Very happy with this eyepiece. Its my favorite for examining discrete deep sky objects, with excellent contrast and sharpness to the edge of the field. I find that the Instajust eyeguard allows for individualized framing of the view and is easy to use, although there is some range of opinion about it. Very comfortable eye relief. Highly recommended!

Fabuluous contrast and apparent sharpness, but does not provide a relaxed comfortable view. Black out will be a problem for some.

just when i thought it couldnt get any better than the 12mm t4 nagler, i purchased the 17mm t4 & all i can say is unbelievable!! pinpoint stars across the entire 82 degree afov!! wow !! i really like the instajust eyeguard, it takes a little getting used to but once you do nothing else compares!!

After year of using this eyepiece , I find that I most frequently use it while viewing galaxies and trying to track down small planetary nebulae. Thanks to this fine EP , I was able to complete the Messier list in short order. By coupling a wide FOV with adequate magnification , it has given me the best views I have had of the Leo Triplets and the M81 , M82 galaxy pair. The f.l. of the EP yields enough magnification in my TOA 130 and my TMB 175 to effectively enhance contrast by darkening the field while maintaining a wide enough field to view either large objocts or groups of seperated galaxies. I rated this EP as a 9 stars in comparison to my Panoptic 35 , which I rated 10 stars ; this is based on viewing comfort. I find I have to work a bit to avoid an occasional blackout with the Nagler , and not with the Panoptic.

I use this eyepiece with my 10SN f/4 and I have to say that it feels as if you look from a spacecraft window!! Amazing wide field views, high contrast, sharp image. A must have for anyone who loves wide field views from a large aperture scope.