Eye piece conundrum

[Tim Armes]

Hi all,

My set up is currently very simple:

8" Meade Lightbridge

16mm Meade SWA eyepiece

I'd like to get a higher magnification eyepiece to take me up to about 250x, so approximately 5mm. I've been reading lots, but to be honest I'm struggling to know what do get.

I'd rather spend more now than buy twice later, but on the other hand the differences in price are so extreme that I doubtful that my newbie eye can really justify some of the very high cost EPs.

Also, I don't yet have a feeling for the AFOV that I should get. Some people don't like the larger fields of view, others love it. I also get the impression that the wide APOVs reduce image quality - is this true?

Following on from the above, will a 250x ever be useful for DSOs (as opposed to planets), and if so will a greater APOV be useful for this use case?

The reviews I've read tend to confuse me more than anything else. For example, I've read some great reviews for the Meade 4.7 and 5.5, and I've also read comments from people who really can't stand them, claiming that the IQ is awful.

Similarly, the 5mm Radian offers a large AFOV, but it seems to get extremely mixed reviews. The coveted Pentax 5mm XO is extremely expensive, and I don't really know how the limited AFOV will limit my use of it, or if it's ever worthwhile for a beginner.

So, any help would be appreciated. If you make any suggestions then please list the full name, because I'm only just starting to figure out the various lines and companies that produce them.

Thanks,

Tim

[John]

Hi Tim,

As the range of choice is so very wide (as you know !) having a budget can sometimes help narrow things down a bit.

A wider angle of view is helpful with an undriven scope like a dobsonian - personally I use ultra wide angles but the price is also "ultra" !. You could do worse than a Hyperion 5mm which will work pretty well in your F/6 scope and has a medium-wide field of view (68 degrees). They cost around £100 new I think.

250x would be good for planets on nights of good seeing, less useful for deep sky objects. You might find an 8mm or 7mm eyepiece gets more use to be honest. Ideally a 7mm and a 5mm of course !.

[Tim Armes]

Hi Tim,

As the range of choice is so very wide (as you know !) having a budget can sometimes help narrow things down a bit.

I don't have a budget - I prefer to save if necessary than to be disappointed with a buy.

Of course, that's no reason to buy the most expensive eyepiece just for the sake of it either. A compromise would be best.

A wider angle of view is helpful with an undriven scope like a dobsonian - personally I use ultra wide angles but the price is also "ultra" !.

Good point. Well that narrows it down a little.

You could do worse than a Hyperion 5mm which will work pretty well in your F/6 scope and has a medium-wide field of view (68 degrees). They cost around £100 new I think.

250x would be good for planets on nights of good seeing, less useful for deep sky objects. You might find an 8mm or 7mm eyepiece gets more use to be honest. Ideally a 7mm and a 5mm of course !.

So 160x to 180x is useful for some DSOs? That's good to know. Perhaps then that'd be a better first buy since I'd get more use out of it than the 5mm.... (since there are only a couple of planets to capture my attention).

[John]

...So 160x to 180x is useful for some DSOs? That's good to know...

Well, more useful than 250x would be although your 16mm SWA plus something lower power would be better DSO tools.

A good range for your scope would be a 32mm 2" eyepiece for low power, your 16mm SWA for medium power, then 9mm, 7mm and a 5mm for progressively higher powers.

[Tim Armes]

Well, more useful than 250x would be although your 16mm SWA plus something lower power would be better DSO tools.

A good range for your scope would be a 32mm 2" eyepiece for low power, your 16mm SWA for medium power, then 9mm, 7mm and a 5mm for progressively higher powers.

The 9mm, 7mm and 5mm would give magnifications of 135x, 175x and 240x respectively. Would you mind giving me a few examples of objects that would be best viewed with those magnifications? That would really help me prioritise the buying order.

Is there really enough difference between 135 and 175 to be useful?

Regards,

Tim

[John]

Tim,

It's more a matter of having a range of powers to suit the prevailing observing conditions than matching particular objects to specific magnifications. Under mediocre conditions 135x or 175x could be as much magnification as it's worth using, even on the planets, the moon and binary stars. When the seeing is good you can observe the same things at 240x or even higher.

At the other end of the scale, some deep sky objects like M31 (the Andromeda galaxy) are very large and low power and a wide field of view is required. But sometimes it's nice to be able to view just a section of a large object at higher power for example the Trapezium region of M42, the Orion Nebula.

I guess I'm just trying to illustrate why having a range of eyepieces is desirable

[Demonperformer]

I have the Pentax XW5, which is a nice eyepiece, but (as has already been suggested) conditions need to be really good to make it worthwhile. I would suggest something more in the middle (8-10mm) would get more use. At least, I would for a UK observer. I'm not really sure what your conditions are like in France.

[Damo636]

Hi Tim. The 8mm Hyperion is a really good eyepiece. I use it for planetary observation as well as double stars and globular clusters. As John states it performs really well at f6. Baader sell a 14mm and a 28mm fine tuning ring to alter the focal length of the Hyperion. They cost around £8 each and effectively give you an additional 6mm, 5mm and 4.3 mm focal lengths without degrading the quality of image.

[swamp thing]

I would suggest something more in the middle (8-10mm) would get more use. .

So would I.

You can always Barlow a Good eyepiece in this range to get a really high power combo for the occasional nights that will permit it.

Regards Steve

[Capricorn]

If you were looking at the 8mm arena I would say consider one of the TV plossl's.

They are always reckoned to be good, should be fine on an f/6 scope, believe they are pretty good down to f/4.

Standard plossl field of view, ~52 deg.

They start at about £80 so not bad on budget. They come in 8mm, 11mm, 15mm, 20mm, 25mm so fair selection. If you wanted greater magnification then perhaps a 5mm Radian (think that is the next one up) at £180 will do that. Would depend if you wanted to spend £180 on one eyepiece.

Check the used market as TV plossl's come up at reasonable intervals. May be a less expensive way to find out.

[haitch]

Just to throw something in the mix...

How about getting a good barlow now to give 8mm on the 16mm and then look for something like a 10mm to 12mm to give 5mm to 6mm in the barlow? More gaps filled and 12mm is a useful f/l IMO.

[Tim Armes]

Just to throw something in the mix...

How about getting a good barlow now to give 8mm on the 16mm and then look for something like a 10mm to 12mm to give 5mm to 6mm in the barlow? More gaps filled and 12mm is a useful f/l IMO.

Hi,

Hmm, interesting idea.

The idea of a barlow lens hasn't really crossed my mind because 2x extenders for cameras are of dubious optical compared to a lens designed for twice the focal length.

In the telescope world, however, does a good barlow have a noticably detrimental effect on the optical quality?

Are there any good ones to be recommended?

I saw the extenders on the Meade site, which claim:

"The Series 5000 TeleXtenders are the finest power multipliers sold today. Their advanced 4 element design delivers a flatter field-of-view with sharper edges than even the best 3 element apochromatic Barlows. They feature fully multi-coated lenses with no color fringing."

Is this just marketing hype, or are they decent?

Tim

[Tim Armes]

Tim,

I guess I'm just trying to illustrate why having a range of eyepieces is desirable

Thanks, point taken.

Sounds like I'd be better with a range in a reasonable price range than just one of two high end ones.

I would suggest something more in the middle (8-10mm) would get more use. At least, I would for a UK observer. I'm not really sure what your conditions are like in France.

Several of you have suggested this, so I'll take your advise.

So, which 8mm EPs are to be recommended. I think I'd prefer a wide FOV since the dob isn't motorised.

Or, as suggested elsewhere, perhaps a good Barlow for my 16mm is a better option?

Regards,

Tim

[Rob Severn]

How about one of the less expensive eyepiece sets ? Lots of different sizes to play about with. I used to have the Revelation set for my LX90 , they performed very well.

[Tim Armes]

How about one of the less expensive eyepiece sets ? Lots of different sizes to play about with. I used to have the Revelation set for my LX90 , they performed very well.

Well, I'm certainly happy to spend less to get decent kit

On the other hand, I'd rather invest in something that I'll be happy with in the long term.

How does the kit you suggest compare to the higher end ones? Is it a case of getting 90% of the performance for 50% of the price, or is the difference in quality more pronounced?

I'm looking at the Barlow option - most people state that the reduction in quality is negligible, so that's reassuring.

Tim

[brantuk]

I use 5mm and 8mm Radians and Hyperions in my dob with planets. They'd work well in yours too but the 5mm tends not to be used as much due to seeing. A 28mm Uwan would be great in your scope for dso's. No point ramping up the magnification on dso's cos they do tend to be very wide - I find zooming in dso's to be not not as satisfactory as exploring the whole object with the clarity of a good quality wide eyepiece. Go second hand to make big savings

[Tim Armes]

I use 5mm and 8mm Radians and Hyperions in my dob with planets. They'd work well in yours too but the 5mm tends not to be used as much due to seeing. A 28mm Uwan would be great in your scope for dso's. No point ramping up the magnification on dso's cos they do tend to be very wide - I find zooming in dso's to be not not as satisfactory as exploring the whole object with the clarity of a good quality wide eyepiece. Go second hand to make big savings

The overwhelming advice seems to be to get an 8mm and a wide angle of about 28-32mm, so that's my plan. I have a couple of options:

1) Barlow + 10mm + 30mm, giving me 30mm, 16mm, 15mm, 10mm, 8mm and 5mm options.

2) 8mm + 30mm, giving me 30mm, 16mm and 8mm.

Options two is less expensive (no Barlow). On the other hand, adding a Barlow later would have minimal benefit on that collection.

I'm trying to find second hand, but don't really know where to look.

Tim

[brantuk]

When you get to 50 posts and one full months membership of SGL you'll be able to see the For Sale section. Meanwhile Asto Buy/Sell is a good source for astro items. These kind of eye pieces come up quite frequently in both

[Tim Armes]

When you get to 50 posts and one full months membership of SGL you'll be able to see the For Sale section. Meanwhile Asto Buy/Sell is a good source for astro items. These kind of eye pieces come up quite frequently in both

Well, I shaln't be waiting for access here. I had the impression that Astromart was more US based - is this not the case?

Tim

P.S. Not being able to post in Buy/Sell seems fair enough, not being able to look, on the other hand, appears to penalize the members that do have access and can't sell to newcomers.

[Rob Severn]

Well, I'm certainly happy to spend less to get decent kit

On the other hand, I'd rather invest in something that I'll be happy with in the long term.

How does the kit you suggest compare to the higher end ones? Is it a case of getting 90% of the performance for 50% of the price, or is the difference in quality more pronounced?

I'm looking at the Barlow option - most people state that the reduction in quality is negligible, so that's reassuring.

Tim

Et....viola

One from this very forum

http://stargazerslounge.com/equipment-reviews/46378-revelation-eyepiece-set-99-a.html

And one from Sky at Night

http://www.skyatnightmagazine.com/review/eye-pieces/revelation-photo-visual-eyepiece-and-filter-kit

Edit: the kit has now been changed to a photo/visual kit incuding barlow and T mounts if I remember rightly.

[Scosmico]

Hyperion 8mm is quite good. But I never used the fine tune ring.

[RikM]

I use a Meade 4000 8.8mm UWA and that's very nice for planets and smaller DSO's and together with a 13mm Hyperion, these are my two most used EP's. I have a Vixen LV 30mm / 60° for low power.

My next EP will probably be a 6mm TMB II or 5mm Hyperion, still undecided.

[haitch]

Well, I shaln't be waiting for access here. I had the impression that Astromart was more US based - is this not the case?

Tim

P.S. Not being able to post in Buy/Sell seems fair enough, not being able to look, on the other hand, appears to penalize the members that do have access and can't sell to newcomers.

This is astro buy sell... U.K. Astronomy Buy & Sell

It is for very good reason that the rules were introduced. If they want to sell to people other than members who meet the criteria they can go to the above anyhow.

[Moonshane]

I am very fortunate to have eyepieces ranging from my 6-3mm Nagler zoom to a 26mm Nagler and in fields of view from 100 degree Ethos to 40 degree Baader Genuine Orthos. I love them all and have carefully built this collection over time to match the current scopes I have (6" f11 and 16" f4 dobsonians - both 1600mm focal length) and also any future scopes. I may not have to buy another eyepiece again or that's the plan.

for planets my most productive eyepiece is my 9mm BGO = 178x and this would equate to a 7mm eyepiece in your scope. generally this gives a good image of all planets although I can sometimes push it a little more.

on the moon and doubles I can often use 250x and even higher so I use the Nagler zoom. I don't wear glasses to observe so tight eye relief is not a problem to me.

for some DSOs like planetary nebulae you do need more power so perhaps treat these like double stars.

having a driven mount (equatorial platform) helps with the narrow field but it's not essential as long as your axes are well adjusted etc.

if using a non driven scope I have a 10mm and 8mm Radian which are excellent and have a wider field.

I took the view a while ago that I need close eyepieces at the higher mag end so have 26mm Nagler, 18mm BGO, 15mm TV Plossl, 13mm Ethos, 12.5mm BGO, 11mm TV Plossl, 10mm Radian, 9mm BGO, 8mm Radian, 7mm BGO and 6-3mm Nagler zoom. I really do use them all too. This really covers any sort of seeing and magnification required. Take your time and buy eyepieces over a period, sell ones you don't get on with and buy others. There's no major rush.

I take the view that if you need more power then field of view becomes less important as long as you have a driven mount.

for you, my recommendation would be either a 9mm BGO or a 10/8mm Radian. Any of these can be barlowed on those 'special' nights of seeing if you eventually get a barlow (I don't like them personally). You can buy both used for about £50 and £100 respectively with patience.

good luck with whatever you buy.

[John]

Well, I shaln't be waiting for access here. I had the impression that Astromart was more US based - is this not the case?

Tim

P.S. Not being able to post in Buy/Sell seems fair enough, not being able to look, on the other hand, appears to penalize the members that do have access and can't sell to newcomers.

Astromart is US based and there is a registration fee plus most sellers there are not keen to sell outside the US.

UK Astro Buy & Sell is UK / European and a good place to browse until you have access to the SGL Buy & Sell section. The rules on access to that are there for a good reason so I hope you can respect that

E.bay is not recommended unless you know exactly what you are looking for.

Do your research before you buy and feel free to ask as many questions as you like here before you commit - the world of eyepieces is more complicated than the world of scopes in many ways