One wide FOV EP or bino-ing w/ normal EPs?

[GUS]

Hi everyone, any thoughts on which is preferable? One wide FOV eyepiece or binoviewing with two eyepieces in the normal field of view range?

Thanks, cheers!

[ronin]

One of the "problems" with a wide angle eyepiece is that your eye still limits what is visible. What is found is that you may have an 82 field from the eyepiece but the eye accepts 60 degrees so the outer 10 degrees around the outside is kind of out of view. To see this bit you have to move you head or eye and kind of look over to the side.

What a wide FoV eyepiece does is remove from view an "hard" edges, so you have sky edge to edge when you look down the center, hence the use of the term "immersive". Often it is this effect that people like.

It is a little strange that when talking of the optics involved that people tend to forget to final item = your eyeball.

Bino-viewing is likely to give wide views anyway and may be more comfortable, although it is generally not a case of switch from one to the other, other things get altered so it is not quite a simple 1:1 correlation.

Do you have a binoviewer ? Basically can the scope operate straight off with the unit in place, from previous posts it is not always easy.

I would suggest just sticking with a single eyepiece, wide or otherwise. It seems to be the proven way of doing it all.

[Moonshane]

What are you observing? I use binoviewers with plossls for solar system and double stars only as I find the view better through mono for everything faint.

The detail to my eyes is much enhanced, and the experience more relaxing with binoviewers of the objects I use them for. However, if you are asking about what's best for general observing of all objects, I'd suggest single eyepieces, whether wide field or not. I personally prefer the field up to about 70 degrees afov for mono viewing.

[Stu]

@ronin, for reference, which binoviewers have you used in your scopes?

My question to the OP would be 'which targets are you interested in?'

In my experience, binoviewers work very well for mid and high power targets. I tend to use smaller refractors a lot of the time (100mm) and the problem you find is that at high powers you get small exit pupils and as a result you do see any floaters in your eyes which can be distracting. Using binoviewers can alleviate this to a large extent.

Your brain and eyes are very clever, and work together to build an illusion of a 3D image, although it is just an illusion.

Whether or not you get on with binoviewers is a very personal thing. For me they work beautifully for white light and Ha solar observing, aswell as lunar, but strangely they do not help me for planetary observing, I see more detail with a single eyepiece despite the floaters I see.

I have yet to spend much time with mine on low power targets, but from the limited time I have had, the results are pretty good. The challenge with binoviewers is often getting low enough powers. They take up a lot of backfocus, so you generally need to use a Barlow to reach focus which pushes the mag up. The scope needs to be designed with binoviewers in mind to achieve low powers.

In summary, for me it is binoviewers for solar and lunar, single eyepieces for low power. A nice 31mm Nagler in a wide field refractor is hard to beat on the Double Cluster, Veil etc.

I would encourage you to try them first, or at least buy used so you don't lose much if you choose to sell.

[Louis D]

9 hours ago, GUS said:

Hi everyone, any thoughts on which is preferable? One wide FOV eyepiece or binoviewing with two eyepieces in the normal field of view range?

Thanks, cheers!

What do you mean by wide FOV eyepiece?  You're never going to get two 41mm Panoptics, 31mm Naglers, or 21mm Ethos to work together in a binoviewer or binoscope because you can't get them close enough together due to their width to see both images with your eyes at the same time.  I say get both.  Get some good widest field eyepieces for lower power views, and an entry level binoviewer with simple eyepiece pairs for higher power views.

[GUS]

Thanks guys,

Ronin, it's amazing that you say the eye only sees up to 60° without looking from the side, and to think there's even a 120° ep out there!: 

https://telescopes.net/store/eyepieces/category/eyepieces-by-field-of-view/100-120-fov/explore-scientific-9mm-120-argon-purged-waterproof-eyepiece-2.html

Is all that extra real estate lost because the 'horizon' for the human eye ends at 70 or 80° and even for that you have to tilt your head? Good to read a description of what the immersive effect specifically entails, namely no borders, not even in the far away outer edges.

Moonshane, I don't have a binoviewer yet but plan on buying the Orion, especially since I've read positive reviews and the fact that it comes with a 2x barlow. On that point, would it make a world of difference if that barlow were a 2x powermate instead of the one included with the bino, all else being equal? Any insight on this anyone?

Answering your question I want to look at the moon and planets but mainly at the sun, in white light and Ha, although a sunspot at high mag will be moving out of view much faster than a whole disc view, and if you're using a manual alt azimuth mount, you're going to have to turn those knobs like there's no tomorrow I assume. If you're doing Ha it doesn't matter so much since you'd still be looking at something - fire! But if you're doing white light and all you have is a sunspot to look at in a sea of featureless white, then it'd be more pressing to not lose sight of that sacred sunspot. Why do you prefer up to about 70° degrees afov for mono viewing? ¿For the same reason Ronin says, that the eye can't see much more beyond 70- tish°?

It's great that binoviewing and high power go well together, and although more challenging, low power can also be achieved (thanks Stu). I get a nice full disc view occupying the bulk of the fov with my Celestron 8-24 zoom ep at 24mm and 40° afov (in mono). Anything below that and the Ha disc quickly degrades into the universe of dimness and blurryness, mostly the latter. So I guess I could binoview on the cheap with a pair of these for full disc and cough up a few more zeros for some top of the line optics for high power viewing. So Louis D, thanks for the advice but 'simple' ep's don't cut it for high power. Funny to think that for Ha just about any singlet objective lens that isn't plastic is as good as a doublet (or triplet even?) APO, but when that same extreme narrowband monocolor light stream hits the ep, then it suddenly really matters what ep it's traversing. Well, that goes to show that the laws of magnification also apply to monocolor.

Has anybody seen CA when looking at white light, or is it, like in Ha, also absent? Or mostly absent, even though it has all the colors (which might not all come to focus at the same sharp point)? I've only looked at white light through my sv60eds which is an APO, so there's none there, but my ep isn't (though it's fully multi-coated mind you), and none either with my 10x70 binoculars, which aren't anything to die for, so I wonder.

Stu, there's hardly any secondary market here; I've never found used binoviewers advertised, mostly only whole telescope and tripod setups. Just about any accessory you need you have to import it. Add postage, customs duties, S&H,  freight forwarder or import agency profit... and you end up paying about one and a half times the sticker price.