Why Buy New Eyepieces?

[Stub Mandrel]

Another one of my more foolish questions...

The benefits of different scopes are fairly easy to understand, but for eyepieces it's more difficult.

As a glasses wearer I understand good eye relief can be handy (although I normally take my specs off).

I can understand the benefits of a wide field of view if you want to see larger objects rather than planets and that expensive eyepieces will have better quality views right to the edge of the FOV.

When I look through my standard Skywatcher 10 and 25mm EPs I can see a clear view with no annoying colours or fringes, and I can tell that the view is sharper than the 'budget' Bresser EPs.

I may be in the position of someone who has upgraded from  a transistor radio* to a ghetto blaster and can't imagine what a proper set of hi-fi separates would sound like.

Can anyone give me an idea of what sort of benefits I might get from upgrading eyepieces? I'm not really talking about esoteric ones costing hundreds of pounds but looking at the Skywatcher ones up to about £50 for example? Are these significantly better than the stock EPs?

Would I be better buying replacements for the 10 and 25, or would adding a 32 or 40mm Plossl (for wider views) and a 7mm (for planets) bri8ng me more rewards?

*for the younger audience, a cheap[ transistor radio used to sound even tinnier than a iPhone.

[Knighty2112]

For myself I see a big difference for eyepieces less than 10mm. I had a bog standard 4mm EP that came with my first 70mm frac about 5 years ago. When I used that even on my later better quality scopes the view through it was dire. I bought a 4mm Celestron Omni EP and the view through it is much clearer and better. For the standard EPs you normally get with most scopes (10mm and 20mm) I don't think the view is massively different or better, but for less than 10mm downwards the quality of view is much better. In fact when I use my 2 X Barlow lens with it when the nights are good I still get good views through it, something that even on the best night I never would get with the standard 4mm EP supplied.

[laudropb]

It is a good idea to stick to the supplied eyepieces while you learn how to use your scope and your way round the sky. Eventually you will realise the views given, especially by the 10 mm ep canbe improved by buying a more expensive ep . I bought a Celestron XL 9 mm ep. The view is much crisper and colours are much more obvious. Also it is nice to have a range of eps. It is very nice to be able to use a range of magnifications.

[Piero]

Just a note. If 32mm and 40mm you mentioned are tele vue plossl, then they have the same field stop (27mm I think) and therefore the differences will be magnification and exit pupil, not the field of view.

The reason for having more eyepieces is to cover a wider range of targets. A way to define a useful range for your telescope is to consider the exit pupil. At least I found this very helpful when I bought my set.

[John]

I don't buy new ones - I've expensive tastes in eyepieces so they have to come from the used market

Most eyepieces perform very well in the central area of the field, or "on axis" as it's called. Generally what you get for more £'s are wider views, more eye relief (critical in short focal lengths if you wear glasses) and stars that remain looking like stars over most, or preferrably all. of the field of view even with fast scopes.

I've very rarely found a more expensive eyepiece showing anything that less expensive ones don't but the "prizes for quality" seem to be:

- darker background sky

- less light scatter and ghosting around bright objects

- crisper resolution of fine detail

- no CA or colour tint introduced to the image by the eyepiece optics

Wider fields of view give more drift time for undriven scopes, fit larger objects in or frame smaller ones in the context of their background starfields nicely and can also help retain a more effective exit pupil.

You can certainly live with lower cost eyepieces and enjoy the hobby but I feel that an exception would be the stock 3 element items which I don't think allow a scope to peform to it's full potential.

[glynnlondon]

I would also recommend sticking with the stock eps for the time being no need to rush into more purchases straight away.

Eventually a decent planetary ep in the 7 to 8 mm range would be my first port of call.

[brantuk]

In theory you get better light transmission through higher cost eyepieces than the cheaper ones. This is down to the higher quality coatings and better figured glass. It's a bit like the difference between a starter refractor telescope and a higher quality costlier model. You get more lenses in an eyepiece, better coatings with higher transmission levels, and better figured glass.

These all contribute to crisper clearer views and a range of magnifications, exit pupils, and view widths for different objects. Also, some eyepieces are better suited to one scope than another - eg slow f-ratio scopes are more tollerant of lower quality eyepieces, fast f-ratios demand higher quality pieces. Hth

[digital_davem]

Personal experience from a newbie with just a couple of observing sessions under the belt...

My second hand 1970s classic 3" refractor came with 3 EP:  a 4mm ortho, 6mm and 20mm Huygens all in 0.965 barrel sizes.

I've upgraded the eyepiece holder to 1.25" and purchased 12.5mm and 25mm Plossls. These are branded Antares and cost a princely £17.99  a piece.  

The difference between the stock EP and the new ones is ridiculous. The stock 20mm with a barlow screwed into it at least provides a view of the sky, without the barlow it vignettes. The other two serve no use at all, I might as well look through a toilet roll.  The Antares give lovely views that are much brighter, have a wider field of view and are sharp to the edges. 

I also acquired a Celestron Xcel 7mm 6 element EP this week. It's huge, like a camera lens.  It's also very usable compared to the short stock EPs which really don't work properly at all. It appears to have a wider field than my plossls despite the extra magnification. It also provides a comfortable viewing position, you don't have to screw it deep into your eye socket to see something. 

Quality-wise, at £70 new (I got mine for £35), you would expect it to be superior to the plossls but in the brief time I have tried it I didn't notice it to be so. This may simply be down to the challenges of focusing at 175x on a less than solid tripod or the seeing conditions at the times I've tried it.

Going from practice to theory, I've read that the benefits of top end EPs really kick in when you want well corrected wide fields with fast (low f-number scopes). My scope is f16.4 so very slow and in theory the view through the end of a coke bottle ought to be reasonable with this scope (which makes you wonder about the useless view through the stock EPs!).

I suspect that even cheap eyepieces supplied with modern scopes are going to be better than the junk that came with mine...

[Stub Mandrel]

Thanks, there are some really useful comments there. It seems to be more sensible to look at expanding my range a bit than replacing, until I have a better idea of my long-term interests.

Just a note. If 32mm and 40mm you mentioned are tele vue plossl, then they have the same field stop (27mm I think) and therefore the differences will be magnification and exit pupil, not the field of view.

The reason for having more eyepieces is to cover a wider range of targets. A way to define a useful range for your telescope is to consider the exit pupil. At least I found this very helpful when I bought my set.

These are SW ones. I went back and checked and it says "32 and 40mm: due to the 1.25" barrel size the 32 and 40mm eyepieces actually show the same area of sky so, for visual use, the 32mm is the better choice. The 40mm is however useful when a compact camera is positioned over the eyepiece for afocal photography." but the 32 does have a 50 degree FOV, so that would suggest it's worth me looking at the 32mm rather than the 40mm.

For a short F/L the UWA 6mm or 7mm seems a good idea - I imagine if its optimised for planetary viewing, then it might not be too hot at the edges, but that won'#t be a big issue.

Now to write my letter to Santa ;-)

[Putaendo Patrick]

Why upgrade eyepieces? The facetious answer might be 1). because manufacurers want us to, and 2). because manufacturers convince us that we want to.

This said, many inexpensive telescope kits have pretty good OTAs but are often let down by cheap eyepieces. This does allow the manufacturer to offer packages which are more price competitive - and I guess, in many cases, achieve a sale which they wouldn't otherwise if the price was 50 pounds higher. Thus with Huyens, Symmetric Ramsden and poorly-made Kelner eyepieces, an upgrade to relatively inexpensive Plossls will make a big difference.

With more expensive telescopes, especially those that come as OTA only, eyepieces are generally much better if and when supplied. Sometimes however they are not! Often better telescopes come with only one eyepiece, typically something like 25mm. Thus there is almost an immediate need to buy a higher-power EP for planetary observation.

Stub Mandrel: The question, it to me, is what do you want your EPs to do? Do you find it irritating that you can't see more sky - if so, maybe a 32mm. Do you want more magnification for the Moon or planets - perhaps a 7mm. If you're quite happy with the EPs you have, but want more range, maybe a reasonable quality x2 Barlow which would effectively give you 12.5 and 5mm.

If you ever go to a star party or club meeting, take notes on what other people are using. Maybe you decide that what you have is just as good (at least for you), or maybe (horror) you decide you just can't live without that $500 piece of exotic glass!

[Mak the Night]

I decided that I would coax the best performance out of my 102mm Mak before upgrading to a bigger SCT. So I replaced my perfectly good Celestron Plossls and a Kellner with TeleVues and acquired a TeleVue Powermate and 2x Barlow (I already possessed the TeleVue 3x Barlow). I was significantly impressed to purchase a TeleVue 19mm Panoptic as well. After that I went a bit mad and bought more wide angle eyepieces. The upshot is that I now have some very good quality range of magnifications and AFOV's for different conditions. I see eyepieces as tools of the trade, so to speak, more variety gives you more observing capabilities. Did I mention that I went a bit mad? lol

[ronin]

The reason is I suppose to gain better "quality" images and also very likely better comfort when using.

I do sometimes think that people wil upgrade because a new better sounding eyepiece has appeared, the number of ES82's sold when ES100's appeared was amazing.

Does the idea of looking down the centre of the eyepiece and not having any form of field stop (edge) appeal? If so then you will like the wide field eyepieces up at 82 and 100 degrees. That aspect does not bother me so I myself will likely not buy an ES 82 for that reason. However this may be something that appeals to you as a person, not necessarily optically. I hear ES have a new 92 degree eyepiece around somewhere.

Ultimately I think it comes down to just 2 optical aspects, sharpness and field. After that it is personal preference, and even field falls into this area = why does someone prefer a 100 field over a 60 degree field?

Comfort is a big aspect, another can be what you observe, go looking at a carbon star with an eyepiece that has coatings that transmit a bit more red then another then that is the better eyepiece for you. If you observe with an OIII filter often then really you want coatings the pass a bit more blue then red. The percentages are small but depending on the target one is better then the other, even if otherwise identical.

One aspect that I am guilty of is that I like having a set of eyepieces, I have the TV plossl's, the BST Explorers, the WO SWANS (still debating completing the Antares W70's). The BST's look nice as a complete set as do the others. I really seem to dislike having 1 or 2 different eyepieces from different ranges.

It comes down to you.

Ideally try something like the BST's against your eyepieces, but only try them if £50 each is acceptable. No use I think trying a £500 eyepiece as I suspect you would never buy a couple of them, I know I will not. It is ultimately all a balancing act. Are they the right price, do they produce the image, is the field OK, is the "colour" right, are the focal lengths right, do you like the appearance of them.

[Peter Drew]

In general, I think it is better to buy quality second hand eyepieces than new average eyepieces for the same outlay. 

[Charic]

......Why?........ for the perceived better image and field of view!

I own the 9mm  Revelation Astro [GSO]  and although its not a 10mm, it outperforms the standard supplied 10mm Sky-watcher  in image quality IMHO, and at £15, not a fortune.

I also own the 8mm Starguider, my original replacement for the supplied 10mm.  Its just so much better, for me! Better eye eye-relief, better field of view,  comfortable, a joy to use, but not a 10mm?

That said, the basic 'Super' 10mm  MA supplied with the scope does what it does, and unless some tells you different,  or you get the chance to look through someone else's identical scope to yours, albeit with a "better eyepiece", you will never know if you need to upgrade or not?

I don't own any other 10mm eyepiece to compare with, but my original 10mm hardly gets any focuser time.

I also don't need a 10mm?  A 6mm is better suited for my scope, to achieve a power of 200x, a 10mm would be better suited on the Sky-watcher Explorer as a medium power eyepiece,  Barlowed to get 200x if required.

Folk can and do make good the basic supplied eyepieces, and maybe that's all they need.  Finder-scope into target, wide-field with the 25mm then higher power with the 10mm, but that's your limit with the scope.

I work on the focal ratio of the scope so 6 is my starting point? 6mm provides 200x, 12mm is a happy medium, 24mm would do as a wide angle, and a 3mm would hardly get used except on the Moon for me? yet I have many more focal lengths. This only allows me to better frame the target. Whatever looks best on the night is the eyepiece to use. More eyepieces give me more scope (intended? )

[Charic]

........One aspect that I am guilty of is that I like having a set of eyepieces, I have the TV plossl's, the BST Explorers, the WO SWANS (still debating completing the Antares W70's). The BST's look nice as a complete set as do the others. I really seem to dislike having 1 or 2 different eyepieces from different ranges.

Snap!  OCD here too? 

The BST's will remain, but always wanted a Plossl set!

I cant use the 8mm TeleVue, so have discounted those, because I would eventually need the whole set?

I favour the Revelations, over my Meades at present, but really need to sit at a dark site, away from all light pollution, and with my old  eyes, try to better ascertain, and really study, which EP's I own are the best for me.

The Delos has arrived, and I'm eager to try and asses this eyepiece, and  If it works for me, then two more focal lengths may arrive, but as John said, seconds!  I could have easily bought 3 BST's and some,  for the price of the Delos.

John mentioned......." I've very rarely found a more expensive eyepiece showing anything that less expensive ones don't.......

For my  non-tracking f/6 scope, on axis, with a nominal 60° afov  that I'm used too, my field edge distortion is hardly noticeable,  if any ( I'll look again next time?)  but  f/6 its pretty comfortable at present, and with  a faster scope, I understand,  edge distortion, coma, should be more noticeable if your a visual user. If your  into astrophotography, the field of view needs to be sharp across the field, so premium priced EPs or additional correction  may be needed.

The point is, just about any eyepiece on axis, provided the scope is properly collimated, should work well, Its the extras you pay for!

[Stub Mandrel]

Thanks for some more interesting perspectives.

It seems I won't be wasting effort and money to try both shorter and longer FLs than I have already at a modest price point, new of S/H.

It sounds like these may give me significantly better viewing as well as a 'different' views, especially over the 10mm, in which case a better 9 or 10mm will make sense.

[Paul73]

Good thread.

I did a bit of a test at 8mm and the 18mm range.

8mm £20 - Generic Plossl vs £50 BST vs £250 Delos

18mm(ish) - MaxVision (16mm - £40) vs BCO (18mm - £50) vs Delos (17.3mm - £250)

Unsurprisingly, the Delos won both tests and represented a noticable improvement over the others. It showed fainter stars (just) than the others with the BCO a close second). For generalist eyepieces in a >f4.7 scope, I would wholeheartedly recommend either the BST range or the MaxVision. Although the MaxVisions don't come any shorter than 16mm and are getting hard to find.

Paul

[Mak the Night]

One aspect that I am guilty of is that I like having a set of eyepieces, I have the TV plossl's, the BST Explorers, the WO SWANS (still debating completing the Antares W70's). The BST's look nice as a complete set as do the others. I really seem to dislike having 1 or 2 different eyepieces from different ranges.

Oh yeah, I think my OCD comes into play a lot too. Which is probably why I bought all of the TV Plossls so as to have the set. I'll want all the 1.25" WO SWANS next ... maybe there's counselling for CESCS (Compulsive Eyepiece Set Collecting Syndrome)? lol

[John]

Oh yeah, I think my OCD comes into play a lot too. Which is probably why I bought all of the TV Plossls so as to have the set. I'll want all the 1.25" WO SWANS next ... maybe there's counselling for CESCS (Compulsive Eyepiece Set Collecting Syndrome)? lol

I used to call it being an "ocularholic"   

I'm still rather weak in this regard - despite being determined to "downsize" I've still managed to end up with 14 of the things ....

[glowjet]

When evaluating eye pieces, one further  point to take into account, is ones own personal vision quality. the younger generation contributors should have excellent vision and no problem. But as you age in years, so this does deteriorate to varying degrees from person to person,  no matter what quality eye piece is being used, the resolution may not appear to be as good to some, as what it is hyped up to be by other users.

For more years past than I can remember, I was a wearer of spectacles. It was not until my last visit to the opticians, some two years back, I was told to stop driving, ( I could not meet the DVLA Ministry standards ) that I realised that my eyesight had deteriorated so much. I was accepting that my ED scope observation with... TeleVue, Hyperions and Orthoscopics, was the best that could be delivered. How wrong I was, many, many months on, following operations on both eyes, the difference is unbelievable, both with resolution and clarity. 

I make this last point as eye sight deterioration can creep up on you unexpected and you may not evaluate the reasonable priced, to expensive eyepieces, to perform as well as many have said they do. This does not relate to the Huygens, Super Ramsden and some others that are supplied as standard, when purchasing first scopes, the kindest think to say about them is, they are not the sharpest knives in the drawer, but useful never the less to get most started with their observations

[Piero]

Thanks, there are some really useful comments there. It seems to be more sensible to look at expanding my range a bit than replacing, until I have a better idea of my long-term interests.

These are SW ones. I went back and checked and it says "32 and 40mm: due to the 1.25" barrel size the 32 and 40mm eyepieces actually show the same area of sky so, for visual use, the 32mm is the better choice. The 40mm is however useful when a compact camera is positioned over the eyepiece for afocal photography." but the 32 does have a 50 degree FOV, so that would suggest it's worth me looking at the 32mm rather than the 40mm.

For a short F/L the UWA 6mm or 7mm seems a good idea - I imagine if its optimised for planetary viewing, then it might not be too hot at the edges, but that won'#t be a big issue.

If I am not wrong your 150PL is F8. Therefore a 32mm would give you an exit pupil of 4mm. I don't really think you want something larger if you observe from a moderately light polluted sky. In addition, if one day you plan to replace your 150mm or add, let's say a 250mm (dobson), this will likely have a shorter focal ratio. Hence the 32mm will be more usable than the 40mm.

Some time ago I wrote a mini guide: 

http://stargazerslounge.com/topic/251506-a-guide-for-choosing-a-sensible-eyepiece-collection-using-the-exit-pupil/

Only an indication of course, but it might be useful, as I suspect you (like me) want to have a minimal set of eyepieces and maximise their use. 

All the best with your purchase(s), 

Piero

[John]

This might be a little controversial but one train of thought (which I tend to agree with) is that the eyepiece is half the optical system. The image we see will be as good as the weakest link in the optical train allows.

[Stub Mandrel]

> many months on, following operations on both eyes, the difference is unbelievable, both with resolution and clarity

I trust that it's brought benefits in other areas of life as well!

[Stub Mandrel]

This might be a little controversial but one train of thought (which I tend to agree with) is that the eyepiece is half the optical system. The image we see will be as good as the weakest link in the optical train allows.

It occurred to me as well, also thinking about what sort of skies I can easily access.

[DRT]

I used to call it being an "ocularholic" 

Hi, my name is Derek and I am an...