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2" Eyepiece advice please

Helen

By Helen
in Discussions - Eyepieces

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Helen

Helen

Posted
Posted

Hi again,

Some more help please... I've got a Megrez 90 and would like to benefit from those WIDE views. I've got a WO 16mm UWAN and its great - double cluster and Plaeides are amazing! (I've also got the Meade Plossl Anniversary set). I'm now looking at buying a first 2" widefield eyepiece. What would you recommend with a budget of say £100? (can't justify too much money as I've just bought the 3-6 Nagler from Steve!)

Thanks Guys

Helen

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moondog

moondog

Posted
Posted

I was just about to post the same recommendation Steve !

I have this EP. Although it's good in my Revelation 80ED it's more impressive in the longer focal length TAL.

Practical Astronomer said it was just about unbeatable at the price. They still had the same slight concerns I had with use with a short focal length scope. Don't know what FR the Megrez is but the Revelation is F 6.8.

I don't think you'll beat the Moonfish with anything else for your budget.

MD

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Ambermile

Ambermile

Posted
Posted

I have a little 1.25" Antares W70, as good as you'll get and that's used on the 22" f/4.8 - really. It's a bit embarrassing dropping it in the focuser but it really is a nice EP and the FOV is as good as any 2" I have.

Point is - don't get hung up on 2" being "better" than 1.25"

Arthur

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Helen

Helen

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Thanks so far everyone. I'd seen the Moonfish ones and wondered. My scope is f6.9 would that be too short for the 30mm Moonfish?

On the Antares Arthur, what size have you got? Like CC I'm a little confused.. I thought that if I went above 28mm then I would benefit from a 2" eyepiece as in a 1.25" I'd be restricted by the field stop - is that right??

I've also been looking secondhand too... anyone know what the wide scan III eyepieces are like as I've seen a 30mm for £85?

Thanks

Helen

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bern

bern

Posted
Posted

Helen & CC, you only benefit from 2" eyepieces when the linear field of view is restricted by the ID of the 1.25" eyepiece barrel.

This happens with Plossl type eyepieces when the focal length is greater than about 32mm to 35mm, with wide field designs it's lower.

bern

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russ

russ

Posted
Posted

The Moonfish does appear to be the best value Upto £100. Although those WO UWAN's are better, shame they are so pricey.

If you could find the extra, the Burgess Optical TMB Paragon 40 is currently supposed to be the best widefield 2" eyepiece bar none (that includes better than the TeleVue line up). And it's a bargain at £169. Worth every penny as its performs in all scopes and is pin point sharp edge to edge.

Russ

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John

John

Posted
Posted

You could also look out for a 30mm KK Wide Scan III - these have an 84 degree field which is just about the widest possible - even in the 2 inch format. There was one going for £85 on Astro Buy & Sell a little while ago - it may still be available.

I can recommend these as I use the 20mm, 16mm and 13mm 1.25 inch versions which work very well in my f7.5 ED100 although I don't think they are worth their new cost (around £200 I think) as you are almost into Nagler terratory then. I have compared the 20mm directly with my 24mm Panoptic and it comes out very well in my medium FL scopes - so much so I'm currely debating whether I can hold on to my Panoptic - it's just not seeing much use.

John,

North Somerset

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FLO

FLO

Posted
Posted

This might help :rolleyes:

The 2" Meade Series 5000 32mm is included cuz I like it. It hasn't got the huge FOV of the Moonfish but it is a lovely eyepiece and almost its entire 60 degrees FOV is usable. A little over budget but not by much, after some discount...

The difference between the 16mm UWAN and the Moonfish FOV is remarkeable!

post-12699-133877323693_thumb.jpg

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GordonCopestake

GordonCopestake

Posted
Posted

OK, so what is the point of 2" eyepieces then? I'd assumed that they gave a wider FOV just by being, well, wider.

It's very interesting that the smaller (cheaper) EPs can be as good as their expensive cousins.

Captain Chaos

2" eyepieces are only useful if the field stop is greater than the barrel they sit in. The 24mm panoptic and the 15mm T6 nagler both have the maximum fieldstop for a 1.25" eyepiece. For a 50 degree eyepiece (plossl) the 32mm eyepiece is the maximum focal length the 1.25" format will support without vignetting. For longer focal lengths a 2" eyepiece is needed. A 2" format 32mm or shorter eyepiece is a waste as there is no vignetting in a 1.25" barrel. The exception to the rule is eyepieces like the hyperion/status where they supply the barrel in a duel 2"/1.25" barrel simply for convienence

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themos

themos

Posted
Posted

Is it ok if we revive this topic?

As I have a 300P Skyliner (12", f/5) I am considering a widefield 2" eyepiece.

Is the Moonfish 30mm Ultrawide 80° 2" Eyepiece - Enhanced still the best in class at £69?

Any experiences with the TeleVue WideField 32mm or the TeleVue Panoptic 35mm or the Pentax SMC XL 40mm?

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Whippy

Whippy

Posted
Posted

Is it ok if we revive this topic?

As I have a 300P Skyliner (12", f/5) I am considering a widefield 2" eyepiece.

Is the Moonfish 30mm Ultrawide 80° 2" Eyepiece - Enhanced still the best in class at £69?

Any experiences with the TeleVue WideField 32mm or the TeleVue Panoptic 35mm or the Pentax SMC XL 40mm?

As it goes, I'd be interested too as hopefully I should be in the market for a wide field EP to go in my f7 'frac and f5 reflector soon. Those moonfishes look interesting, does anyone actually have a recommendation on a focal length if you was going to buy just one EP (for now)?.

Tony..

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Albireo380

Albireo380

Posted
Posted

Thanks so far everyone. I'd seen the Moonfish ones and wondered. My scope is f6.9 would that be too short for the 30mm Moonfish?

On the Antares Arthur, what size have you got? Like CC I'm a little confused.. I thought that if I went above 28mm then I would benefit from a 2" eyepiece as in a 1.25" I'd be restricted by the field stop - is that right??

I've also been looking secondhand too... anyone know what the wide scan III eyepieces are like as I've seen a 30mm for £85?

Thanks

Helen

You could also look out for a 30mm KK Wide Scan III - these have an 84 degree field which is just about the widest possible - even in the 2 inch format. There was one going for £85 on Astro Buy & Sell a little while ago - it may still be available.

I can recommend these as I use the 20mm, 16mm and 13mm 1.25 inch versions which work very well in my f7.5 ED100 although I don't think they are worth their new cost (around £200 I think) as you are almost into Nagler terratory then. I have compared the 20mm directly with my 24mm Panoptic and it comes out very well in my medium FL scopes - so much so I'm currely debating whether I can hold on to my Panoptic - it's just not seeing much use.

John,

North Somerset

I have a 30mm KK widescan III and use it on both a 10" Skyliner and WO Megrez II SD. It performs very well on the big Dob, but does show a little abberation in the outer 10% of the FOV with the Megrez. The Dob is f5 and the Megrez is f6, so I am not sure why it shows any abberation. Having said that, the views with it through either 'scope are great - it is breathtaking when used on the big Dob - x42 magnification and 2 degrees tFOV - real spaceship porthole views.

If you can pick one up at £85, secondhand - go for it.

Tom

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dph1nm

dph1nm

Posted
Posted

So just to confuse the issue further, Moonfish (and others) also do a Wide Scan 32mm 70deg AFOV 2" eyepiece, at much the same price at the 30mm 70deg SuperView. So what on earth is the difference between all these?

Also, in Newtonians, with such wide fields isn't there an issue with vignetting due to the diagonal size?

NIgelM

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daz

daz

Posted
Posted

Nigel

If the AFOV is the same, then the difference between 32 and 30mm is negligible - all depends on personal preference. Wide Scan, Super View - just names!

As for the newtonians, you don't use a diagonal so its not vignetting that the issue - its the f ratio of the scope. The faster the scope (lower the f ration) the more steeply the light cone is angled and the harder it is for the EP to bring the light to parallel. What you end up with is 'kidney beans' on the outer edges of the field of view.

The worse the EP performs, the worse the beaning, and the higher percentage of the FOV it covers.

The Moonfish do a pretty good job - had one myself when I had an 8" f/5

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The Warthog

The Warthog

Posted
Posted

Nigel

As for the newtonians, you don't use a diagonal so its not vignetting that the issue - its the f ratio of the scope.

I suspect Nigel is referring to the diagonal secondary mirror...

You would have to go a long way to convince me that vignetting due to the 1.25" tube really occurs. I can see you might lose light, but even my lowest power in my refractor is only covering an area of sky 1.4 degrees in diameter. That is about the angle that a minute hand moves in 15 seconds. Surely the light path is going to clear that tube without loss of field, but with only loss of light (aperture effect) to worry about. Or is that what I've been missing?

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