Why would somebody use Plossls in this case...?

[emadmoussa]

I think this is completely subjective and up to   personal preference.

Having moved from Plossls to wide field eyepieces I ended up selling most of my Plossls as they weren't used as much . I still have - I think - 3 Plossls that I use for quick finder scope aligning and collimation testing.

But I can still see a lot of members who still use both Plossls and wide field EPs...even with similar focal length. Any reason for that?

[nicks90]

i still use plossls for my high power stuff, and my meade 6.4mm plossl is absolutely pinsharp and beautiful in my 12" dob when viewing jupiter!

Why do i still use it? Well i dont need a 70deg+ field of view when looking at a point object like jupiter or double stars at x230. Also as I cant afford lots of very high quality wide angle eps that have edge to edge distortion free at F5, it would just annoy me seeing jupiter warp out of shape as it reaches the outer 30% of the field of view. Luckily my dob is a tracking SW truss dob, so it generally doesnt need nudging and doesnt drift across the ep, so a 55deg fov is fine and the image quality is probably better than a cheap widefield.

For widefield, i want WIDE FIELD, and that pretty much (imho) means low power acres of sky wide field - not high power. So i have two decent widefield ep (soon to be 3) for sub x100 mag where finding the object and framing it beautifully is beneficial, but i doubt i will ever expand my ep selection to include 70deg eps under 12mm focal length. Its just not worth it.

edited to add: just looked in stellarium ocular view and added an 82deg 6.4mm ep and compared the view of jupiter at 11pm to my meade 6.4 plossl, the view included one mag 12 star near the edge. hmmm, dont see the point.

[Moonshane]

I have some close comparisons :

26mm nagler - 25mm TV Plossl

13mm Ethos - 12.5mm BGO

16mm Nagler - 15mm TV Plossl

broadly I use the plossls for anything bright (moon, venus, jupiter, mars) as I find they offer better contrast and detail to my eyes. they are also much lighter and for my 6" f11 newt, balancing is quite critical. sometimes you need to have brightr stars out of the field of view to see the nearby faint stuff and again plossls are good for this.

[Luke]

I use a pair of 25mm Tele Vue Plossls in binoviewers, mainly for lunar observing. Compact, light, very sharp, comfy, work well with my binoviewer, good eye relief at this focal length, cheaper than Delos. I love them to bits.

[AlexB67]

I am not going back, even going form 60 to 70 is a big jump, but for me it is mostly about eye relief above anything since I wear specs, so high power plossls are not for me. While I can get away not wearing them when observing, I like the luxury of both. No doubt though that a good plossl with a quality 50 degrees I am sure gives great views, not that I ever owned one. If you have a very fast scope why waste the money on extra FOV when Coma will largely make that extra FOV annoying. If you can afford a CC you can probably afford UWAs anyway      

I can think of another good reason in a situation where personally I may like to use one, less elements, high transmission. If you are at the edge of detecting a DSO that extra transmission may just allow you to that bit more, that is assuming everything else being equal in terms of coating and glass quality compared to a 6 or 7 element eyepiece. 

[michael.h.f.wilkinson]

The main reason I do not use Plossls is that at long focal lengths I prefer wide-fields, and at short focal lengths the eye relief bugs me.

[A McEwan]

Yup, I use Irthos as well as Naglers and ES UWA eps. For me the Orthos are far superior in revealing ultra fine planetary detail. In a direct comparison between the Nagler 13 T6 and 12.5 Ortho observing the Moon, there was another advantage: the Moon was actually round in the Ortho. As it drifted towards the edge of the Nagler's field, the Moon clearly became oblate.

UWA eyepieces usually have some amount of barrel ir pincushion distortion that does not exist in Ortho or Plossl eyepieces.

Also for h-alpha viewing "simpler" eyepieces perform noticably better.

Ant

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[rwilkey]

I think a lot of people make a mistake by just going over to widefields or 'upgrading' to 2" and so on, as the humble plossl and its companions in the 1.25" range are essential for viewing planets, Moon and double stars, you have got to have a variety in your collection for viewing different objects. 

[Macavity]

Plossls, Orthos (Essentially a microscope eyepiece?) all have their USES (devotees).

There is the "framing" aspect too. Wide field eyepieces need not be "sharp to the edge".

No bad thing to actually READ about the subject generally, before buying / selling...

[michael.h.f.wilkinson]

I would not advocate Naglers for planetary, but for those of us who need glasses when using a scope there are several planetary EPs VERY close to Orthoscopic performance (Vixen NLV, TV Radian, Delos, Pentax XL/XF/XW) but give sufficient eye relief, and have a wider field (useful in non-tracking scopes). Distortion is very limited to absent in my XWs and lone Delos. Having said that, I do find the humble 20mm Plossl of my kids' scope a very impressive little performer at just 15 euro (14.95, actually). If you do not need long eye relief, a quality Plossl is going to be very hard to beat (except by a monocentric, ortho, or (dare I say it) XW). 

[emadmoussa]

I'm mainly a DSO oberver. While Plossls were a massive improvement over the stock eyepieces, they were also behind for wide field DSO observing. There's nothing wrong with them, they simply served a purpose and still do.

[emadmoussa]

No bad thing to actually READ about the subject generally, before buying / selling...

??

[alan potts]

In my books Plossl eyepieces are very sharp indeed and as good as any for planetary work. I do not have any at the moment but I have not overlooked them, I would really like some TV plossls and intend to be on the hunt next time over in the UK. I agree with Robin many just get swept along by the wide field of view, I am very grateful to John for switching me on to orthoscopics, and I haven't finished my collection of them either.

Alan

[Macavity]

??

You are an *experienced* Astronomer now. You have (I sense) an enviable eyepiece collection. 

What are YOUR opinions on the ones you have acquired? Do WE know ANY better than you?

We can endlessly reiterate what we (claim to!) know about "Plossls". But are we progressing? 

There is a WEALTH of internet information on the relative merits of eyepiece TYPES and more.

After a lot of probing, I learned the "real deal" re. Eyepieces from some knowledgable CN guys!

But I had to know the right questions... to "know my place" (a fair bit. lol) and persist a LOT!

Just me being a miserable GIT? But ever encouraging you to think / READ a bit - That's all. 

[Qualia]

I can still see a lot of members who still use both Plossls and wide field EPs...even with similar focal length. Any reason for that?

I think there are many factors to persuade one to use quality plossls and orthos over larger, wider-field eyepieces. Even as little as 1mm increase or decrease in the mag - about 10% to 15% difference of magnification - can be quite surprising which is the main reason why I feel most planetary observers will have a tidy run of high-mag EPs.

For argument's sake, let's assume we have an f/5 10" and this average run consists of about seven or eight focal lengths, say, something like, a 5, 6, 7, 8, 9, 10, & 11mm.

It becomes obvious that unless one has a lot of cash, a lot of eyepiece's cases, not much need for a planetary grab n go, nor the necessity to travel out to a dark site that often, such a move of buying into a large run of quality wide-fields (for our proverbial f/5) borders on the ludicrous.

But we can go further.

The planetary observer can also reply that the smaller field quality plossls and orthos will give a nicer framing, a better contrast, and will surrender more detail to the eye. Indeed, from my own subjective experience, comparing the TV 11mm plossl with the 10mm Delos, the former reveals more detail to my subjective eye when it comes to observing Jupiter, the Moon and detail on the Sun.

In such cases as suggested, the question isn't 'why do folk still use plossls and orthos?' but rather, 'why are there folk who only use wide-fields?' And I think the answer is simple: they don't really enjoy planetary and lunar observing.

Luckily there's room for everyone in this beautiful hobby

[RikM]

I have TV Plossls in 13 and 21mm and a 40mm that belongs with the Pronto. I don't use them for observing myself but have these for public observing events where I don't really want to risk the XW's.

If I could get on with the tight eyerelief of shorter FL Plossls I would probably use them (actually Orthos) over the 70° because to my eyes, the smaller image circle gives the effect of higher apparent magnification. I get round it by using 70° EP's with very low distortion so I can let objects drift across the field.

[emadmoussa]

You are an *experienced* Astronomer now. You have (I sense) an enviable eyepiece collection. 

What are YOUR opinions on the ones you have acquired? Do WE know ANY better than you?

We can endlessly reiterate what we (claim to!) know about "Plossls". But are we progressing? 

There is a WEALTH of internet information on the relative merits of eyepiece TYPES and more.

After a lot of probing, I learned the "real deal" re. Eyepieces from some knowledgable CN guys!

But I had to know the right questions... to "know my place" (a fair bit. lol) and persist a LOT!

Just me being a miserable GIT? But ever encouraging you to think / READ a bit - That's all. 

Believe it or not I read a great deal on the subject. And like I mentioned in the beginning the whole thing seems subjective and based on personal preference. I was simply gauging what other people's points of view were. It's nice to reciprocate opinions as it gives a fresh perspective into the field.

Well, I'd think twice before calling my collection ''enviable'' The expensive ones are yet to be received...so I'll hold my breath until then.

[Macavity]

Believe it or not I read a great deal on the subject. And like I mentioned in the beginning the whole thing seems subjective and based on personal preference. I was simply gauging what other people's points of view were. It's nice to reciprocate opinions as it gives a fresh perspective into the field.

Well, I'd think twice before calling my collection ''enviable'' The expensive ones are yet to be received...so I'll hold my breath until then.

Emad, I really enjoy your posts - They are genuinely refreshing! I'm sure you do "read around" the subject. If I wondered

about the generic (subjective!) properties of Plossl etc. eyepieces, I might simply tackle it in a different (boring?) way.

Enviable? But did you ever get anywhere with the Skywatcher "Spaceship" Eyepiece? I think you bought one...

http://www.firstlightoptics.com/skywatcher-eyepieces/sky-watcher-swa-70-eyepieces.html

Not a Plossl, but with no reviews as yet, I STILL genuinely wonder - And would value...

[emadmoussa]

Emad, I really enjoy your posts - They are genuinely refreshing! I'm sure you do "read around" the subject. If I wondered

about the generic (subjective!) properties of Plossl etc. eyepieces, I might simply tackle it in a different (boring?) way.

Enviable? But did you ever get anywhere with the Skywatcher "Spaceship" Eyepiece? I think you bought one...

http://www.firstlightoptics.com/skywatcher-eyepieces/sky-watcher-swa-70-eyepieces.html

Not a Plossl, but with no reviews as yet, I STILL genuinely wonder - And would value...

Yes indeed. I've had the 3.5 version for a while now. It's a big chunky eyepiece. Eye relief and optical quality are equally very good. On the 6" refractor it's very good on doubles, but average on planets & good on the moon. Not exceptional. In the 10" Dob seems to work impressively on the moon. Very sharp and free of coma. I guess the field of view is not wide enough at this focal length to make coma and astigmatism very noticeable. But at this mag a manual alt-azimuth mount was quite a race

I used it briefly in my 102ED, the target was Jupiter and it was an overkill. Was quite difficult to reach focus. In the same scope star test was satisfactory though.

[John]

The only duplicate focal lengths I keep in my eyepiece case are a 25mm X-Cel LX which is my Horsehead Nebula eyepiece and a 6mm Baader GO which I use for splitting Sirius. Otherwise I'm doing all my viewing with Nagler, Ethos, Radian and Pentax XW eyepieces now. The Ethos 6mm has shown superb views of Jupiter and the Moon over the past few nights 

[emadmoussa]

The only duplicate focal lengths I keep in my eyepiece case are a 25mm X-Cel LX which is my Horsehead Nebula eyepiece and a 6mm Baader GO which I use for splitting Sirius. Otherwise I'm doing all my viewing with Nagler, Ethos, Radian and Pentax XW eyepieces now. The Ethos 6mm has shown superb views of Jupiter and the Moon over the past few nights 

Horsehead Nebula EP?

[YKSE]

The only duplicate focal lengths I keep in my eyepiece case are a 25mm X-Cel LX which is my Horsehead Nebula eyepiece and a 6mm Baader GO which I use for splitting Sirius. Otherwise I'm doing all my viewing with Nagler, Ethos, Radian and Pentax XW eyepieces now. The Ethos 6mm has shown superb views of Jupiter and the Moon over the past few nights 

Is there any specific reasons for that 25mm X-cel LX instead of a 25mm TV plössl or astro Hutech Ortho?

I seems to rember that you mentioned the eye placement issue with the Ortho.

[John]

Horsehead Nebula EP?

Yep - they recommend a narrower field of view (to mask out certain stars adjacent to th HH nebula) and an exit pupil within a certain range to get the most out of the H-Beta filter under the sort of skies I usually observe under. With my 12" scope 25mm is the right focal length and the 1.25" format keeps the FoV down. It's all about tilting the odds slightly in my favour with this challenging object 

[John]

Is there any specific reasons for that 25mm X-cel LX instead of a 25mm TV plössl or astro Hutech Ortho?

I seems to rember that you mentioned the eye placement issue with the Ortho.

A TV plossl 25mm would be a good alternative as would a 25mm ortho if I can find one with a nice deep eye cup. The X-cel LX came up at a good price and it's a decent eyepiece so I thought I'd try that but I may well give some other options a try too.

TV plossls seem to have light transmission figures higher than most other eyepieces which adds to their attraction for this task.

[earth titan]

I've looked through plenty of eyepieces. Some I can afford and many I can't. In my experience they are all limited in one form or another.

I have settled on the TV Plossls. From those I've looked through they seem crisper and more 'contrasty' than many of the widefields and the price makes them a good deal.