This is a somewhat smaller, lighter and more powerful version of the celebrated 31 Nagler Type 5. It weighs about 1.6 lbs and has a field stop diameter of 35mm.
Reviewed by 2 customers
I have the Nagler 31mm Type 5 and love it so much that I also bought the Nagler 26mm Type 5. It turns out the 26T5 is actually better in my scope than the wonderful 31T5. The slight increase in magnification of the 26T5 gives a slightly darker background than that of the 31T5. The true field is very slightly less than that of the 31T5. In my 5.5" F7 APO refractor star field is sharp pin-point all the way to the edge of the field. The eye relief is just right not too long and not short at all. The 26T5 is a large and heavy eyepiece and for some dob balancing may be a problem. If super wide and well corrected field is what you after the 26T5 definitely will satisfy you.
I purchased the 26 Nagler as a wide field eyepiece for my 15â€ Obsession f/4.5. Because of the fast focal ratio my telescope is very unforgiving on eyepieces. Without going into incredible detail, the Nagler was very well corrected which made for less comma off axis, it yielded a 5.78mm exit pupil, was para focal to the 17mm Nagler T5, has a TFOV of 1.17 degrees, and had good eye relief. The Televue 26mm Nagler T5 eyepiece is by far the best possible choice for any telescope in the f/4.5 range for wide field viewing. It allowed me to see dust lanes in the Andromeda (M31) galaxy, spiral structure in M51, and great detail in both M81 and M82 at the same time. I would highly recommend it to anyone serious about amature astronomy.