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Nagler vs Radian

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#1 Warren914

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Posted 10 December 2012 - 06:06 PM

Other than a smaller field of view, what difference will I see between a TeleVue Nagler 3.5mm and Radian 3mm or 4mm eyepieces? Will one produce a sharper or better image for planetary use? What are the advantages / disadvantages of each one? Would the Radian give a better image compared to the Nagler 3-6mm zoom?

#2 GeneT

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Posted 10 December 2012 - 10:36 PM

One major difference will be that the Radian has 20mm of eye relief vs. 10 for the Nagler zoom. The Radian is a fixed mm eyepiece. I prefer fixed mm eyepieces, because in my opinion, they yield slightly sharper images. However, many love the zooms. If you are thinking about a Radian, I recommend you think about a Delos instead. They are 72mm AFOV vs. 60 for the Radian. I also find them to provide sharper images. I hope to put my Radians and Delos in a shoot off when I an get a free evening. Jupiter is nicely placed, and I like to make these comparisons with either Jupiter or Saturn in the equation.

#3 bdcmd

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Posted 11 December 2012 - 02:09 AM

I find the 3-6 Nagler zoom to be slightly sharper than the Radians at comparable focal lengths. The zoom is also very useful in determining the optimum magnification usable on any given night, especially for planetary viewing. However, for any lengthy viewing, the 20mm eye relief of the Radians more than makes up, in overall comfort for long term viewing, for any miniscule difference in on or off axis sharpness compared to the 3-6 NZ. I don't have the 3.5 Nagler, but do have the 5T6, 4,5,6 Radians and the 3-6 NZ to compare. The Nagler has the wide field, is very sharp, with about 10-12mm eye relief, binos well; the Radian has a narrower field, still very sharp, 20mm eye relief, also binos well. The zoom has shorter eye relief, is very sharp on axis, and not at all bad off axis, but allows you to nearly instantly determine the optimum zoom focal length usable on any given night, for any given target. I use the zoom to set the parameters, the Nagler to get the wide field views with maximum surrounding context and contrast. I use the Radians for long term viewing of a single object for detailed study, to learn the most I can about it on a single night in a given scope. They cause me the least fatigue and allow me to observe for hours at a time if necesary. Each has a use, somewhat complementary to the others. I use them all, most nights, to get the most information from each type, according to the objects being viewed. By the way, I use several types of telescope: an f/11 C8, an f/4.8 ES Comet Hunter and a couple of f/7 to f/9 refractors,I think trying the Naglers would definitely give you a different perspective in certain types of astronomical targets.

#4 Paul G

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Posted 11 December 2012 - 06:14 AM

Nagler zoom review

5 Radian vs 5 Nagler

I have all three and the only real difference I see is in fov. Like Richard Orr said you can back off from the Nagler to a longer eye relief and have the fov of the Radian. OTOH, although the fov is smaller the ability to exactly match the magnification to the seeing makes the Nagler zoom extremely handy. I haven't tried a Delos yet. Best approach would be to try all three, either at a star party or club observing session, or buy them used off the Mart and sell the ones you don't prefer at little to no real cost. Your scope-eye-brain combination may favor one over the others, and the ergonomics of one may just "feel" right to you.

#5 george tatsis

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Posted 11 December 2012 - 07:15 AM

Don't have the Naglers anymore, but I still have the Radians and the Nagler Zoom 3mm-6mm. For planetary observing I stick with the zoom, as there is no difference whatsoever between the zoom and the Radians.For lunar I prefer the Radians, because the LER enables me to view the whole field and get the porthole window effect.

The T6 series is neither of the above. You can't dial in the right magnification as you can with the zoom, nor do you have the ability to view the whole field as you can with Radians. Sure , the T6 Naglers are a 82* design, but how much of it can you see in one shot without having to turn your head around? YMMV though, as they are all excellent eyepieces with 99% similar views.

#6 Warren914

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Posted 11 December 2012 - 08:02 AM

Seems bottom line is that the zoom is a very good eyepiece that looks just as good as the others. Slightly less fov but smaller and essentially several focal lenghts in one. It's in my collection already, so hardly worth the expense to get the Radians. Money can be put towards something else. :)

#7 BillP

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Posted 11 December 2012 - 09:35 AM

Other than a smaller field of view, what difference will I see between a TeleVue Nagler 3.5mm and Radian 3mm or 4mm eyepieces? Will one produce a sharper or better image for planetary use? What are the advantages / disadvantages of each one? Would the Radian give a better image compared to the Nagler 3-6mm zoom?


My eye finds the Radian to give a better planetary image than the T6. Better contrast and definition. I also like the virtual lack of Rectilinear Distortion off axis that the Radian has compared to the T6. The 3-6 Zoom is definitely nice, but the FOV is small. If a 3mm or 4mm eyepiece produces very high magnification in your scope, then I would opt for the Radian over the Nagler Zoom for its larger FOV. I would also opt for the Radian over the T6 because I like its tone better (not as warm as the T6s) and feel it gives a slightly crisper image for planetary. If this very short FL eyepiece is for more than planetary and will produce high magnifications, then the 82 degree AFOV of the T6 trumps all other considerations as the extra context over the Radian or the NZoom is well the trade off for a slightly warmer and slightly less than perfect planetary image. All a matter of compromises and priorities.

#8 PeterWar

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Posted 11 December 2012 - 02:07 PM

I've found the T6 3.5mm Nagler to be superior to the 4mm Radian in terms of ghost image surpression, but eye relief on the Radian is just more confortable, I don't like the current eyeguard and eye relief of T6 Naglers.

I agree with GeneT, if the 3.5mm Delos is as good as the 6mm, you'll probably better off investing in the Delos than in the Nagler or the Radian.

Mind that Radian coatings may vary according to the year of production. The Delos design is the latest, that means better coatings.

#9 ibase

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Posted 11 December 2012 - 08:00 PM

Some time back I debated which Televue EP to get for the 5mm slot; in consideration were the Nagler 5mm T6, Radian 5mm or TV zoom 3-6mm. Ended up with the 5NT6 because the field of view of the latter 2 were only 50-60 deg. while the 5NT6 was a "spacewalk" 82-deg., quite a big jump from 50-deg. Not willing to pay as much money for 50-60 deg. TV EP's, but I do have the TV plossls (8, 11, 15, 20, 25, 32mm pair) which at around $100 each was for me a fair price for 50-deg. TV EP's. The eye relief of the 5NT6 at 12mm was also just right from my eyes and performance wise, the Nagler 5T6 is no slouch (perhaps splitting hairs differentiating it from Nagler zoom/Radian on axis). Also have a Delos 6mm which at 72-deg. AFOV is considered as a widefield EP just like the Nagler 5T6, so it's worth the money. All just my 2 cents of course, YMMV.

Best,

#10 Knygathin

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Posted 25 January 2013 - 10:54 PM

Is it true that you can unscrew the barlow on the bottom of a Radian and thereby get a 100 degree AFOV?

#11 Scanning4Comets

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Posted 25 January 2013 - 11:44 PM

No to the above.

#12 Knygathin

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Posted 26 January 2013 - 06:16 AM

Ed Ting refers to Al Nagler having shown him this. Stated in Section 9) of link below:

http://www.scoperevi...com/page3b.html

#13 Jim Romanski

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Posted 26 January 2013 - 12:10 PM

I've heard that you can do this with some eypeices that have a barlow/smyth type lens at the bottom. As Al said though it doesn't mean you'll have sharp star images.

#14 Jim Romanski

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Posted 26 January 2013 - 12:20 PM

My eye finds the Radian to give a better planetary image than the T6. Better contrast and definition. I also like the virtual lack of Rectilinear Distortion off axis that the Radian has compared to the T6. The 3-6 Zoom is definitely nice...

I see the same thing as Bill does. I like the Radians on planets and especially on the Moon. Normanlly the lack of Rectilinear Distortion isn't important to me. But on the Moon it can really help reduce the "fun-house" effect as you scan around the lunar disc.

Usually, I'm like Gene in that I prefer long eyerelief eyepieces. But at very short focal lengths which produce small exit pupils (<1mm) I don't need them to correct for asigmatism. I have a Pentax 5.1mm XO and don't mind the extremely short eyerelief. But it's still nice to have the longer eyerelief just to avoid the hassle of taking my glasses on and off.

I'm actually getting ready to sell my 5mm Nagler and keep the 5mm Radian.

#15 dscarpa

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Posted 26 January 2013 - 07:34 PM

I have 3 T6s and used to have 2 Radians. I found sharpness and contrast about the same which is to say very good, both are warm toned. To me the T6s have more clarity and I found the Radians easier to use. Putting 2" eyecups on the T6s made a big improvement in easy of use. David






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