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My eyepieces - opinions welcome


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Hey everyone :(.

I have studied the stickied topic on the correct eyepieces based on your telescope and would welcome any thoughts to my set.

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Warthog mentions that if an EP has SP on it, don't even think about keeping it. Is this the 'SUPER' eyepieces that I own? the 10mm and 20mm both feel cheap and came with my starting telescope.

My telescope is an 8" newtonian so that is 200mm aperture. A focal length of 1000mm divided by that gives me 5. F5 is the focal ratio of my scope right?

Therefore the highest power eyepiece I could use is 4mm. This is one of the reasons I got the 4mm EP, however it is chronic and I am not sure why anyone would want to own, let alone use this eyepiece! So Warhog recommends an EP of 1.5 times the focal ratio, ie 7.5mm.

I also have what feels like a cheap Barlow. It came with my skywatcher telescope. Base on what I own now, do you think I should invest in a higher quality one, or is it not worth it?

Then exit pupil comes into play and I have even more questions! An eyepiece of 5 times your focal ratio also gives you a 5mm exit pupil which is pretty much the max, without wasting the light of your image right? So on my telescope I shouldn't be using eyepieces that are higher than about 25mm, making my 40mm also redundant...

Could I get any advice on my final thought which was to get a new set for my f/5 scope. 2x Barlow, 8, 18, and 25mm?

I have so many questions I feel bad asking them, I hope this is the right section for my topic.

Cheers

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Yes, a 200mm aperture scope with 1000mm focal length is an F5 scope. This is great for wide-field views (and if the mirror is good it can still give good planetary views. Unfortunately this short focal ratio will test your lower-quality eyepieces, especially the longer focal length ones with wide fields.

The small f-ratio will mean objects in the outer-part of the field will be suffer from coma-distortion, worsening nearer the edge. For low-power views that are sharp nearer the edge requires better-quality eyepieces as these are made to compensate for coma.

I would recommend you buy a couple of these more expensive eyepieces rather than a set, which tend to be of lower quality. I wouldn't bother with a abrlow for now as it will only worsen the views when used with lower quality eyepieces. Others will recommend which ones you could buy, depending on your budget.

Re: the 4mm eyepiece - there may be other factors causing the poor views such as collimation, temperature acclimatisation of the main mirror, sky quality etc.

How old are you, as our maximum exit pupil tnds to get smaller with age (about 7mm when young, 5mm when late-middle age or older) ?

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Hi Adz

Don't feel bad about asking questions. Thats what this forum is for. There are loads of people to help you.

Regarding your set its good for a beginner but if the hobby takes off you will find yourself wanting better and more expensive :( eeypieces. The silvertop 20mm plossl is a good eyepiece and one to keep. Regarding the others, I imagine you will want to ditch them sometime in the future but as a starting point they will do the job for now. It all depends on your budget because you can spend silly money. More expensive eyepieces will provide clearer wider views that are well corrected. You will find though that you will have to keep spending more and more for deminishing returns.

Do you wear glasses? If so you want eyepieces with around 20mm of eye relief such as the TMB clones / radians / pentax XW/ Vixen LVW and others.

I would say that the TeleVue Plossls are a good and reletively cheap way to start. If / when you decide to move on you can sell them for a high % of their original cost if you want to upgrade. Also look to buy second hand, that way if you decide there not for you you can often sell them on for what you paid.

Finally read the eyepiece guide which is a sticky topic but I have found that you can push much further than the 133X suggested.

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You're right, the 4mm and 40mm EPs are of limited use. 4mm is too high for an 8" scope: you'd get more use out of a good 8mm plossl (e.g. TeleVue). With the 40mm you've got wasted light because of the exit pupil size but it still might have use as a low-power finding eyepiece.

You suggest 8,18,25mm and 2X Barlow. I don't see why you'd need 6 magnifications, nor why you'd want to get two powers so close to the 20mm you've already got. Keep it simple and well spaced: low, medium, high.

I have to disagree with the advice that anything marked SP ("super plossl") is not worth keeping, though it may well end up in your spares box eventually as you upgrade. For now I'd say stick with which ever 20mm you prefer and for lowest power either invest in a good 32mm plossl (e.g. TeleVue) or use your 40mm EP. For high power get a TeleVue 8mm plossl or maybe a TMB Planetary. Barlows, IMHO, are a waste of money. Cheap ones make the view bigger but worse, expensive ones make the view bigger but no better.

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I think Warthog writes to stay clear of 'H' (Huygens) and 'SR' (Ramsden I think) marked eyepieces because they tend to be inferior. I might have missed something about SP of course.

The 'Super' eyepieces you have are 'RKE' (a modification of the Kellner design) and not plossls despite the 'Super' title.

I think they are useable despite my 25mm version shows some funny stars at the edges.

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For an f/5 scope you need good eyepieces. Now a TV plossl may (only may) be OK, but they start at 8mm so would give 125x magnification.

I suspect that the next TV eyepiece up may be a better option but they are around £160 a piece, Radians I think but could be wrong.

As to a 4mm eyepiece, go visit Cloudy Nights, look through the Eyepiece section and locate the thread about What use is a 4mm eyepiece? Gives a good idea as to what to do with a 4mm eyepiece.:(:eek::) (Subtle hint looking through one isn't high on the options)

Next, you have bought a scope that is for collecting light, and giving wide views of the sky. Note the absence of pushing the magnification to the limit.

f/5 on any scope is to be considered with care, reflector or refractor. They are to an extent operating at the limit of what is achievable on amateur scopes. That means high maintenance. High cost.

I have noticed that the refractors are backing off of f/5 and going to a much more useable f/7 now.

An 8mm sounds OK, 25mm also OK but then get something at say 12mm.

The 25mm to make locating easy, the 12mm and 8mm for some magnification.

The TV plossl's come in 8mm, 11mm and I guess a 25mm (don't have one and haven't looked). Slight drawback is £75 a piece.

The GSO plossl's have a decent name and are less, think Modern Astronomy sell them.

Ask on the forum about peoples opinion. Better still borrow one the try.

Ask what eyepieces others with the 200P use and how they find them.

Forget barlows.

Have you stuck a location down?

As if you happened to be a few mile from me you could try one or two of mine. Helps to know.

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Regarding 4mm eyepieces. I don't know what 4mm's are like generally but I have a William Optics 4mm Uwan which is marvellous, very comfortable to use with good eye-relief (about 12mm I think) and good contrast (& a v. wide field of view). Excellent on the moon in both my scopes (F 5.3 newt & F5.9 refractor).

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Thank you very much for the feedback everyone, it is always worth mentioning something on this forum as I know many good things can come of it!

From learning the nature of my f5 scope, I see that it is important to use EPs of a reliable quality. I don't have a problem shelling out a bit of dosh if it really is an EP that I will have for a long time with good results :(

In regards to my exit pupil, I am 22yrs so I am sure mine is a bit wider than 5mm. But I nearly always observe with my dad who is 50yrs+ so I am willing to buy EPs based on his stats!

I had a feeling that the silver top plossl was a good one so its nice to have been confirmed! What does the multi-coating on it mean/do?

I see that you own many televues Kef and you regard them strongly. After reading up on them perhaps this quote from Astronomics site is something to bear in mind for me

'The TeleVue 8mm, 11mm, and 25mm Plössls were top-rated in a recent test report of 31 eyepieces in Sky & Telescope magazine.'

Acey you asked why and where I got those EP sizes idea, it was from Warthogs threat, its actually what he recommends. But I think I would rather not have a barlow anyway for more than one reason. Your advice really made it clear why they are perhaps what I am looking for in a set atm.

I want to make it clear that I would prefer optical quality over magnification any day (a skill that every newcomer to astronomy should realise). I didn't buy my telescope to get close, just to get a brighter M31 and more detail on Jupiter for example.

I have just realised a major point that should be included in my bought of questions. I do have the option for 2" EP's. Presumably they give greater views, optically, FOV or both? Can you also get these Televue Plossl with a preferred 2" piece?

Finally thanks again for all the help, for a student like myself I really like to make double sure of what I am going to buy and why beforehand! :)

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.... What does the multi-coating on it mean/do?.....

.....I have just realised a major point that should be included in my bought of questions. I do have the option for 2" EP's. Presumably they give greater views, optically, FOV or both? Can you also get these Tele Vue Plossl with a preferred 2" piece?....

My understanding is that multi-coatings minimise light loss at air-to-glass surfaces. Multi-coated usually means that the top of the eye lens (the lens you look into) and bottom surface of the field lens (the last lens in the eyepiece) are multi-coated. Fully multi-coated usually means that all air-to-glass surfaces in the eyepiece are multi-coated which is a little better in terms of a specification.

The primary advantage of 2" eyepieces is that they provide a larger field of view so they are mostly found in longer focal lengths where this is an advantage - ie: 20mm or longer. They don't provide better quality / sharper views than the 1.25" eyepieces. There is a 2" Tele Vue Plossl and it's focal length is 55mm but you really need an F/10 scope to make use of it so it's rather specialised. In most scopes a 32mm or 40mm 2" eyepiece is the most useful focal length in the 2" fitting.

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Hi Adz

I'm looking after my son all day today but when the mrs gets back later I will give you the lowdown on what you should be looking to get for a variety of budgets. This is my own personal opinion and also based on what I have read from others experiences but it should be a fun read and open to alot of discussion. :(

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I didn't buy my telescope to get close, just to get a brighter M31 and more detail on Jupiter for example.

So you're looking for contrast: full multi-coating and good internal baffling help this. You'll get that with a TV plossl. First time I looked at Jupiter through the 8mm my jaw dropped, having previously only seen it through the plossl that came with my scope. In addition to the ones you mention, the 32mm TV plossl is widely considered a classic. I love mine and have used it on every scope I've owned, from 80mm to 12".

I have a 4mm Nirvana eyepiece and sometimes use it on the 12" (for deep sky), but doubt I would ever have got any use out of it on an 8". I did try a Barlowed 8mm on my 8" and saw a big blurry Jupiter race across the field of view looking like it was in a fish tank.

You can pay more for other TeleVue ranges and what you'll get is wider field (with 1.25" or 2" EPs), but otherwise much the same performance that you'd get with their 1.25" plossls. (I've seen various reviews saying the Radians have poorer contrast than the Plossls and I've never been tempted by them).

One thing I'd say: the TV 8mm plossl is a small bit of glass with not a lot of eye relief. I managed fine with it on my 8" f6 but it's not everybody's cup of tea. The 11mm is much more comfortable: when I first got my 12" f4.9 the 11mm quickly became my favourite. For higher power on the 12" I went with a TMB Planetary 6mm, which is a wide-angle type (making it easier to track with a dob). Putting the TMB and TV side by side (and allowing for the different focal lengths), they seemed pretty much equal, but for me the TV still had the edge.

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By the way the standard Barlow with your scope is probably the Skywatcher de luxe version which is not a bad Barlow, it scored well in a Sky at Night test. As far as I know the de luxe can be differentiated from the standard one by the fact it's threaded at the eyepiece end of the barrow.

I am going to be different on EP advice and make two suggestions,

(1) get out with other astronomers and take a look at their EPs if at all possible.

(2) don't get hung up on the old fast scopes need super quality argument, technically that may well be true but I have a range of EPs going from the cheap and cheerful to one upmarket EP, the most used EPs in my collection are relatively inexpensive ones, yes they produce slight aberrations but little that I cant live with. Below F5 it's much harder but F5 is on the cusp and although some of the cheaper EPs will show astigamatism on the extreme outer edge of the view for everything I have looked at to date it doesn't matter because the core or the view is fine and that's what I tend to be looking at.

The best is always the best but don't break the bank expecting a quantum difference because after the £100 mark you are buying improvements in very tiny percentages.

On the whole I'd really recommend getting a view first because what one user likes/can live with can be very different to someone else.

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I totally agree with Astro-Baby on this. Do what you can to try and see other user's equipment first if at all possible. Also, there's a big used market in the UK for eyepieces so 1) you can buy gear which has almost certainly been cared for well 2) it will be at much reduced prices compared with new 3) if you buy decent quality you can sell it again and just lose the postage.

I own a lot of good to excellent eyepieces and in all honesty they are definitely better than really cheap ones but the difference is NOT eg 10x better than something costing 10x less.

Take your time and buy to fit needs rather than to create a shiny collection (OK I am a bad example as that's what I have done in a way - but there's reasons I did).

If you had a gun to my head and asked me what you should do, I'd recommend the following (I am assuming that as you have mentioned no problems using the 10mm EP that you don't wear glasses to observe?):

For now - cost £0 :

  • Retain the silver 20mm and the 40mm
  • Also the Barlow, which I agree is probably reasonable assuming it's the one A-B describes with the threaded top - it's really not bad.
  • Only use the 20mm in the barlow.
  • This gives you a wide field 40mm (25x), a medium field 20mm (50x) and with the 20mm and barlow a reasonable 10mm (100x).
  • You have the others as back-ups but I'd put them in a box and I bet you'll never use them.

In the longer term:

  • Consider a 32mm (for your wide field 31X) as this will have a better exit pupil ratio than the 40mm. I'd recommend a TV Plossl.
  • Also consider a 15mm TV Plossl. This will set well with your other eyepieces and give 67x and 134x when barlowed alternatively a 12.5mm Baader Genuine Ortho would give 80x and 160x when barlowed. The eye relief on both of these is far better than the 11mm TV Plossl (I have all three). The quality of them all is superb.

One thing which will enhance your ability to find things very well is not an eyepiece but a Telrad finder. Given what you have, I'd personally say this is more important than other eyepieces at this stage.

Whatever you do, enjoy the show!

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Okay Adz here is my roundup which I have split into low, medium and high cost against low, medium and high power. This is based on my own experiences and what I have read/heard from others.

This is what I would buy depending on my budget. Others will disagree and have a different point of view so remember that this is my own personal opinion. One thing to remember is that as focal lengths go up so does the general price. I have reflected this in my budget calculations.

High Power (HP) – 12mm and below

When looking at high powers I think the FoV is not as important as the light transmission of the optics. It is also important to have a bigger range of eyepieces to match the seeing conditions.

HP – Low Budget (below £50)

For me it is between the TMB clone - Radian like performance (20mm eye relief, 60 degree FoV) at a fraction of the cost. Alternatively if you can handle the eye relief the Japanese Circle T orthos will probably provide a slightly sharper view at the expense of FoV (40 degrees) and eye relief.

HP – Medium Budget (£50 to £100)

If you can handle the eye relief then this has to go to the TeleVue (TV) plossls and Baader Genuine Orthos (BGO’s). As an added bonus they nicely complement each other due to the focal lengths available.

HP – High Budget (above £100)

There are lots of contenders here which makes things confusing so it depends on what you really want.

If you want decent eye relief and a 100 degree FoV (to frame planets in a sea of stars) then the ethos is for you.

If you want to dial into the seeing and have multiple eyepieces in one then the Nagler zoom is exceptional.

If you want near to the maximum optical performance, long eye relief and a 70 degree Fov then the Pentax XW is the one.

If you want the absolute ultimate in optical performance at the expense of eye relief and FoV then the Pentax XO, TMB supermonos (discontinued) and the ZAO orthoscopics (discontinued) will hit the spot.

P.S. Honourable mention to the Skywatcher Nirvana / William Optics UWAN which are pretty much the same thing.

Meduim Power (MP) 13mm to 20mm

When looking at medium powers I think the FoV is more important so you can frame deep sky objects (DSO’s) properly. You really only need 1 eyepiece in this range.

MP – Low Budget (below £100)

Televue plossls will provide a great view but at the expense of FoV. However at this price it is hard to disagree with the quality on offer.

MP– Medium Budget (£100 to £250)

I would go with the Skywatcher Nirvana / William Optics UWAN for the 82 degree FoV. If you can push the budget then the Nagler (also 82 degree FoV) will offer you slightly better corrected views but the difference is minimal I am led to believe.

MP– High Budget (above £250)

The TV ethos is king here. Especially so because it will frame objects nicley whilst providing high magnification. If you were to invest in an ethos this is the area to do it.

Low Power (LP) 20mm and above

When looking at high powers FoV is important. Again you only need to buy 1 to 2 eyepieces in this range.

LP – Low Budget (below £150)

This has to go to the Meade 5000 SWA range with the discounted prices on offer at the moment.

LP– Medium Budget (£150 to £300)

The Televue Panoptic is a strong contender here (imagine a better corrected Meade 5000 SWA) but I personally would go for the Skywatcher Nirvana / William Optics UWAN for the bigger 82 degree FoV.

LP– High Budget (above £300)

The Naglers are the masters here but if money is no object then the ethos 21mm is a very special eyepiece with a near £700 price tag to match.

Okay that’s it. Quite a long post! It has been said before that you should try them out first and if you can you should. Just remember that I said that more expensive eyepieces will provide clearer wider views that are well corrected but you will find that you will have to keep spending more and more for diminishing returns. For me personally though I thought it was worth it because these to me are for life.

Finally just to repeat a point I made before is that you may want to just keep your current set together for the time being to give you time to decide whether you want to actually upgrade and take the hobby further. Once you get the bug its hard to stop! :(

Just waiting to be slaughtered now!

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Meduim Power (MP) 13mm to 20mm

When looking at medium powers I think the FoV is more important so you can frame deep sky objects (DSO’s) properly. You really only need 1 eyepiece in this range.

MP – Low Budget (below £100)

Televue plossls will provide a great view but at the expense of FoV. However at this price it is hard to disagree with the quality on offer.

The Meade 5000 SWA 16mm can be added here too. It's available for £79, which makes it a major contender. :(

Looks a great list to me Kef

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I like the William optics SPL 6mm. It's very comfortable to use with good eye-relief, very contrasty and sharp, plus 55 degree field of view. I think the 12.5mm SPL is probably just as good too. They sell for around £70 each, new.

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The Meade 5000 SWA 16mm can be added here too. It's available for £79, which makes it a major contender. :(

Looks a great list to me Kef

Cheers Russ. It took me ages to write that one!

Yep at £79 the meade is an absolute steal!

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I like the William optics SPL 6mm. It's very comfortable to use with good eye-relief, very contrasty and sharp, plus 55 degree field of view. I think the 12.5mm SPL is probably just as good too. They sell for around £70 each, new.

I've never tried these nor heard much about them to be honest.

Regarding where you can buy the meade from - See this thread

http://stargazerslounge.com/equipment-discussion/121910-meade-5000-swa.html

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What an encyclopedia of knowledge I have before me, thank you!

I think that maybe some people have been concentrating on this, rather than a boring day at the office? Hmm maybe ha ha.

The first thing is that I am sure I don't have the nice Skywatcher barlow, it doesn't have a screw at either end and feels cheap. However I am still of the opinion that I don't need a new one.

Before I buy anything I will be meeting up with Capricorn at our local club as he has kindly offered to let me try out some of his EPs.

Anyways, I will continue to scour astrobuyandsell to get an idea of what is out there and how much it should cost. You are right about not needing to collect a shiny collection of EPs but I do want to have a set of high quality ones that I can rely on, at the moment I feel the views I am getting through my telescope are of a slightly disapointing quality and this is down to my current shoddy EPs.

Sorry I didn't get back to you about the glasses question, neither my father or me wear them so a long eye relief is not always needed. The telrad suggestion is interesting, I had never heard of these before, are they much better than a finderscope?

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Okay so onto the EP discussion! This is all good for the future, when I have sold a guitar :p

I was set on the Televue Plossls for their balance of affordability and improved quality over what I currently own.

But now with the discussion about these Meade things you guys are starting to loose me if I am honest! :(

So I looked up Meade EPs on first light optics and then saw more Plossls and I feel like I am ending up with more questions again :)

oh and one final thing, what is the purpose of the screw off bit on my 40mm?

IMG_7501.jpg

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The telrad suggestion is interesting, I had never heard of these before, are they much better than a finderscope?

Re the Telrad, this is a different kind of finder. It's basically a nil magnification target superimposed on the sky. you can quickly line up the scope using both eyes - a synch. I then use my optical finder scope to home in on the target and it's usually in the eyepiece.

good luck with you choices! :(

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So I looked up Meade EPs on first light optics and then saw more Plossls and I feel like I am ending up with more questions again :(

the meade 5000 series come in 3 different flavours.

The modified plossl has a 60 degree FoV (coloured red)

The SWA has a 70 degree FoV as is mainly what was discussed above (coloured green)

The UWA has a 82 degree FoV (coloured blue)

Hope this makes sense. The TV plossls are a great way to start by the way.

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I own a telrad and as a relative newcomer I can honestly say that it is probably the best £35 that I have spent. It is so much easier to locate objects using this. I never use my finderscope now. I would be as well taking it off. My scope is also an F5. My 32 mm skywatcher SP plossl which I bought from FLO is excellent. It also works really well with the celstron barlow that I have. I also have a 6.3mm skywatcher SP plossl which I find difficult at times. This does not work well with the barlow. Complete waste of time. I have also been thinking though of moving up and purchasing better EPs. I will be using kef9's list,. Thanks!

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