Looking for something in the 15 - 20mm range

[Jimtheslim]

Hi all,

I'm in the market for a medium-low power eyepiece to go in my 10" f4/7 donsonian. I have a nice 10mm BCO and a 32mm plossl from my old scope which is pushing the limits of exit pupil. I quite fancy something in between these for lunar and possibly DSO observation that is going to give me a fairly wide field of view.

Budget wise I suppose, if I have scrimped enough by the end of the month I could potentially be looking at about £100, so I can maybe afford something with a half decent field of view.

I have had a look at many brands and considered many second hand purchases from ebay but just thought I would look for a bit of advice before taking the plunge. Are there any that just aren't worth their price tag? Any to avoid from experience?

Thanks

[rockystar]

maybe the Explorer Scientific 68s at that price? They generally get a good reviews, I've got the 24mm 82, it's a great eyepiece, and if I didn't already have the Morpheus, these are what I would be looking at.

[Ricochet]

http://www.bresser.de/en/Sale/Display-Items/Explore-Scientific-68-Ar-Eyepiece16mm-1-25.html

On second thought, not sure how well these will hold up at f4.7, they're rated for f5 or higher so it might be a bit borderline. 

[Jimtheslim]

I had been very tempted by the Explore Scientific 68 degree, this being bang on budget.

[bingevader]

The ES 82° 18mm is slightly over budget, but also rather splendid

But then you are into 2" EPs.

[Jimtheslim]

I like a good excuse to go over budget, plus I have a 2" adaptor

[Jimtheslim]

However a good, in depth review of the 82's using a 10" f/4.7 suggests the 14mm is the one to go for.

[jetstream]

My 10" f4.8 loves eyepieces in the 21-25mm range with filters Hb,UHC,OIII- I'd not be without an eyepiece in this focal range. The 18mm ES 82 is also a very good eyepiece in these scopes, a great galaxy locator among other things.

[Jimtheslim]

The more I read, the more reviews seem to conflict with each other. A few reviews seem to really put the ES 82's down. Seems you really can't have your cake and eat it with wide field EP's.

[Paul73]

My f4.7 10" Dob loved the 24mm ES 82°

It also loved the Max Vision 20mm 68° which should be bang on budget (the 16mm is good too - but the 20mm was my favourite). Some say that the optics are the same as the ES versions. 

Paul

[Jimtheslim]

The more I read, the more I keep pushing myself into thinking I should go for something in black and green. Question is, are Televues that much better that they would not be susceptible to all the nags and niggles that people seem to have with eyepieces at half their price? I unserstand that a fast 4.7 will likely show up more of the flaws in an eyepiece, however seeing a few come up for sale second hand recently suggests that not everyone gets on with them?

[YKSE]

32 minutes ago, Jimtheslim said:

Question is, are Televues that much better that they would not be susceptible to all the nags and niggles that people seem to have with eyepieces at half their price?

Maybe you can specify what nags and niggles bother you? All reivews are not of equal quality, and differences in our eyes and our observing habit, last but not least, cost,  acount for different prefences.

[Jimtheslim]

Just now, YKSE said:

Maybe you can specify what nags and niggles bother you? All reivews are not of equal quality, and differences in our eyes and our observing habit, last but not least, cost,  acount for different prefences.

Edge of field brightness, shadowing at the edge of the field of view on planets, off axis performance, things like that. With a lot of eyepieces one review will say they are great, then others will say they have flaws and they really don't like them. That is unless people are paying around the £200 mark in which case I can't seem to find any bad reviews or anything people don't seem to like about them.

I suppose the main question is whether I will get a lot out of a medium-low or medium-high powered eyepiece with a generous field of view. I have a 10mm BCO which I absolutely love for planetary. Eye relief is not really a problem and neither is nudging the scope. However having never tried a wide field eyepiece I have nothing to compare it to and would like (and I am willing to invest in) a good eyepiece for DSO's that is going to give me the 'wow factor' when looking at them. 

[YKSE]

As far as I understand it, there is NO optical explanation to Edge of field brightening, some observers see it under some conditions it, in some EPs, some black and greens included.

While the opposite, Edge of field darkening, i.e. vigenetting, (easy optical explanation) exist i many eyepieces, but our eyes are very insensitive to gradual darkning, 50% darker edge can easy escape detection.

There're many off axis aberrations, when someone says sharp to the edge, they only mean undetectable astigmatism, there're comas (comes from the fast mirros), latteral colours, field curvatures (can be from a scope or EP), there're distortions (Pincushion, barrel or AMD).

For DSO, I doubt you can get an EP giving the same WOW effect as you looked at the Moon for the first time through a scope in your backyard. You can only get the WOW effect in a dark site compare to what you see in backyard, using exactly the same setup.

[CraigT82]

If eye relief and scope nudging isn't an issue, and you already have the 10mm BCO, perhaps the 18mm BCO would be a good buy? I've had one for a few weeks and it really is a great DSO eyepiece. Very sharp and with excellent contrast and light throughput. Plus the narrower FoV helps eliminate distractions! (Well that's what I tell myself anyway). It also barlows very well which would give you an extra planetary eyepiece. 

[Jimtheslim]

I haven't had a chance to use the BCO on the moon yet, although lunar isn't my priority I maybe should have said that I do enjoy viewing the whole moon in the eyepiece which I think I might just manage with the 10mm BCO?

As for the 'wow factor' I referred to earlier I was quoting someone who was reviewing the TV Naglers when looking at Saturn and the moon, stating that the amount of colour and contrast was beyond anything they had seen before and the sharpness across the field gave almost a 3D effect. In short there seems to be at least one bad review or one aspect of an eyepiece that people don't like, however this doesn't seem to apply to TV's, especially the Nagler and Delos range.

[Louis D]

The 17mm Nagler T4 is sharp across the field in a Newt when used with a coma corrector.  Without one, I find I have to refocus the edge slightly, so there might be some field curvature.  I like the fact I can use it with eyeglasses to correct my severe astigmatism.  Used, they go for about $250-$275 here in the states.

[bingevader]

6 hours ago, Jimtheslim said:

Seems you really can't have your cake and eat it with wide field EP's.

I had my cake and ate it all, as I have the 18mm and the meade equivalent of the 14mm.

The 24mm ES/Maxvision is still available from FLO too. It's no wee timorous beastie, but it's stonking for the money.

But now we're talking about the makings of a set of 82° EPs, not just one!

[YKSE]

1 hour ago, Jimtheslim said:

I haven't had a chance to use the BCO on the moon yet, although lunar isn't my priority I maybe should have said that I do enjoy viewing the whole moon in the eyepiece which I think I might just manage with the 10mm BCO?

As for the 'wow factor' I referred to earlier I was quoting someone who was reviewing the TV Naglers when looking at Saturn and the moon, stating that the amount of colour and contrast was beyond anything they had seen before and the sharpness across the field gave almost a 3D effect. In short there seems to be at least one bad review or one aspect of an eyepiece that people don't like, however this doesn't seem to apply to TV's, especially the Nagler and Delos range.

Glad that you enjoy 10BCO, there're wouldn't many (black&green included) wide field EPs beat it for planetary view.

Planetary observing are much more seeing dependent, if you have your scope collimated and cooled, you'll get your share when seeing cooperate.

There're many reviews/first lights online, some more enthusiastic than others, I prefer to read those who can make better distinction of what details they see, with good descriptions what aberrations/characterics of eyepieces have, such as this one:

http://www.cloudynights.com/page/articles/cat/user-reviews/24-26-mm-eyepiece-comparison-r2651

it was almost totally foreign to me a few years when I read for the first time, with time, I've learned to know quite some of stuffs written there.

[Timebandit]

Hello Jim. I have come to the conclusion with fast scopes (mine 4.6f) you just need to be so fussy with what eyepieces you put in your scope. A fast scope will show up flaws in a eyepiece that slow scopes will be happy to cope with. For this reason I mainly use televue. If my memory serves me correctly these can be used to 4f scopes.

If you are looking for eyepieces in the 18 to 20 mm range I can suggest some if this is help. Firstly and a cracking eyepiece IMO is the televue nagler 20mm in 2". A great eyepiece for wide angles and dso finding.The only thing is you will need up up your budget some, even for a secondhand one as they are not cheap.                                        Another eyepiece that I have have which works well in my fast scope is the William optics uwan(82 degree). These are nice eyepieces for the money and more in the range of your budget.

I hope this gives you some ideas to possible eyepieces that may be suitable☺

 

I

[Jimtheslim]

thanks for the above, probably the most comprehensive and informative post I've seen on the subject. Whilst a lot of the technical stuff might have been a bit lost on me it's good to see the relative performances at a glance. Seems it might just be time to complete my set of BCO's and wait for a night I can actually use them!

 

[CraigT82]

The Skywatcher nirvanas are identical to the William optics uwa and can be had for ~£100. I'm pretty sure there may be a couple on ABS right now 

[Charic]

10 hours ago, Jimtheslim said:

The more I read, the more I keep pushing myself into thinking I should go for something in black and green. Question is, are Televues that much better that they would not be susceptible to all the nags and niggles that people seem to have with eyepieces at half their price? I unserstand that a fast 4.7 will likely show up more of the flaws in an eyepiece, however seeing a few come up for sale second hand recently suggests that not everyone gets on with them?

In a fast scope the difference/niggles may be perceptible,  if your looking for them, however you won't know unless you try?
TeleVue no doubt will have an eyepiece that would suit your needs, depending on your expectations?
In my slower f/6 scope,  I found on my last test that my 8mm EP's BST/Delos produce the same image and brightness, with  the field of view 72° over 60° making any difference, which is not really necessary for all targets. I had hoped to purchase a faster scope,  larger aperture, hence my thought process of possibly needing the Delos which are tested at f/4.
Considering their drawn from the merits of the Ethos, set aside the BST Starguider, it suggests to me the Starguider is a good eyepiece for what they cost, and for my needs alone, and I'm more than happy with their 60° afov.
Its not just about branding and the costs, its about what suits you best, your eyes, your scope, a perfect setup, and  perfect conditions, so your right to question your needs and requirements.

[jetstream]

The 18mmBCO can run with the best of them... the other night an excellent sky made the 17mm Ethos pull right away however (OIII on the Veil). My point is that sky darkness will allow the better eyepieces to excel and strut their stuff. Same goes for seeing and planetary/lunar obs. Under lesser skies many eyepieces will show similar views regardless of brand/model etc.

I like the 18mm ES 82 better than my 16T5 Nagler on everything and the 18mmBCO fits a "niche" in that it is superb for keeping bright stars out of the FOV when trying very faint objects with filters.

You will be hard pressed to find a better EP than the 10mm BCO ... but you might want a 2" widefield 20mm-25mm for filter use? or great views of the Andromeda galaxy etc?

[Roy Challen]

18 hours ago, YKSE said:

 

For DSO, I doubt you can get an EP giving the same WOW effect as you looked at the Moon for the first time through a scope in your backyard. You can only get the WOW effect in a dark site compare to what you see in backyard, using exactly the same setup.

Very true, an eyepiece cannot improve your observing conditions, but the observing conditions can improve (also degrade) the view through the eyepiece.