
is identical to the 12. Some folks have reported some "ghosting" of bright
objects with this eyepiece. I do not recall any at all.
The 16mm Nagler "type
5"
Initial notes: Very small,
1.25" eyepiece, compared to other Naglers. Almost the same exact size as
the 19mm Panoptic, but a bit heavier, still it looks like it will be great
in binoviewers, although a bit of "overkill" for that application (although
some users like wider field of view while binoviewing (not me)).
There is NO kidney bean distortion, or black out areas of any kind as you
move your head around, but only 10mm eye relief, meaning you cannot take
in the whole field with glasses.
Observing report: Excellent resolution, and sharpness to the edge, but pincushion distortion as expected is utilized (straight objects look bent) so not a great daytime eyepiece. Also, vignetting is noted in all scopes to varying degrees towards the very edge of field. (darkening). Eye relief is fine for me without glasses, but at 16mm, since I have astigmatism, only scopes of f/8 or longer are producing the under 2 mm exit pupil that is required to limit my astigmatism, keep that in mind. With glasses, the ep is useable , but not as "friendly" as the Radian line. The view is very similar to the 16mm Nagler type 2, except this is a pure 1.25" eyepiece, not a hybrid. There is a blue ring at the very edge of field that you can notice while viewing the moon or bright objects only. I spoke to Televue about this and they said they allowed this slight negative to offset having to include another element. I personally prefer the greater eye relief of the Nagler 17mm, but that is a 2" eyepiece only.
The 17mm Nagler 4
Stats:
17mm
Field stop = 24.3mm
Eye relief = 17mm
Elements = 7
Barrel size = 2"
Weight(lbs.) = 1.6
Available: Summer, 1999
I have been loaned the 17mm
Nagler 4 by Steve Viltoft for a couple of months. Thanks Steve! The bottom
line is if I had a fast reflector, and could only own just ONE eyepiece
+ ONE barlow.. this would be the eyepiece. The eyepiece is fairly heavy,
about the same size and weight as the 22mm. Other than that, this TWO inch
eyepiece (can't use it in a 1.25" diagonal or focuser) is marvelous. Sharp
to the *almost* the edge in an f/8 refractor, and just slight definition
loss towards the edge in an f/5 reflector (with Parracorr in place, more
noticeable than in the refractor). In an f/10 SCT,like the refractor, if
you look real close by moving a double star or globular to the edge of
the field, you will notice a slight loss in definition that is not noticeable
in the 19mm Panoptic. Larger real field of view than a 19mm Panoptic, and
more definition on objects such as M13 (partially due to higher magnification,
not performance). Some "color" as in most naglers (and most eyepieces in
general for that matter) towards the edge of field on bright objects (purple
tinge) No substantial "blackouts" of any kind (kidney bean or from high
eye relief). While this was not a problem for me on the 22mm , I was able
to recreate the blacking out on the 22 that some other folks reported by
setting the eyecup in the wrong place.. on the 17mm, it's even harder to
induce any sort of blacking out. On-axis very sharp. Eye relief is large,
more than the 19mm panoptic, seems about 18mm. The result is the ability
WITH glasses to take in the entire field of view for a fabulous "space-walk".
This really, really helped, since I need glasses until around 10mm for
my astigmatism. I highly recommend this one. Written: 2/2000
The 20mm Nagler "type
2"
This is a huge, heavy eyepiece,
up there with the 35mm Panoptic in size, and weighing in in pounds, and
not ounces. Some telescope owners can't afford that extra weight. Also,
it is a 2" eyepiece, there is no provision at all for a 1.25" focuser/diagonal
unlike the other Naglers. The wide top lens seems to make for a very comfortable
viewing experience. However, like the 12 and 16, you shouldn't use this
eyepiece with glasses, unless you are willing to sacrifice a chunk of field.
Again, a similar, approximately 10mm of eye relief. The space-walk feeling
is at it's maximum with this eyepiece as you have to shuttle around a lot
to take in the whole picture comfortably.
This is one of the most important eyepieces around (and expensive), as it will give you as much field size as a 32+ mm Plossl, and yet give you a substantially more magnified, intensive view (although potentially dimmer as the exit pupil is smaller, but the contrast factor often makes up for that). If you buy this eyepiece for instance, and replace your 26mm that comes with your telescope, you will gain BOTH substantial field size AND magnification all in just one eyepiece. Indeed with a fairly high powered telescope, such as an 8" f/10, I probably would choose this eyepiece if I could choose only one (and no barlowing allowed, with a Barlow I would probably choose the 27mm Panoptic if I was allowed just one!)
The 22mm Nagler "type
4"
Field stop = 31.1mm
Eye relief = 19mm
Elements = 7
Weight(lbs.) = 1.5
PRELIMINARY REPORT
Oh my! I opened the box
with the 22mm Nagler 4 that I bought from Anacortes while I was on the
phone with s.a.a. member Bill Charash. I popped it into the traveler on
a rainy afternoon, and was stunned. Even by day, the eyepieceimmediately
showed off it's stuff. Sharp, sharp, on-axis views, contrasty, high eye
relief, easy instadjust eyecup so I could go with or without glasses, HUGE
apparent field of view (82 degrees) with only minor pincushion distortion
DESPITE sharp views to just about the edge of field. (but not quite)
No kidney bean distortion. I expressed my disbelief to Bill on the
phone.
The eyepiece weighs 3 oz. less than a 35mm panoptic, & I'd guess around 13 oz. less than the old 20 nagler. It is about 2/3 the size of the old 20. (I came up with 1 lb. 7.5 oz, compared to 1 lb. 10.5 oz for the 35mm Panoptic on my scale) It's still quite large. A tad larger than the 12mm Nagler 4.
Afterwards, I took the eyepiece out to some of the best dark-starry skies I have seen at my site in weeks, (LM around 5.4, milky way prominent) as skies cleared during the early morning hours. I did an extensive comparison to othereyepieces, but especially to the 35mm Panoptic, for the purpose of deciding which one to keep. (Can't afford two ultra-premium eyepieces) There is no doubt this is THE best Nagler ever. Resolution and contrast were superb. Compared to the 35mm, in a fast reflector with a Parracorr, objects were much more magnified, but the field of view just a bit smaller. Thus, detectability of detail and faint stars was much more evident in the 22, as one would expect. M2 was almost fully resolved in the 22, and yet not at all in the 35mm. (again due more to magnification than anything else.) However, broader objects surprised me. The Veil Complex (ngc6960 section) through an OIII filter showed much more detail AND even appeared brighter (a contrast illusion) in the 22 as it snaked past 52 Cygnus. More threads, more stars. The 35mm Pan. framed M31 better, but showed significantly fewer stars there as well.
Most of the above is purely because of the additional magnification, a more fruitfull comparison would be to a 21mm pentax or 22mm Panoptic in terms of sheer on-axis performance. I also need to compare in various scopes of all kinds. HOWEVER, I will say this. At night as well as by day, the tremendous wide field of view can be taken in with, or without my glasses. (I have a fairly thin pair keep in mind) It is just an astounding sight. No evidence of black-out areas (due to kidney beaning or any other process) and sharpness to almost the edge of field even at f/4.8 (May have been residual coma from the scope) In addition, my eyes were tearing during the comparison ( they sometimes do when I first get up ) and that often causes fogging of the eyepieces, but the eye relief was wide enough that that was not an issue with the 22. If one has to own just one eyepiece, this is it. Despite the price (mid 400s) my initial recommendation would be to buy this and sell other eyepieces to fund it. If I had no other choice, I would use this with a 2" barlow, rather than own a separate 12mm Nagler or Radian. Al really hit a homerun with this one. More to follow..
7/23 Update: I have tried the eyepiece in numerous scopes now. I have come to a further understanding about what sets this eyepiece apart (other than price, unfortunately ;) ) The eyepiece is sharp to around 85% out towards the edge of field, much like other Naglers, some people tell me they feel the old 20mm Nagler was sharper at the edge. Not quite to the edge like the new radians, but afterall, this is an 82 deg. apparent field of view. (Feb 2000 note: I do feel the 17mm is a bit sharper towards the edge.) The view "pops out" seemingly right out of the eyepiece, due to the greater eye relief. This is similar to the 13mm, but the 13mm, has problems for some folks with kidney bean blackout areas. This "Television-like" view is really quite superior in my opinion. You have to still "look around" to take in the whole field of view, since some remains on your peripheral vision, just like a standard Nagler and the "space-walk" feel to them. However, even though some folks don't quite "feel" as much "spacewalk" with the Nagler 22, I think they are just reacting to having ample eye relief, so it's not as difficult to take it all in!
11/25/99 Update: Some observers are reporting that they are having difficulty with kidney-bean like 'blackout' areas with this eyepiece. While I have not found this to be a problem myself, and adjust the eyecup accordingly, it should be noted. See 17mm nagler discussion for more info. on this above.
31mm Nagler 5:
The Nagler 5, 31mm is quite
an eyepiece. Like the type 4 series, we are dealing with good eye
relief, enough with my thin pair of glasses at 19mm, and the standard jumbo
82 degree AFOV. There is no slide up and down eyecup like in the type 4
series, but I found no difficulty with blackout areas or adjusting the
fold-down eyecup to allow for glasses or non-glasses use. Milking out almost
the widest possible field for a 2" eyepiece, the 31mm is ideal for fast
scopes that gain little benefit from eyepieces 35mm and above due to exit
pupil considerations. The one drawback to this eyepiece is it's weight.
At 2.2 lbs, it is just too heavy for some scopes to balance. Others can
take the weight easily. It's also the largest eyepiece I've ever used in
physical size, and barely fits in my eyepiece case, being a good 50% larger
than the 22mm Nagler 4. Very sharp on-axis performance. Some lateral color,
like the other naglers, but not very objectionable. Sharpness towards the
edge of field varies scope to scope but is quite good. Using a reflector
and a Parracorr, stars lose almost no focus or clarity going right to the
edge. Using an SCT at f/10, they do suffer towards the edge of field a
little bit, but is noticeable mostly in testing, not in use. This is similar
ot the 22mm Nagler 4. I was surprised to be able to pick out many moons
of Saturn even at the low magnification through this eyepiece in partly
cloudy skies. Tiny little pin-pricks tipped me off to it's sharp on-axis
performance. Should one choose this eyepiece over the 35mm Panoptic? That's
a tough question. At $595.00 this costs more, and is a bit heavier and
larger. On the other hand.. the additional magnification without sacrificing
real field of view will help resolve most objects, and is particularly
helpful to faster scopes. It's a tough call! From memory, compared to the
30mm Leitz this is a heavier eyepiece with similar performance, although
I believe the edge is somewhat sharper with this eyepiece, at least in
my reflectors using the parracorr. Overall, a superb effort and long awaited.
At last it's here!
11/25/99 Update: This eyepiece
was no doubt inspired by the Leitz 30mm, another great eyepiece.
Bob
Luffel compares the two.
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