Does every astronomer need a plossl?

[JOC]

Through luck (if you call it luck - the bank balance might disagree) I am acquiring some useful EP's.   I have some thoughts on some of these and wondering if I still need some of them - thoughts would be useful - listed in order of magnification.

EP's 1.25" 10mm & 26mm Boxed Plossls;  (AFOV unknown, eye relief unknown - need to keep these to sell if the telescope is ever sold in the future)

Celestron Omni Plossl 1.25" 32mm;  50 degree AFOV, 22mm eye relief (this provides a useful low magnification view)

Meade 4000 Super Plossl 15mm; 52 degree AFOV, 9mm eye relief (with its low eye relief this shouldn't be easy to look through, but it is - I like the eye piece and it works splendidly in my Barlow - this is a keeper)

14mm Baader Morpheus 76"; 76 degree AFOV, approx. 20mm eye relief (My first 'fancy EP' - it's like walking across the surface of the moon - too physically heavy to be usefully Barlowed, but this is a keeper)

12mm Meade 5000; 60 degree AFOV, 19.6mm eye relief (Just got this, haven't had a chance to try it, but think I will be impressed - I hope it should be as easy to look through as the Morpheus and am expecting this to be a keeper)

TV 11mm Plossl; 50 degree AFOV, 8mm eye relief (this is the one I'm thinking of losing - but it is my only bit of green and black - am I right in thinking that the 12mm Meade 5000 should provide a superior experience?  I do have EP's that are easier to look through with my glasses on and if I sold this it would go towards the cost of the recently purchased Meade 5000 and BST )

8mm BST Star Guider; 60 degree AFOV, 16mm eye relief (Just got this, haven't had a chance to try it, but think I will be impressed - should be nearly as easy to look through as the Morpheus and am expecting this to be a keeper)

I do also have a Barlow on hand

What do you think, given the fist full above, would the TV Plossl be a great loss?  Do you think I will still get use from it given the other EP's available?

[John]

The Tele Vue plossls are the best of that design that I've used. I don't think the Meade 5000 would beat it in terms of pure optical performance. In fact in those terms I think the TV plossl probably the best eyepiece you have with the possible exception of the Morpheus.

If you put a premium on wider fields and longer eye relief though then the TV 11 and Meade 15mm plossls might not fit the bill and you would not miss them.

 

 

 

 

 

[Littleguy80]

Interesting thread! Hope you don't mind me crashing your thread @JOC! The comment on the quality of the TV plossl made me wonder how they compare to the Baader Genuine Orthos. Pretty much the only eyepiece I'd like to add my collection right now is a 12.5mm BGO. @John optically would you favour the 11mm TV plossl or the 12.5mm BGO? Again apologies for going slightly off topic though I hope a plossl vs ortho comparison will be of interest  

[John]

Probably the 12.5mm BGO but there is not a lot of difference to my eyes. "Your mileage will vary" though

I think there are plenty of experienced observers around the world who either use a set of TV plossls or similarly a set of BGO's / Fujiyama / University HD orthos and those meet all their observing needs.

Not those who need to wear glasses when observing though !

 

[JOC]

11 minutes ago, John said:

Not those who need to wear glasses when observing though

Ah, well you see I am in that camp - I ditched a 8mm TV plossl because I couldn't see through it - no matter how good the quality is if I can't see through it I can't appreciate the quality.

[rl]

Why not sell the Baader, Meade, TV (all of a similar focal length) and get a s/h Delos?

RL

[John]

14 minutes ago, JOC said:

Ah, well you see I am in that camp - I ditched a 8mm TV plossl because I couldn't see through it - no matter how good the quality is if I can't see through it I can't appreciate the quality.

Well you won't find plossls or othos below around 15mm comfortable at all to look through. The eye relief of these designs is around 80% of the focal length of the eyepiece regardless who makes them.

Go for longer eye relief designs such as the Morpheus, Delos or Pentax XW's. Very close to ortho-type optical performance with these. On a lower budget the Vixen SLV's give top notch optical performance with great eye relief.

 

[Littleguy80]

19 minutes ago, John said:

Go for longer eye relief designs such as the Morpheus, Delos or Pentax XW's.

Similar question to my previous one but how does the 5mm Pentax XW compare to the 5mm BGO optically? The Pentax seems to be very popular as a premium eyepiece

[Alan White]

I really like my TV 11mm Plossl, get on with it well, use Tak LE at shorter fl for the better eye relief.

Eyepieces are so personal taste it’s hard for you to make a truly balanced view from others personal views in my opinion.

You can always do what many here do and hold onto them all and have a huge collection of course, if you can afford to do so financially and space wise.

[Moonshane]

I think the answer to your basic question is no but I'd really miss mine for solar system and doubles

[Ricochet]

If it was me I would probably drop the 15mm and 12mm. 

The 15 is too close to your best eyepiece, the 14mm, and I can't see when you would choose to observe an object using the 15 instead of the 14. You'd be better off with something in the ~20mm range to split your 14 and 32mm eyepieces. You like the performance of the 15 in the barlow, but this is effectively a 7.5mm which is pretty much the same as your 8mm. Again, there is no need for both. 

The 12mm is also too close to the 14mm in my opinion. 14-11-8 gives more even splits than 14-12-8. However, the better eye relief of the 12 may swing things in its favour in practice. 

[Stu]

I have, in the past, found the 32mm and 11mm TV Plossl to be my favourites, at least most used. The 11mm was very sharp as a solar eyepiece in a PST and the 32mm a good low power and gave a larger exit pupil in a Mak than a 24mm 68 degree with a similar fov.

I think the BGOs are a smidge sharper but then it is not an exact focal length match so hard to be sure that other effects are not causing the difference.

I currently have no plossls, but would add a 32mm back in at some point I think. 

[Tim]

I use the assorted collection of cheap/rubbish Plossl's I have as dust stoppers when I can't find the 1.25" inserts......

That said, if I can't find a target in my better eyepieces I will revert to a cheap 32mm plossl for the wider view. Saving up for a 31mm Nagler 5 but until then the 32mm cheapy will be on hand!

[ronin]

I would say No, they don't.

A lot of plossl use and recommendation came from several years back when the TV plossl  was the almost standard upgrade from the supplied items. However things changed: TV plossls had remained a good price for a few years, then TV upped the cost and they jumped significantly, Alan at StL began selling the BST Explorers, these were originally £36 each. The BST's were very good and cost wise were a fair bit less then the TV plossl's.

Also at the time scopes tended to still come with a cheap plossl as standard, now it is Huygens and Ramsdens. Bet lots of us have the much supplied Meade and Celestron Plossl's hiding away in a box somewhere. I have a couple of Celectron ones and I have never owned a Celestron scope, so not sure where they came from, and they were not bad eyepieces. The grey Celestron ones looks good as well.

Plossl's can be very sharp but they have the disadvantage of variable eye relief. Vixen NPL's are reported as good but they are now a match in cost for the BST's.

The BST's may, only may, lose out in some aspects but they gain in others and they are very easy to use and get along with. A much ignored aspect.

Someone says sell whatever and get a Delos, Why do I want a single eyepiece? If performance is the point then I sincerely hope the Delos is a lot better - actually know they are from a direct comparison - and I bet Al is happy to know the Delos is a lot better. The choice is 6 BST's or 1 Delos. I will settle for the BST's.

So really there is no reason not to go from the supplied Huygens/Ramsdens to BST and miss plossl out. Other then clarity and sharpness of the TV, and may be the Vixens which are now a price match but I do not know specifically of their performance, I do not think anyone will go wrong jumping to the BST's, so no plossl intermediatory.

I have the BST's, also have the TV plossl's, these days I never use the TV's. And no, I am not intending selling them.

[Louis D]

13 hours ago, JOC said:

12mm Meade 5000; 60 degree AFOV, 19.6mm eye relief (Just got this, haven't had a chance to try it, but think I will be impressed - I hope it should be as easy to look through as the Morpheus and am expecting this to be a keeper)

I have the entire set of HD60s, and the 12mm is quite good, though not perfect to the edge like a Delos.  You should be well pleased with it.  The 9mm is the sleeper of this line, though.  I couldn't detect any image deterioration at the edge with a star test.  I haven't put them through their paces for contrast, ghosting, or resolution yet.  I got them just before mosquito season set in.

5 hours ago, ronin said:

Someone says sell whatever and get a Delos, Why do I want a single eyepiece? If performance is the point then I sincerely hope the Delos is a lot better - actually know they are from a direct comparison - and I bet Al is happy to know the Delos is a lot better. The choice is 6 BST's or 1 Delos. I will settle for the BST's.

Probably good advice for those on a budget.  I already have a nice collection of XLs, XWs, Delos, Panoptics, Naglers, ES-92s, etc., but I just wanted to see how these new 60 degree step-up eyepieces perform for myself, so I picked up a used set of Meade HD60s to test over time.  So far, I've been impressed with them.  The 18mm and 25mm aren't all that great (edge astigmatism, mostly), but the rest are really nice values.

12 hours ago, Littleguy80 said:

Similar question to my previous one but how does the 5mm Pentax XW compare to the 5mm BGO optically? The Pentax seems to be very popular as a premium eyepiece

I have the 5.2mm Pentax XL, and I use to resolve globular clusters in my 8" dob quite successfully from edge to edge without any change in resolution as it drift across the field.  I don't know how a BGO would compare, though it would be hard to improve upon that level of performance.  That, and I like to observe with eyeglasses due to severe astigmatism that affects the view somewhat even at 1mm exit pupils.

 

7 hours ago, Stu said:

I currently have no plossls, but would add a 32mm back in at some point I think. 

I use a pair of 32mm plossls in my binoviewers to both max out my field of view even though it is vignetted by the 23mm clear aperture of the viewer and to maximize surface brightness (exit pupil) on nebula to make them stand out better.  I have a pair of 26mm plossls as well, but their limited eye relief due to recessed eye lenses makes them annoying to use.  They just about max out the unvignetted field of view.

[JOC]

What a great discussion folks, I love the number of replies with a 'but' in the answers!  I probably don't really have to sell any of them unless I get really hard up, but it's going to be interesting to see how many of them I start to favour and how many naturally fall out of use.  I wonder if any will start be favourites for certain types of objects - for example, the Morpheus is great on the moon!  Also, there is an outside chance that some nights I might take the little vixen OTA out as well and then might be pleased that I have some duplicates, I guess it might even be the case that some are better in the baby Vixen and some better in the Dob.

[Paul73]

I've got a few TV Ploses. True they are sharp and cheap (comparively). But they are from another age. And, it shows in terms of edge performance. Bang in the centre though, they shine. Mine are used in the main scope and for the travel setup. Otherwise, it is Delos all the way....

Paul

 

[alanjgreen]

Joc,

No, I do not want any 50 degree FOV eyepieces in my collection, to answer your question!

- I had to sell a perfectly good Delite eyepiece because the FOV was way to narrow in the dob and that was a great EP!

I am surprised that the 50 degree FOV does not drive you mad in your dob. I can only imagine the amount of nudging you must have to do! (Especially at higher powers)

- using the 76 degree Morpheus must be a dream compared to all those plossls?

I think dob users benefit the most from wide field EPs (I know that I do). A lovely 20mm+ 82 or 100 degree EP would be a game changer in your dob

-  imagine all the time you would have to watch the object drift across the view - lovely?

- imagine how much more relaxed you would be not constantly hugging and pushing the dob here and there? (When relaxed you will "see" more)

I'd be looking to move on all those plossls, keeping the Morpheus and BST.

Add a couple of well picked focal length wide FOV EPs and you could be down to a set of 4. I wouldn't want to push you to any particular brands but I would encourage you to go wider  

I would also try to get a wider spread of focal lengths in your EPs, they all seem very similar (1mm here and there, visually no real magnification difference). In my big dob, 4 EPs has been all I have needed with 21, 13, 10 and 8 giving me roughly 100, 150, 200 and 250 magnifications. I might need a bit more power for Mars in a few years time (but I do have other EPs in my binos box to swap in for that purpose).

- I would calculate the magnifications that your EPs are giving you then put those within x20-x30 of each other together and pick your favourite to keep then sell the others to fund a wide field EP from a missing magnification range but it's not up to me  

Alan

[John]

The OP wears glasses when observing I believe. Many 82 and 100 degree eyepieces (which I do love using in my dob  ) have eye relief which is a little tight for many glasses wearers.

 

[Paul73]

I believe that the ES 92° range has Delos rivalling eye relief. I’ve never looked through one though.

paul 

 

[Tim]

6 hours ago, alanjgreen said:

 

I think dob users benefit the most from wide field EPs (I know that I do). A lovely 20mm+ 82 or 100 degree EP would be a game changer in your dob

When I first got my dob I asked some learned friends "if you could only have one EP, which one?".  21mm Ethos was the overall answer. I didn't realise what the fuss was about until I got the chance to use one. Just like looking through a window into the sky, lovely!

[scarp15]

Televue Plossls can be useful to dob users in the Low and medium / low power range, where they can provide nice clean lunar and certain tight open cluster views and additionally the 32mm as a finder. Eye relief is good up to the 20mm plossl (14mm). The four glass elements, 50 degree field, make them particularly suited, when combined with a filter for gaining contrast and brightness in searching for certain reflection, faint emission and dark nebula structures, particularly when a bright star needs to be kept out of the field of view. The Televue 11mm and 8mm Plossl are sharp and absorbing planetary eyepieces, if you are fine with the tight eye relief, worth considering for a scope with tracking capability such as an 8" SCT.

[JOC]

4 hours ago, scarp15 said:

particularly when a bright star needs to be kept out of the field of view

I hadn't considered that there might be instances when there could be benefit to a smaller field of view - that's a different thing to think about.

[Louis D]

13 hours ago, Paul73 said:

I believe that the ES 92° range has Delos rivalling eye relief. I’ve never looked through one though.

paul 

 

Yes, it views very much like a Delos on steroids.  I have the 17mm and it shows no astigmatism or field curvature right out to the edge just like a Delos, but 20 degrees wider.  I've checked bright stars on both sides of focus at the field stop, and the diffraction rings are textbook round and concentric.  The 14mm Morpheus is a mess at the field stop by comparison.  All sorts of astigmatism and field curvature and yet 16 degrees narrower.

The ES-92 views like looking out a picture window.  No cramming your eye inward to take in the whole view.  It is quite usable with eyeglasses.

10 hours ago, Tim said:

When I first got my dob I asked some learned friends "if you could only have one EP, which one?".  21mm Ethos was the overall answer. I didn't realise what the fuss was about until I got the chance to use one. Just like looking through a window into the sky, lovely!

Except you can't take in much more than about 70 degrees with eyeglasses when using any Ethos eyepiece.

[Tim]

6 hours ago, Louis D said:

Except you can't take in much more than about 70 degrees with eyeglasses when using any Ethos eyepiece.

Yes, that is an issue. Televue make a strong case for their Dioptrx attachments, but I know very few people who actually use them. Anybody have any insights on them?

http://www.televue.com/engine/TV3b_page.asp?id=54