120 deg FOV? Is there a name for widefield eyepiece addiction?

[trent_julie]

I thought I would challenge the great minds of the forum here and ask the question what comes after 100 deg FOV?
Call me demanding, call me silly because these eyepieces already exist.

Would it be practicable to have an eyepiece with a FOV more than 100 degrees?

Does physics allow this to happen in the 2 inch realm?

Will these larger FOV eyepieces came with a neck brace included?

Or would these eyepieces be limited by aperture?

Does anybody care, or do have to ring up DR Karl?

Anyhow.....if the name doesn't exist already I propose the name fovamania for the addition of wide field eyepieces which I'm clearly a sufferer of...... just ask my regular supplier of eyepieces........... :)

[Wavytone]

... the Koehler eyepiece is a 120 degree FoV design, with 11 elements, it's not the only one; there are other military designs.

The larger the FoV the more elements and surfaces internally, ie light loss and scattering will be high

[trent_julie]

wow, i had no idea, so i guess for now we are at the end of our technology capabilities as far as astro is concerned for now

thanks for the answer

[casstony]

Here's a page showing different eyepiece designs that you might find interesting: http://members.shaw.ca/quadibloc/science/opt04.htm

With modern coatings I think the number of eyepiece elements isn't a problem, but getting an 11 element eyepiece to perform well would be costly. My type 4 nagler has coatings that are noticeably higher transmission than my type 1 nagler, and the latest Televue eyepieces are reputably better again. (Qualification: you're not challenging a great mind here :))

[Starkler]

Im waiting for the truly immersive experience of being able to put your whole head inside the fov :lol:

[JD2439975]

Look out he's going for the 35mm, 120 degree EP! :eyepop:

Stay clear of the forklift, add 5 kg to the back of the scope and another 10 kg to the arm...what do you mean "the EQ6 won't take it" she can do anything! :lol:

[Don Pensack]

With the very best coatings possible, an 11-element eyepiece, even with all separate lenses (unlikely), or 22 air-to-glass surfaces, transmission could be as high as 97-98%, so coating technology has already made this possible (think high-end camera lenses).
But the one thing you can't escape is wavefront degradation. Every glass surface has a particular peak-to-valley wavefront accuracy, and the errors could be additive (not likely--there should be some error cancellations), so the surfaces have to be more accurate the larger the number of elements.
That's why eyepieces with high element counts that also happen to be sharp and show little or no light scatter are expensive. It takes a much longer period of time to make them. Add more materials, better coatings and slow production, and it's not too surprising they cost more.
And if the design of the Kohler were improved to the best modern astronomical standards, I shudder to think of the costs!

[rider]

Is there a name for widefield eyepiece addiction?

Yes, - its called "divorce"