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Old 27-03-2018, 10:58 AM
dpastern (Dave Pastern)
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dpastern is offline
 
Join Date: Jan 2009
Location: Brisbane
Posts: 2,874
Quote:
Originally Posted by astro744 View Post
I think some people are more sensitive to eye placement on certain eyepieces than others. I have all three of the T4 Naglers and find them very easy to use and prefer their 82 degree field to that of the T6 series. The only Nagler I have ever had eye placement problems with is the original 13mm (now known as Type 1). I still like the 13mm Original very much and prefer it over the T6 for the field simply appears wider to me as it does too in the 12mm T4. In fact the 12mm T4 has almost the same true field as the 13mm T6 as there is only 0.5mm difference in field stop diameter.

The phenomenon is known as spherical aberration of the exit pupil. The Type 2 Nagler onwards had this corrected for most part. I don't own any T2 Naglers but have looked through the 12mm and 16mm many times a long time ago and cannot remember any eye placement issues with these.

Everyone can only look through their own eyes and what one person has a problem with the other may not and vice versa. The best solution for anyone contemplating getting any new eyepiece is to try one perhaps even in their own telescope at a star party or if that is not possible then at least at the store that sells them before they buy anything.

Whatever you choose, enjoy!
yes, I'd definitely recommend trying before buying. If anyone wants to try my 12mm t4 in Brisbane, I'm happy to meet up for a night of observing :-)

I have near sightedness and mild astigmatism in my left eye, and presbyopia in my right, but I use my right eye for observing, so I don't think the issues with the t4 are down to my eyes. I've tried moving the eye back and forth away from the eyepiece without any real luck. When I can view things, the eyepiece is very sharp with neutral colours. I just get so much kidney bean effect from it...I suspect my eyes don't like UWA eyepieces as I had a few minor issues with a cheapie Andrews 30mm UWA years ago as well. The aforementioned TAL 24mm (80 degrees AFOV) is easily better with eye placement for me, when compared to the t4 nagler or andrews eyepieces. ymmv.

With that said, many users have disliked the 12mm t4 (and also the 22mm for the same reasons). I'm not making it up. A bit of research will show this. the 13mm t6 is probably a better bet in all honesty.

I like TV eyepieces btw (I have a 30mm plossl, and also a 3.5mm delos, the latter of which hasn't been used yet).
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