13 replies to this topic

[Tubuskahusk]

So what are the differences between the 20mm type 2 and 20mm type 5 Nagler. Also if you look through them side by side in the same exact scope could, you tell any differences?

[jrmacl]

So what are the differences between the 20mm type 2 and 20mm type 5 Nagler. Also if you look through them side by side in the same exact scope could, you tell any differences?

here's a start:

 

https://www.cloudyni...pe-2-vs-type-5/

[Tubuskahusk]

The scopes I would use it in are
10 1200 f5 dob
12 f4.5 dob
16 f4.5 dob
I do use a Paracorr type 2 part of the time.

[Tubuskahusk]

Thank you for the link jrmacl. It has given me lots of very useful information.

[jrmacl]

Thank you for the link jrmacl. It has given me lots of very useful information.

You're welcome. Having read CN for decades, I seen some who just love their T2's and others can't see a difference and others who love their T2 but switched to the T5 for newer coating or lighter weight. I think I may have even seen posts where people preferred the heavier T2 because their other ep's were also heavy and they didn't have to rebalance their scopes.

[Astro-Master]

I have the 20mm T2 Nagler, and years ago compared it to the 20mm T5 Nagler. 

 

The T2 has better edge correction, but is heavy, 2.2lbs. The T5 is lighter and has better coatings for a brighter image.

[PKDfan]

I have the 20mm T2 Nagler, and years ago compared it to the 20mm T5 Nagler.

The T2 has better edge correction, but is heavy, 2.2lbs. The T5 is lighter and has better coatings for a brighter image.

I suspected as much Bruce but Thank You for confirming that.

Its truly an insane eyepiece and maybe someday i'll find a Type5 to compare it too but for right now i'll glee in the optical bomb that it is.

It'll sure leave a crater behind if you drop it !


CSS
Lance

[Astro-Master]

I suspected as much Bruce but Thank You for confirming that.

Its truly an insane eyepiece and maybe someday i'll find a Type5 to compare it too but for right now i'll glee in the optical bomb that it is.

It'll sure leave a crater behind if you drop it !


CSS
Lance

I got my 20mm T2 for a 25th wedding anniversary present many years ago, and it's still my favorite eyepiece to scan the Summer Milky Way with my 18" Dob. 

[TOMDEY]

The Type2 is better because it is a smoothie.    Tom

[Ernest_SPB]

I had no possibility to compare 20 mm Type 2 vs Type 5, but I have tested 16 mm Type 2 vs. Type 5.

 

Type 5 gained in the following: image quality (both in central zone and at edge), weight, dimensions and distortion...

I have tested 20 mm Type 5 and it looks like scaled version of 16 mm with the same level of aberration control.

Edited by Ernest_SPB, 29 April 2025 - 01:46 AM.

[PKDfan]

I had no possibility to compare 20 mm Type 2 vs Type 5, but I have tested 16 mm Type 2 vs. Type 5.

Type 5 gained in the following: image quality (both in central zone and at edge), weight, dimensions and distortion...
I have tested 20 mm Type 5 and it looks like scaled version of 16 mm with the same level of aberration control.

Hi Ernest !

I'd dearly love to send you my two Type2's that your bench testing would surely find better aberration control than the 16mm T2 but if they would get lost my whole optical world would simply crumble.


Let me take this moment to give you my Thanks for your marvelous site and all the hard work you do.
Your a bit of a legend and an invaluable resource that has guided my purchases and i'm sure many others.

Thank-You !!


Clear Steady Skies
Lance

[RichD]

The 20mm T2 is an older eyepiece now, with old tech coatings and slightly lower transmission values. But, it's an absolute classic with excellent image quality and a wonderful "fall into it" feeling in use. If you find one used in good condition for a fair price as I did, it can be a great buy. It's still one of my all time faves.

Just be warned it's very heavy, 1.1kg (2.3lbs). And can unbalance your set up.

Some of them are nearly 40 years old now, and were discontinued in 1999.

[John O'Hara]

I have very much enjoyed my 20 T5 for many years. However,  my astigmatism has gradually increased to  1.00 diopter and I'm beginning to notice it at the exit pupils it provides in my scopes. I'm starting to consider a longer eye relief occular for this reason, or possibly a TV Dioptrx astigmatism corrector. The 20 T2 is not listed as compatible with the Dioptrx,  while the 20 T5 is (with the adapter). However,  I'm guessing it will vignette the field). 

 

If you have astigmatism,  you might want to consider this before purchasing either of these fine eyepieces, or choose something with long enough eye relief for glasses. 

 

John

[lwbehney]

I have very much enjoyed my 20 T5 for many years. However,  my astigmatism has gradually increased to  1.00 diopter and I'm beginning to notice it at the exit pupils it provides in my scopes. I'm starting to consider a longer eye relief occular for this reason, or possibly a TV Dioptrx astigmatism corrector. The 20 T2 is not listed as compatible with the Dioptrx,  while the 20 T5 is (with the adapter). However,  I'm guessing it will vignette the field). 

 

If you have astigmatism,  you might want to consider this before purchasing either of these fine eyepieces, or choose something with long enough eye relief for glasses. 

 

John

I think astigmatism is one of the major reasons the T5 31 mm Nagler is so popular compared to the Panoptic 41 and the 55 mm Plossls. That, and the darker field which a little more magnification provides.