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In praise of the 32mm TeleVue Plossil


Caldwell14

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1 hour ago, mikeDnight said:

With my 31 Nagler the edge stars were out of focus when the centre field was sharp, but by focusing the 75% zone it gave a reasonable view across the field though technically it wasn't in true focus.

Is that not as likely to be field curvature of the scope as much as anything else?

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Yes, but in my mind and for whatever reason, unless the stars are sharp across the entire field then the eyepiece isn't really giving a true real field. If for example, the stars in the outer 25% of a 70° AF  are not sharp or in focus then I might as well be using a narrower field eyepiece that is sharp or sharper towards the edge.

May be I'm a little odd, or even a lot odd, but over the last couple of months I've really enjoyed using quality but simple eyepiece designs over the bulky, wide field designs. These little gems are so sharp and pure that I'm happy to let go of the wide field hand grenades which are often much larger and heavier than they need to be, all in the name of fashion. 

To fund my Tak I sold many of my Televue eyepieces which were mainly 2" fit and kept my XW's, which I thought gave a better view anyway. But this left me with mainly highish power eyepieces, so one evening my mate Paul loaned me a 24mm Plossl. Wow it was good! There was a sharpness and clarity to the view that i hadnt seen in years. I then decided to set myself up with some small but high quality eyepieces from Takahashi but was dissapointed with the performance and comfort of some of them. I then bought a set of Fujiyama ortho's but some were faulty and I sent them back. Although I wanted a complete set of quality 'simple' eyepieces, I was unable to find a set, so I've had to cherry pick from different brands until I feel reasonably happy. 

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I do see the point in not incurring the extra bulk, weight and cost if the extra field is not worth it to you. Especially if your mount is motorized.  :happy11:

Perhaps a bit more pertinent to the OP, I am curious as to how the TV 32mm Plossl stacks up against the 24mm Panoptic. Same true field, different magnification. Neither qualifies as a hand granade. Can the simplicity of the Plossl's design provide a more pleasing view? Or does the "majesty factor" prevail?

I have acquired a TV 32mm Plossl from a fellow SGL member and after I return from hols, I intend to find out.

:icon_biggrin:

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I have a Meade 4000 32mm Plössl and it gives lovely crisp views with a nice black background. I do prefer my widefield eyepieces eyepieces though, especially the LVW series.

As an aside, don't worry about spelling Plössl. From what I've seen I'm about the only person on the planet who writes it correctly... :ohmy::tongue2:

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I spent a happy night with just a TV 32mm Plössl  (plus eyecup extender) in my 12" dob galaxy hopping last year.  Spotted dozens during that session :icon_biggrin:

I find the 24mm Panoptic provides a similar view with a darker background sky here though, as does the 21mm Ethos (more sky !) so I don't tend to use 30mm+ eyepieces that often apart from on the largest deep sky targets.

I believe the pronounciation is "pl-oo-eh-sl" :icon_biggrin:

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  • 2 weeks later...
On 16 September 2017 at 09:33, iPeace said:

I do see the point in not incurring the extra bulk, weight and cost if the extra field is not worth it to you. Especially if your mount is motorized.  :happy11:

Perhaps a bit more pertinent to the OP, I am curious as to how the TV 32mm Plossl stacks up against the 24mm Panoptic. Same true field, different magnification. Neither qualifies as a hand granade. Can the simplicity of the Plossl's design provide a more pleasing view? Or does the "majesty factor" prevail?

I have acquired a TV 32mm Plossl from a fellow SGL member and after I return from hols, I intend to find out.

:icon_biggrin:

32mm Plossl has more eye relief than the 24mm Panoptic. 

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And it has arrived, a very nice eyepiece. Nice big lens to look through, and indeed more eye relief than I'm used to - immediate blackouts if I get in close like with Naglers, so a slight adjustment necessary but fully intuitive. Now to wait for nightfall - and a gap in the clouds.

:happy11:

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18 minutes ago, John said:

Brings back memories - I think I've owned 3-4 of those over the years :icon_biggrin:

Having used and enjoyed the 31mm Nagler Type 5 in my TV-85, I am looking forward to trying this very similar focal length. I have no illusions that the view will be as good - certainly not as wide - but it may be very good nonetheless.

:happy11:

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Worth a try Mark. I have a 30mm Vixen NPL which I have similar plans for this winter plus the 24mm Panoptic for a similar true field but smaller exit pupil. I think I've got closest to seeing the HH with the 18mm Baader Classic Ortho but I'm happy to try a range of other options.

 

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  • 5 weeks later...

Gooooooooooooooodness.

:happy11:

I just got in from a shortish session, in which I compared the TV 32mm Plossl to the 24mm Panoptic - in my TV-60.

Many more experienced and more knowledgeable souls will not be surprised at what I experienced, but it was very interesting and new for me.

I was certainly prepared for the 24mm Panoptic to be "better", but was surprised by the extent to which this is indeed so!

The 32mm Plossl is very nice, but - at least in this scope - the view gets progressively less sharp towards the edges. Quite dramatically, to my eye.

I have thoroughly enjoyed using more expensive eyepieces in the past (and will continue to do so), but this has given me new insight into what I was paying for.  :rolleyes2:

Don't take this as disapproval of the Plossl. My current assumption is that it will give progressively better views in more suitable (bigger, slower?) scopes.

I have yet to try it in the TV-85, so to be continued. I do know that it won't be traveling with the TV-60.

I like the idea of having a big(ish) Mak in which it may be a lot nicer - but that's a whole other kettle to be decided on.

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If the 32mm is like the 24mm, the field is not as flat as inthe more complex designs. ie. Jupiter can gain a slight rugby ball type of appearance. This isn't normally a problem in a long eyepiece as long as you stay away from the sun and moon. Can't remember any significant star quality issues towards the edges.

Paul

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The TV 32 plossls (and other focal lengths from that range) that I've used have seemed pretty much sharp to the edge even in my F/5.4 12" dob :icon_scratch:

So is the 24mm Panoptic. I tend to prefer the smaller exit pupil that the 24 Pan produces and the wider view is always welcome :icon_biggrin:

 

 

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4 hours ago, John said:

The TV 32 plossls (and other focal lengths from that range) that I've used have seemed pretty much sharp to the edge even in my F/5.4 12" dob :icon_scratch:

So is the 24mm Panoptic. I tend to prefer the smaller exit pupil that the 24 Pan produces and the wider view is always welcome :icon_biggrin:

 

 

That's sort of what I was expecting; F/6 shouldn't really be a problem for any of TV's offerings, should it?

The 24mm Panoptic is clearly sharp to the edge, but this 32mm Plossl in this scope certainly is not.

Makes me wonder...

:icon_scratch:

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20 minutes ago, iPeace said:

That's sort of what I was expecting; F/6 shouldn't really be a problem for any of TV's offerings, should it?

The 24mm Panoptic is clearly sharp to the edge, but this 32mm Plossl in this scope certainly is not.

Makes me wonder...

:icon_scratch:

That sounds strange. Given the smaller afov I would expect the Plossl to be at least as good as the Pan. Not done a side by side so don't know for sure. Perhaps it was more field curvature in the scope which shows more at longer focal lengths??

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Thanks Mike ( @iPeace ) for your comparison between the 24 Pan and 32 Plossl. :)

I have been thinking about the 32mm plossl for ages, but never pressed the button to get one. On the TV60 it gives ~11x which is a rather low magnification to me.

Eventually, I bought a Vixen NPL 30mm  when they were discounted on FLO. This lasted less than 1 month. I did my very best to like that eyepiece, and to be fair with it I felt it is a very good eyepiece on a slow telescope, but the edge was miserable to my eye on the TV60 f6. Not that I am a field stop OCD, but a blurring 15-20% on a 50 deg AFOV is way too noticeable and distracting. On axis it was sharp. I left it go for less than £30 to a member over here after pointing out that it was a good eyepiece IF used with not less than F8-F10 telescopes. Glad that it found a new home and that the owner is happy with it. 

The experience with the NPL 30mm, made me think that this telescope was more demanding and that the TV 32mm Plossl would have been at home with this telescope. Considering Mike's report, this does not seem the case though. Moonshine could be right about the inverted lenses. May I ask whether you can reach focus at the edge? A trivial object to check this is the Moon. The TV60 suffers from field curvature (as every other short tubes without additional flattener). I would not be surprised if you need a tiny focus adjustment at the edge, but if you cannot reach focus at all (e.g. blurred image at the edge), that's different. I have a 20mm TV Plossl which cannot show a clear edge. It is sharp on axis with a rather good colour tone, but the image is distorted at the edge (edge.... last 30% of the field!). It was suggested that the lenses could have been placed the other way around. I tried to open it, but did not manage to as it was heavily cemented. Mine was bought new 20 years ago. 

See whether this thread is familiar with your experience: 

 

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1 hour ago, Moonshane said:

Is it new? If bought used maybe the elements were taken out for cleaning and put back incorrectly?

There are only four permutations so if it's a possibility it's worth trying

It's not new; I will ask the previous owner about this...and then perhaps give it a try. If it's already been done before, it shouldn't be too difficult.

:rolleyes2:

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1 hour ago, Piero said:

Thanks Mike ( @iPeace ) for your comparison between the 24 Pan and 32 Plossl. :)

I have been thinking about the 32mm plossl for ages, but never pressed the button to get one. On the TV60 it gives ~11x which is a rather low magnification to me.

Eventually, I bought a Vixen NPL 30mm  when they were discounted on FLO. This lasted less than 1 month. I did my very best to like that eyepiece, and to be fair with it I felt it is a very good eyepiece on a slow telescope, but the edge was miserable to my eye on the TV60 f6. Not that I am a field stop OCD, but a blurring 15-20% on a 50 deg AFOV is way too noticeable and distracting. On axis it was sharp. I left it go for less than £30 to a member over here after pointing out that it was a good eyepiece IF used with not less than F8-F10 telescopes. Glad that it found a new home and that the owner is happy with it. 

The experience with the NPL 30mm, made me think that this telescope was more demanding and that the TV 32mm Plossl would have been at home with this telescope. Considering Mike's report, this does not seem the case though. Moonshine could be right about the inverted lenses. May I ask whether you can reach focus at the edge? A trivial object to check this is the Moon. The TV60 suffers from field curvature (as every other short tubes without additional flattener). I would not be surprised if you need a tiny focus adjustment at the edge, but if you cannot reach focus at all (e.g. blurred image at the edge), that's different. I have a 20mm TV Plossl which cannot show a clear edge. It is sharp on axis with a rather good colour tone, but the image is distorted at the edge (edge.... last 30% of the field!). It was suggested that the lenses could have been placed in the other way around. I tried to open it, but did not manage too as it was cemented. Mine was bought new 20 years ago. 

See this post if it is familiar with your experience: 

 

I didn't try to focus the view at the edges - I guess I wasn't quite in fault analysis mode just then.

Thanks for this, I will ask the seller about this, see if it's known to have been opened up before and then decide what to do. If it has been opened up before, there shouldn't be any cement keeping me from doing it again.

:happy11:

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6 minutes ago, iPeace said:

I didn't try to focus the view at the edges - I guess I wasn't quite in fault analysis mode just then.

Thanks for this, I will ask the seller about this, see if it's known to have been opened up before and then decide what to do. If it has been opened up before, there shouldn't be any cement keeping me from doing it again.

:happy11:

If the edge appears blurred, whatever you do with the focuser, you should also see this in daytime.

If this is the case, there is a chance that one group was mounted wrongly. If there is no cement, it should be easy to fix.

Fingers crosses! :) 

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