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12mm Nagler Type IV

Started by Richard Beasley, 08/05/2006 05:36PM
Posted 08/05/2006 05:36PM Opening Post
Are there any users of the 12mm & 22mm type 4 Naglers here? I have the 22, but never have used the 12. The 22 is the only eyepiece I have used where I felt I was going to fall into the FOV. Is the 12 the same in that regard?

Thanks in advance,
Posted 08/05/2006 06:09PM | Edited 08/05/2006 06:10PM #1
The 12mm Nagler is quite nice, I have it, the 17mm T-4 and the 22mm T-4. They all have a very immersive view. The 12mm is not quite as immersive as the 22mm, but that is because the total FOV is smaller I feel. It does have a more spacewalk feel than the 13mm T-6 in my opinion.

[SIZE="Large"][/SIZE][COLOR="Blue"][/COLOR] Floyd Blue grin
Amateur Imager
Posted 08/05/2006 09:12PM #2

At one time or another I've owned/used every Nagler eyepiece model ever made with the exception of the 20mm T5. I know what you mean by the special immersive/fall- into-the-field feeling that you seem to get with the T4 series.

If you're wondering if the 12mm T4 will perform in the same league as the 22mm T4 (and hence would it be worth getting one), then my answer would be yes to both of those questions.

While the apparent field of the 22mm & 12mm T4s are the same, the true field is 82% wider and that in turn results in the 22mm T4 having a 231% larger total field area. So for rich field scanning of the sky the 22mm T4 has some obvious advantages and it can give you more of an immersive feeling depending upon the fields (and objects within) that you are looking at.

However, the 12mm allows you to view a field (albeit with a smaller in true field size than the 22mm) at 82% higher magnification than the 22mm will allow. That higher power in turn results in a smaller exit pupil and a darker sky background (which improves the contrast)as proving a significant enlargement in image scale. Therefore, for many objects/fields those attributes (of the 12mm T4) give it advantages over the 22mm.

Of course a higher power 12mm Plossl or Radian eyepiece would share some of the same advantages vis-à-vis the 22mm. So the real question that you want to know is whether the 12mm T4 will also give you the same type of "fall-into-the-field feeling (at a higher power and with a smaller true field) that the 22mm T4 does. From my experience using it I would say that it usually does and I highly recommend it.

As to other eyepieces that also give you a T4 like immersive feeling I would list the 13mm T1. However, if you get a 12mm T4 (which is better in my opinion) then there is no need to get the 13. The 20mm T2 also gives you the sensation of looking through an incredibly wide field. However, I believe the 22mm T4 is even better and if you've already got that then I would not recommend getting the 20mm in addition to it.

Lastly, if you have not done so already, I suggest that you take a look through a 31mm T5. Between its incredibly wide (35% wider than a 22mm T4) true field and its much longer than average eye relief (for a Nagler) it can also (at times) give a fall-into-the-field feeling. However, I agree that three eyepieces in the T4 series are a little better and comprise a class of their own.

The 31mm I once had I let go because the sky background that I got from it (because of its lower power and larger exit pupil) was too bright for my liking. I still have a 22mm T4 and it is my go to low power eyepiece (when I'm viewing in mono mode). I've replaced my 17mm T4 and 12mm T4s with pairs with 16mm T5 and 11 T6s respectively. The T4s have their advantages to be sure, but the 16mm T5s and 11mm T6s can be used in both monoview and binoview modes and since I now do a large percentage of my viewing in binoview mode it made more sense for me to just replace my 17mm & 12mm T4s with pairs of 16mm T5s and 11mm T6s. I will say that I still kind of miss having a 12mm T4. However, given how nice the 11mm T6 is I can’t come up with a strong enough of a rationalization for why I should get another 12mm T4 in addition to my pair of 11mm T6s.

John Finnan
Posted 08/05/2006 10:53PM #3
Hello Richard. Lots of good advice that you're getting.
I just recently added a 12mm T4 to my collection,
and liked it so much, I just bought a 17mm. grin
Haven't felt the urge to get the 22mm yet.
My longer focal lengths are T5's (20, 26, 31mm).
I had held off on getting the 12mm, since I still carry
the Meade 14mm and 8.8mm UWA's in my case,
though they've been getting a lot less use. wink
Once I go to more power than the 12mm provides(150x),
I generally go for the T6's (11, 9, 7, 5mm),
unless I'm doing planetary viewing.
Anyway, I would definitely recommend the 12mm T4!