Telescope Reviews: Zhitong 11mm 80° Wide Angle 1.25” Eyepiece Review

I bought this EP as well and tested it on my f/10 SCT and f/6 refractor at Mt. Pinos last night and it was at least as good on the SCT as described in the Mak and only slightly worse on the f/6. The odd thing, in my scopes, that seems to work for this particular EP is the way it deals with curvature of field (not pincushion distortion, but out of focus at the edge of the FOV) is that it seems to correct this error in my scopes while most of my other cheapie EPs seem to exacerbate it.

For instance: my 20mm 65° GSO SV and 30mm 80° 1rpd have pretty bad curvature of field (IMO) in both my scopes. If I focus on stars at the center of the FOV, the edges are not sharp at all. I can refocus at the edges to get a much sharper image (but with some residual astigmatism). The dominant edge-of-field aberration is definitely the curvature of field which overwhelms the astigmatism present in these 2 EPs.

With the 11mm 80° Zhitong, there is astigmatism present at the edge of the FOV but little to no curvature of field, thus giving a nicer total FOV than either my 30mm 1rpd or 20mm GSO SV (which are still EPs I like and use every time I'm at the scope). This means that the 11mm will be added to the standard kit that comes out even for quickie backyard viewing sessions.

Complaints about the EP:

1) Short ER, which wouldn't be so bad except for:
2) Stupid rubber eyecup doesn't fold down and is *very* stiff, thus effectively preventing you from seeing the entire FOV. I switched the eyecup from my KnightOwl/Synta WA 6mm which works very well and this problem is solved.
3) Field stop is very fuzzy - worst of all my EPs and many of those are cheapies.
4) Dust in my EP is visible, which also means that the apparent focus point is near one of the elements' surfaces. I will open up the EP and try to clean it with the instructions many have made here on CN and maybe I can figure out what's up with the fuzzy field stop.

Nevertheless, for $45 it's a good deal. I really need to get the EP out again in the f/6 as I was not expecting it to be useable at all in that scope. As I stated, it turned out to do quite well, perhaps due to a "canceling out/correcting" of field curvature that I see in most other cheap EPs in my scopes.

However, Don is right about the Speers WALERs, if you can swing the ~$130 these are absolutely wonderful EPs which give better performance, esp. edge correction, than this EP. My S-W 5-8mm is clearly the best EP I own.

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8" LX90, StarBlast 6", 100mm f/6 achro, 60mm f/5.8 achro, 60mm f/11.7 achro, 10x50s, 15x70s