2' EP's

[Varangian (John)]

Originally Posted by Suzy

I echo what Mental said about the Hyperions performing poorly in fast scopes. I bought a 5mm for my 10" dob and it showed bad vignetting. It was quite distracting and rendered the field of view far smaller than the 65 deg. (or is 68, I forget). So back it went.
Being a 5mm, I was happy to try them as I didn't want to spend lots of dollars for a focal length that would get little use. So now it's back to spending the big dollars to add another Pentax XW5mm to my collection. Adorama in the U.S. have got them on special for only $279 (+ about $50 shipping) at the moment- that's the cheapest I've seen them todate. Opt are still selling them at $360 plus shipping!
The Vixen LVW and Pentax XW's are fantastic eyepieces- 20mm eye relief, large field of view and very very comfortable! They perform beautifully in fast scopes both in edge performance, sharpness and contrast. There's nothing not to like and worth every single penny!
I've avoided the Explore Scientifics purely because of the lack of eye relief which is important to me, otherwise I hear great things about them.

Interesting, I have a 4.7 10" Dob and Hyperions/Stratus' and I just don't see this issue to the extent that is a problem. Maybe my standards are much loweror I haven't looked through sufficient premium eps

[Chooka03]

Since this post is on 2" EP's, I'll ask my question here....

I'd like to get just 1 2" eyepiece. What would be the best size to get if you only wanted to own 1 2" EP ? A general all rounder.

For me personally, I'd probably use it for open clusters not planets or single stars. I'm guessing people will suggest 20 - 32mm??

I currently own a 1.25" 20mm ep and a 10mm ep.

Thanks for the feedback!

[Gem (Grant)]

If you are only getting one 2" EP - I would get something that has a FOV that is impossible in a 1.25". For example, the max FOV for a 1.25" is a 24mm Panoptic or a 32mm Plossl. So get something that is larger than that....

[Wavytone]

Long eye-relief eyepieces listed below.

If you wear specs the Vixen LV and LVW series both have lot of eye-relief across the whole range and also have a nice soft rubber eyecup that won't scratch spec's (if you wear them to observe, as I do). Some of the others listed below don't, so if this matters to you it is advisable to check.

1. The original Vixen LV series had 20mm eye relief, focal lengths from 2.5 to 25mm were in 1.25" barrels, then two very big ones - 30mm and 50mm both in 2" barrels. These went out of production long ago and very hard to find secondhand but see NLV below. Excellent eyepieces though outgunned by the ultra-wides that seem to be more popular.

Vixen also made a very nice zoom eyepiece based on the LV design in a 1.25" barrel with similar long eye relief, a bargain if you find one.

2. The Vixen LVW series have 20mm eye relief, and are still available; from 5mm to 22mm in dual 2"/1.25" barrel; then 30mm and 42 mm in 2" barrels.

3. Vixens NLV series, 1.25" barrels, optically the same as the LV series upto 25mm focal length in a different barrel style with a hard plastic eyecup, and currently available. The downside is the big fat fugly eyecups.

3. Televue Radian - 20mm eyerelief.

4. Televue Panoptic - eye relief ranges from a useable 13mm to 27mm depending on the eyepiece focal length. The 19mm and 24mm are in 1.25" barrels, the rest 2".

5. Televue Delos - 20mm eyerelief (all). 3.5-17mm focal lengths, all in 1.25" barrels.

6. Pentax XF - 18mm eyerelief, 1.25" barrels.

7. Pentax XW - 20mm eyerelief, dual 2"/1.25" barrels.

Note the Pentax XO series have very short eye relief.

8. Baader Hyperion range. A somewhat inferior copy of the Vixen LVW series, which doesn't perform so well in fast scopes.

9. The Edmund RKE 21mm and 28mm deserve a mention; both with long eye relief though the 21mm has a raised metal ring around the eye lens that basically defeats the whole point of eye relief, and is a menace if you wear specs (they will get scratched).

There are some other obsolete ones too, notably Vixen LV's rebadged by Celestron and others. Then there are the cheap chinese clones... I don't have consistent specifications for these, though i am sure some will be reasonably OK as budget eyepieces.

[skytry (Peter)]

hi Wavytone,
thank you,
your entry has enlightened, as too the different eyepieces available, and their ID for eye relief,
I shall be in the near future take on board your advice,

regards,
Peter.

[ZeroID (Brent)]

Originally Posted by Gem

If you are only getting one 2" EP - I would get something that has a FOV that is impossible in a 1.25". For example, the max FOV for a 1.25" is a 24mm Panoptic or a 32mm Plossl. So get something that is larger than that....

I got a 32mm Kellner mainly because it was on sale and I wanted to see what difference it made. Gives lovely widefeild views, almost TV screen like and great for scanning around but quite heavy and the FOV is only the same as my GSO 20mm SV's which was about the same price. The 10" scope limit on 2" is 34 mm from what I researched.

[MortonH]

Originally Posted by Chooka03

Since this post is on 2" EP's, I'll ask my question here....

I'd like to get just 1 2" eyepiece. What would be the best size to get if you only wanted to own 1 2" EP ? A general all rounder.

For me personally, I'd probably use it for open clusters not planets or single stars. I'm guessing people will suggest 20 - 32mm??

I currently own a 1.25" 20mm ep and a 10mm ep.

Thanks for the feedback!

What scope are you planning to use it with?

[Wavytone]

Originally Posted by Chooka03

I'd like to get just 1 2" eyepiece. What would be the best size to get if you only wanted to own 1 2" EP ?

Easy - I'd buy something that gives you a field of view that you CANNOT buy in a 1.25" eyepiece, in order to take advantage of the extra field of view available in a bigger barrel.

What that means is look for eyepieces with a field stop larger than about 22 mm, and means focal lengths longer than 20mm depending on the focal length.

Candidates:
ES 100 degree eyepiece, 20mm
ES 82 degree eyepiece, 18/24/30mm