82 degrees vs 100 degrees???

mbaddah (Mo) · #1 19-08-2009, 12:09 AM

Was seeking the advice and opinions of those whom have experience looking through an eyepiece with 82 degree fov and 100 degree fov as I'm tossing up between a Nagler 13mm T6 and an Ethos13mm/ES14mm.

Greatly appreciate all your help guys thanks

wavelandscott (Scott) · #2 19-08-2009, 09:28 AM

How do I say this...don't look through a 100 degree eyepiece unless you are prepared to buy one.

I say the above in jest but they can become addictive...when I first moved from plossls to Naglers I though WOW!...When I first looked through a 100 degree eyepiece I said WOW Again.

For some, 100 degrees is "too much" to utilize but I really enjoyed it.

I do not yet own any Ethos or Explore Scientific eyepieces (yet) but I have looked through both...they are impressive (to me) and in an undriven Dobsonian mounted Reflector I felt they were an impressive combination. The only knock I'd put on them is the size and weight of them...they are big!

Are they "worth" the price???...I can't answer that for you.

They are not my next planned purchases...but at some point I suspect that I will own them when I next "reshuffle" my eyepiece line-up.

As always, if you can please try before you buy either at the shop or at a viewing night.

JethroB76 (Jeff) · #3 19-08-2009, 11:13 AM

They certainly gave me a 'wow' experience, but I went from 68 degree EPs to the Ethos. It is big, but not overly I don't think, and still light IMO.

One other thing a few don't like is they dont have a heap of ER, so that is something you may wish to consider - try before you buy

gts055 (Mark) · #4 19-08-2009, 12:15 PM

I am very happy with the 82 degrees in Naglers. I cant see the edge of field in 82 degree eyepieces so dont think 100 degrees would benefit me. As suggested above, maybe try before u buy. Mark

erick (Eric) · #5 19-08-2009, 12:34 PM

Call me old-fashioned, but I'm thinking of stopping at 68 deg. And I have been looking through an Ethos 13mm for some months now and have a cheapie 80 deg widefield.

Yep, it's the age-old AFOV debate - on again?

What I can say is that what I do see in the field centre of the 13mm Ethos is beautiful! Sure looks like "good glass" to me. But I'm not good enough to pick a difference from the field centre of a Panoptic - so I may stay with Pans?

mbaddah (Mo) · #6 19-08-2009, 01:26 PM

Thanks guys for all your informative feedback. It seems i'll have to trial both in the field to determine which eyepiece i'll enjoy more. I may just buy a nagler/ethos and ES to compare

erick (Eric) · #7 19-08-2009, 01:50 PM

It'll need a big truck to deliver the ES - check the size and weight!

rogerg (Roger) · #8 19-08-2009, 02:19 PM

I am not an eyepiece person but had the opportunity to have a look through an Ethos recently. I was very surprised at the wide FOV. I haven't done a direct comparison to Naglers. I'm used to using at 22mm Panoptic (68 degree FOV I think).

Looking through the Ethos I could swear I couldn't find the edge of the FOV. I had my eyeball at what felt like a 20 degree angle to the eyepiece surface and could swear I still could only see stars out the side if the eyepiece. It was like the telescope was a "tardis telescope" which on the outside looked small but on the inside was the size of a whole galaxy! It felt a bit like I was being fooled, that the sky was being projected to a larger area than it should have been. Hard to explain really.

Anyhow, I don't plan on buying one anytime soon, my 22mm Panoptic and new 7mm Nagler will do me just fine between photography stuff. Besides, the size of the Ethos put me off a bit.

Roger.

Paddy (Patrick) · #9 19-08-2009, 02:33 PM

This is more a question than a comment. I wonder if a larger field of view can come at the expense of contrast. I have in the past noted some more detail on faint galaxies with a 9mm plossl compared to a 9 mm Nagler. Does adding that extra bit of sky around an object bring in a bit more light and therefore decrease contrast? This is a question that comes to mind when I occasionally contemplate upgrading my 17mm LVW to a 17 mm Nagler IV.

Any thoughts would be appreciated.

bobson (Bob) · #10 19-08-2009, 07:37 PM

I think its more our concentration on the object being viewed in smaller FOV that brings more contrast. I have TeleVue 8mm Plossl and 17mm Nagler with 2x Barlow that gives me around 8.5mm. First with 8mm Plossl I thought I saw more contrast, but when swapped with Barlowed 17mm Nagler I saw exactly the same if not more. The only difference is that with bigger FOV you tend to look at everything there is there and not concentrate on one thing. Its harder to concentrate on particular thing when other things around it destruct you.

Something like looking at Horse neb. if you try to look at it directly first time you will not see it. But with averted vision you will, and than even looking directly at it its visible

mbaddah (Mo) · #11 19-08-2009, 11:53 PM

Well I couldn't wait any longer so I placed an order on a Explore Scientific 14mm! It was priced right in between a 13mm T6 Nagler and a 13mm Ethos

Lester · #12 20-08-2009, 07:55 AM

I have enjoyed reading this thread. Not meaning to hijack the thread; if a barlow is used with the 82 or 100 degree FOV eyepieces do you still get the same FOV, or is it reduced?

Thanks.

astro744 · #13 20-08-2009, 11:50 AM

Quote:

Originally Posted by Lester

I have enjoyed reading this thread. Not meaning to hijack the thread; if a barlow is used with the 82 or 100 degree FOV eyepieces do you still get the same FOV, or is it reduced?

Thanks.

Apparent Field of View (AFOV) is the same although some very short Barlows can cause vignetting with some eyepieces. It's usually the fault of the Barlow not the eyepiece.

True field of View (TFOV) is reduced by the amplification factor of the Barlow or Powermate. ie. 2x = half TFOV.

A Powermate re-create the light cone exactly as the eyepiece was designed to see it. Eye relief is maintaned too.

Paddy (Patrick) · #14 20-08-2009, 12:26 PM

Quote:

Originally Posted by bobson

I think its more our concentration on the object being viewed in smaller FOV that brings more contrast. I have TeleVue 8mm Plossl and 17mm Nagler with 2x Barlow that gives me around 8.5mm. First with 8mm Plossl I thought I saw more contrast, but when swapped with Barlowed 17mm Nagler I saw exactly the same if not more. The only difference is that with bigger FOV you tend to look at everything there is there and not concentrate on one thing. Its harder to concentrate on particular thing when other things around it destruct you.

Something like looking at Horse neb. if you try to look at it directly first time you will not see it. But with averted vision you will, and than even looking directly at it its visible

Very interesting!

Lester · #15 21-08-2009, 12:21 AM

Thanks Astro for your reply.

wavelandscott (Scott) · #16 21-08-2009, 10:28 AM

Quote:

Originally Posted by mbaddah

Well I couldn't wait any longer so I placed an order on a Explore Scientific 14mm! It was priced right in between a 13mm T6 Nagler and a 13mm Ethos

I look forward to reading about your experiences with your new eyepiece. Congratulations!

Reviews have been positive to date or so I've read.