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Plossl Comparison


Kohala

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First post here, very exciting.  Been cruising the forums for a couple of days though.

I have a question about what upgrading my plossl eyepieces.  Currently I am running a Nexstar 8se with the crappy basic celestron plossls.  I have read that for planetary viewing plossls are best on my slow scope.  Correct me if I am wrong.  

I am torn between the Televue Plossls, the University Optics HD Abbe Orthos Phase II, or the Baader Classic Plossl.  Does anyone have any experience on which one might have the edge?

They are all about the same price, with similar features.  I think the only difference in features I am noticing is a smaller FOV on the UO plossls.  

Any advice would be greatly appreciated.

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Hi Kohala I do not have any experience with those particular makes but the revelation/GSO plossls did very well compared to the televues and another expensive make in a review I read last night. The review is linked in a thread in the eyepiece forum somewhere.

They appear to be extremely good value for money, the only issues for me is they are not the most comfortable of EP but this may be a common trait with plossls? and the fov could do with just a little bit more.

Maybe worth a look

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I've tried all the ones you list - I've got most of them at the moment in fact !

Plossls and orthoscopics have some things in common whoever makes them and that is a 40-50 degree apparent field of view and eye relief (how close you need to get your eye to the top lens of the eyepiece) that is around 80% of the focal length of the eyepiece. As the focal lengths go below around 7mm-8mm the eye relief starts to feel "tight" and some find this uncomfortable.

With your 2000mm focal length scope, most eyepieces work well and 7-8mm will be the most magnfication you will be able to use on most nights so any of the ones you list will work very well. The Baader Classic plossl is only available in the 32mm focal length - the 18mm, 10mm and 6mm in that range are orthoscopics.

There are other eyepiece designs around though (many of them !) which could offer similar excellent performance with longer eye relief (more comfort !) and a wider field of view, if you would like that. The Baader Hyperions, for example, would work excellently with your scope and don't cost much more than Tele Vue plossls.

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I've tried all the ones you list - I've got most of them at the moment in fact !

Plossls and orthoscopics have some things in common whoever makes them and that is a 40-50 degree apparent field of view and eye relief (how close you need to get your eye to the top lens of the eyepiece) that is around 80% of the focal length of the eyepiece. As the focal lengths go below around 7mm-8mm the eye relief starts to feel "tight" and some find this uncomfortable.

With your 2000mm focal length scope, most eyepieces work well and 7-8mm will be the most magnfication you will be able to use on most nights so any of the ones you list will work very well. The Baader Classic plossl is only available in the 32mm focal length - the 18mm, 10mm and 6mm in that range are orthoscopics.

There are other eyepiece designs around though (many of them !) which could offer similar excellent performance with longer eye relief (more comfort !) and a wider field of view, if you would like that. The Baader Hyperions, for example, would work excellently with your scope and don't cost much more than Tele Vue plossls.

So, it sounds like the Hyperions would be more versatile/comfortable while still yielding similar results?  Sounds like that might be the way to go.

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The orthos, given that you wont need any really small ones might work well for you, they do offer a very sharp view albeit with a restricted field of view.  For planets thats not often too much of a disadvantage.  A long focal length scope like yours wont need any of the really tight eye relief/short F/L ones. As your US based the UO orthos would probably represent the best ortho buy for you.  I cant offer an openion on Plossls - most of the ones I owned were average - neither terribly good nor terribly bad with the exception of the Celestron 32mm which was nice and the TAL 25mm which is superb.  The others were ok but not as sharp as the orthos.  Never used a TV Plossl so cant say how well they might perform.

The Hyperions are also an option, I quite liked mine (5mm and 13mm) but ditched them in the end in favour of much more expensive glass, I also found the 5mm Hyperion suffered kidney bean and black due to it being very sensitive to eye placement.  I cant say how common that is with Hyperions - the 13mm was fine.

No one has suggested the ES 82' eyepieces in this - they may work well at shorter focal lengths for you.

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With the 8Se and if you want to stay with plossl's or similar I would go for the TV plossls.

It takes a lot to better them.

At f/10 the scope is going to be easy on just about all plossl eyepieces, actually all eyepieces in general. So you have a big selection to choose from.

The possible drawbacks are that the eye relief varies with the eyepeice focal length and I am not sure the TV are parfocal. On an 8SE this may be relevant as altering focus can be tiresome on many SCT's.

Th TV range suits the 8SE, you have the 8mm and 11mm for high mag and the 32 and 40mm for lower.

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The possible drawbacks are that the eye relief varies with the eyepeice focal length and I am not sure the TV are parfocal.

I'm under impression that you've had TV plossls since many years, are they just for collection? :grin:

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I'm under impression that you've had TV plossls since many years, are they just for collection? :grin:

I have had them for quite a number of years, I slowly collected them over time, all used, finally completed with a 32mm.

They are excellent and I like the simple design, I have the strange idea that Al Nagler had some idea what he was doiing :rolleyes:

I did thank him at Astrofest one year. :grin:

The one thing they do not have is the immediate impact of other eyepiece designs, very understated.

I completed the collection just before TV upped the prices so I suspect I could make a profit on them all now.

I was a bit reluctant to use them at public events, fingers and getting lost, and I found the BST Explorers at that time, so I bought 2.

Lent them to a friend and had a fight to get them back off him.

The BST's were good and at that time £38 (maybe £36) each, I bought the set eventually and they now tend to be the ones I use.

I have one and a half sets of BST's and actually 2 sets of TV plossls :eek: :eek: . The 2 sets is a slightly insane tale.

So they are my main items, have others around but they do the majority of the work, depending on what the work is.

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I suppose on a newonian and a refractor the parfocalness is minimal.

I have a ETX Mak and to adjust the focus is in simple terms a nightmare, what is a second in time on a "normal" focuser is at least five and likely double on one of these.

So the more parfocal they are the better.

The thing is many people have Mak's or SCT's so, to my thinking, it is relevant.

The OP said 8SE so possibly relevant to them.

The TV's were used on 2 refractors, Megrez 90 mainly, and that is a simple half turn of an easily accessible knob. So I never really bothered to consider the parfocal aspect. Also like many a different eyepiece means I automatically "adjust" focus anyway. I also wear glasses and oscillate between keeping them on and taking them off. Wear glasses to find eyepiece, drop in scope, focus, take glasses off, refocus.In effect I find I adjust focus so often it is close to irrelevant to me. Unless I have the Mak out.

Being parfocal may be a little applicable to a dobssonian, less adjustment and so things remain in view easier.

Say 30mm plossl to find something (M1), then switch to am 8mm to see the detail if during the refocus you lose the target it is back to the 30mm again to relocate. So the less refocusing the better it would seem.

The other thing is I seem to like eyepieces in sets, and often now a set is parfocal(ish).

The tale of 2 sets of TV plossals is just odd.

The worst aspect is I have ended up with 2 sets + an extra 25mm (3 of those :eek: :eek: :eek: ). Not actually sure how I managed 3 of that one, honestly cannot recall buying it.

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"I suppose on a newonian and a refractor the parfocalness is minimal."  Hi Ronin, no, the benefit is the same on all types of telescopes. Funnily enough, this afternoon I have been testing the parfociality of my ES82's in my refractor and they work very well.  The best parfocal ep's I have ever come across are the SW LET series, absolutely spot on, no adjustments at all, however, slight adjustments with the ES82's, but not much, but that could have been my unsteady gait.

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I don't think there's any reason why you should just consider plossls, excellent as they maybe.

Maybe if you give people some idea of your budget per eyepiece, they'll happily provide some alternatives.

Fair enough. 

My goal is to find a nice set of eyepieces that can accomplish some nice planetary views.  I would like to be able to do deep space views as well, but these are much less frequent and impressive given that I live in a city with some decent light pollution.  I would prefer to spend the money to get something nice right off the bat vs upgrading often.  4-5 nice eyepieces would be great.  I have no gripes spending $200+ an eyepiece, but maybe the ones that are $4-500 might be a little too much for me.  

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