Quote:
Originally Posted by casstony
Even if the eye can't see more than 70 degrees, the peripheral field of view helps to frame a DSO or show it's full extent, or helps to track a planet with a dob.
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Peripheral vision! Yes!
Quote:
Originally Posted by bratislav
I think you should speak only for yourself. Human eyes can certainly see more than 70 degrees. Why do you think NASA spent all that money and research time to develop well over 100 degree eyepieces for Lunar landing simulators ?
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Our peripheral vision I believe is a little over 180degrees. I have never said that ultra wides don't work. Man, I will never forget the view of Eta Carina using Eric's ES 14mm 100deg with an NPB filter in my 17.5" dob!!! If we talk about the effective visual range of our eyes, that's a different matter I'll argue.
Our effective averted vision is limited to a narrow band around our central vision. If you think about the productive viewing that you actually do, it really limited to that area around our central vision, and therefore the 68-72 degree range. Peripheral vision is not what I'm talking about, purely
effective productive visual range.
There is also the critical "sweet spot" that your eye needs to be placed in to use ALL of these ultra wide EPs. To far out or in of this spot and aberrations such as kidney beaning comes into play. If you are happy to deal with this, that is absolutely fine. Of course it is a very subjective matter. I find this sweet spot too limiting, for me. I just can't tolerate the constant relocation of my head to avoid these aberrations. With my passion for sketching I can do hundreds of head movements from EP to paper and back over a three hour period. The much more forgiving situation that sub 72 degree EPs offer me make them as wide as I go with EPs in my collection.
Explore Scientic 68's, Delos, Panoptics, LVW's, Hyperions. These are what you'll find suit
me, 
.