10mm Ethos and my 9mm BGO

[alan potts]

Ethos 10mm and the 9mm BGO

Let us start first with why do such a head to head with two so dissimilar eyepieces. I have to admit they do not come a great deal less like each other than these two; with a 60 degree field of view, price and size difference.

A few days back, ‘Pig’ one of the site members posted a review using the BGO and a 10mm Delos, an eyepiece I had myself until I carelessly smashed it, a heart stopping moment I do assure, as it was in my APO as it fell from the mount.

I must state this report is of course not intended to prove him wrong or intended to offend him in any way, he reported what he saw.

His BGO seemed to perform somewhat poorly matched against the 10mm Delos, which is a fabulous eyepiece and maybe even a little better than my 10mm Ethos, though apart from the field of view I would only expect there to be subtle differences between the two. In a somewhat super fast review by my own standards I wanted to see if I could see any differences in my two eyepieces, it goes without saying I will try not pay any attention to the FOV differences, though that may well be very hard.

I got the 9mm BGO when I was in England in May and sort of got stung a bit by the feeding frenzy that was underway at the time, but 85quid is not a fortune and I have been more than happy with this regular visitor to the focuser. At the same time I was selling the 10mm Delos something I wish I had not done,  though it’s new owner is very happy with it, I am sure I will be tempted to buy another one some day. I never owned the Delos and BGO at the same time so I cannot replicate the test in full, neither can I the conditions.

The 10mm Ethos is as many times as larger as it is expensive when compared to the rather tiny BGO, a hand full type eyepiece if ever there was one. This in truth will be the first time I have really got down to some serious work at the scope with this Ethos, before it has only had the odd 10 minutes here and there.

Normally I would repeat all my observations on at least two different nights so I had a range of conditions to add to my pages of notes but on this occasion it is a one night stand, so to speak. A Pottsy report that has bulimia.

APM, 115mm, Ethos 10mm giving X80.5 and the BGO X89.4

I selected some targets that I have been using of late just to make it easier for me.

M11 The Wild Duck.

Whilst this magnification is not massive it sure puts some stress on the Goto system when you have a BGO with its 40 degree field of view in the focuser as it didn’t manage to find the target. Fortunately it was not very far away and this is a subject that can be seen in the finder. I swapped back and forth a good few times and you could be forgiven for think it was a different Messier object when changing over to the Ethos. I had to really look deep with concentration to study the two absolutely totally dissimilar views. It was almost as if the magnification changed by at least X30-40 instead of less than X10.

Over all I felt the BGO, though a little more difficult to use, framed the subject better than the Ethos thought I liked the view given by the Ethos more. Optically I would have said the centre star mass of the cluster was a little easier to see with the BGO, the transmission could have been a tiny bit better or the extra X9 in the power range was making the difference, which I doubt myself. Only paying attention the centre of a field of view when there is so much to look at is not as simple as I thought, it realty is astounding how sharp the Ethos is right to the very edge, and I do mean the very edge, these truly are amasing eyepieces.

I could not detect any distortion in the centre of the Ethos and I am sure there wasn’t any, I give the plaudits to the BGO because though subtle I felt it was slightly optically better, but not sharper.

Messier 22.

Though this globular is low down now and we are looking through rather more atmosphere than we would like it is still a good test on this scope to see if any stars can be resolved from the centre mass. With this being a good size stars can be teased out at magnification well under X100, though there is no substitute for aperture on these.

Both eyepieces showed a good few stars clearly seen separate from the others and I have to say again the BGO was marginally the better performer but believe me it is very difficult to assess the differences between these because of the field of view, the BGO automatically concentrates the eye onto the subject where with the Ethos you have to hunt for stars, I would have really liked to have double checked my findings on this.

GSO 150 RC. Collimation checked. F/L 1370mm

Jupiter.

Yes, I was up and out at 0400hrs to see this yesterday, I was praying it didn’t turn foggy as it does sometimes at this time of the year. I went out to be greeted by 4 toads that were hopping around the scope, which I had left out from the night before, one of the nice things about living in the middle of nowhere is you can do this.

The Ethos give a very usable X137 and with the massive field of view the Goto managed to find the planet which was well over head and in the better part of the sky which was not the best I have seen all year, the horizons were somewhat hazy and far from what I have had. However the overhead was dark and clear.

This is my first sight of Juptier this year and I had forgotten just what a site it was, belts clearly on display and the polar regions as well, I almost feel there was some detail in the thick equatorial belt that was trying to give itself up to me. I changed to the BGO and an extra X15 of power and I could see a difference which for me then is not a fair test, but I pressed on. The belts seemed to be more prominent with the 9mm and the disc a little whiter, how much of this was the extra power and how much was the smaller field concentrating my eye on the planet, I don’t really know. Both eyepieces gave a very pleasing view of the planet and the BGO was without doubt the better eyepiece for this job, after all most people use these type of eyepieces mainly for planetary viewing. That is not to say that you cannot use the Ethos for this as it is easy on the eye and has a good deal more eye-relief over the 9mm BGO and I believe you can use them much longer without getting eye strain but it would not be my first choice for Jupiter.

M42, the Orion Nebular, (as if you needed telling).

Another first of the year and I was surprised at where Orion was, a few more hours and it would have set. The BGO gave a wonderful but restricted view of this stellar birth place, both E and F components were visible in the clouds and the view was generally superb. The Ethos however gave what I think was a better view, you just cannot ignore the mass of stars around this area. Sticking strictly to the subject matter, I don’t believe one eyepiece was any better than the other, though the ‘E and F’ stars of the trapezium were a little easier to see with the 10mm. This is very much a magnification matter, once you go outside of a certain band they can be a problem to see and it is not always the same in each scope.

Venus.

A few nights before the conditions were not too good, cloud being the main offender, but Venus was there low down between two walnut trees. I like to use this planet for testing the light scatter of eyepieces as not many things are brighter. I have to say the BGO afforded me the best view I have had this year of the planet, very little if any light scatter that I could detect and no aberrations. There was a little from the Ethos but not so much that you would consign the eyepiece to the dustbin afterwards and again the sharpness was on a par with the BGO. Just as I was getting comfy and enjoying the sight one of the trees got in the way and then the clouds moved in.

Ring Nebular.

I have always wanted to see this object through a massive scope and I guess so have a few others. Tonight I have to content myself with a 150mm which has reasonable optics for the outlay. Though it was made mainly as a photographic scope I find at F 9 it has enough contrast to use visually. The Ring is a target that at low power can easily be over-looked, now using the Ethos as a finder eyepiece the goto system placed it almost in the middle, not surprising as I used Vega as one of the alignment stars. I just had the feeling the BGO was making the void in the centre stand out just a tiny bit better, I spent about 30 minutes swapping back and forth but there was so little in it. There was no sight of the star in the middle which was no shock to me, a scope twice the size and I could have been in with a shout, but even then it would be no sure thing.

Conclusion.

I believe that unseen and changing conditions could have accounted for Shauns BGO giving a poor show or there is a possibility that his eyes just don’t get on with them, they are not everybody’s cup of tea. It was only this morning that I read that one site member was selling a Delos because he could not get on with it.

I must here give credit where it is due Shaun reported as he saw it, just like I have, who is to say I am correct, we can only report what we see. Well done.

It could equally have been a faulty eyepiece, no process is perfect, I hope it is not this as I believe it was bought secondhand.

I do not believe that the performance difference between the Ethos and the Delos is not significant enough to worry about, though there will be differences in the very subtle ways which each portrays contrast, scatter, aberrations and even sharpness. Though I prefer to use the Ethos for every-night viewing there is no doubt that when it comes to sharpness and contrast on a planetary subject the BGO is really are hard to match and at even 85 pounds it was a clear bargain.

As interesting as it was doing this I think we should stick to horses for courses as I don’t believe the 10mm Ethos was ever designed as a planetary eyepiece. It is also remarkable that an eyepiece with such a large feild of view can hold it's own with one of the sharpest acts around.

Clear skies.

Alan          

   

                                                                                           

[Damo636]

Another fantastic report Alan, thanks for sharing! I've never owned the 9mm but have had the 5,6 & 7mm, and eye relief aside, thought them excellent. I'm actually toying with the idea of springing for a couple of the new Fujiyama offerings, purely for planetary/double star viewing.

[YKSE]

Allan, another solid observation report, an enjoyable reading and many things to learn for me  .

[Pig]

Excellent comprehensive review Alan   I always enjoy reading them and thank you for considering my findings

[Joves]

Nice report, Alan.

[Dude_with_the_tube]

Fantastic report Alan,pleasure to read and I am very pleased with your result showing tha BGO are and will be excellent eye piece.

clear skies.

[Rustysplit]

Another fine report Alan.

I think that sometimes in the rush for wide fov's we lose sight of the reality of looking at targets. Many of them demand close scrutiny, and possibly all that extra starfield does is distract us. That said, on those expansive targets, and if you get on with them....

[alan potts]

Alan,

This is a very good point and if we all had a pot full of money to spend it would be great. I myself believe at some focal lengths we do need more than one eyepiece, this will vary of course depending on your scope. I have duplications at 6mm 7mm and 9mm with the BGO's but would really like some Delos in there as well. I would also like some other eyepieces to write about but that would mean me having to go out and buy them and that's not really an option. I may see what I can pick up secondhand next time over in England without spending a packet.

As for the 2 eyepieces in question here I found it a bit like making a comparison  along the lines of garden pond, Atlantic ocean. I did start out some time back with an Ethos in a review with a BGO and then dropped it because it was difficult to do. I think to be honest if you are making a comparison you can do Ethos Delos or Nagler but to drop below a FOV of 60 degrees really makes it hard work. 

AP

[Joves]

You did it very well though, Alan. You were actually very respectful of each eyepiece, taking into account what they were each clearly designed to do, but giving a very good depiction of the strengths of both. I like that there didn't have to be a "loser" in this type of review!

[Charon]

Excellent report Alan.

[alan potts]

Joves,

I agree why should there ever be a loser, in this report they were both top quality eyepieces. For someone in this hobby that don't have a mass of cash to spend on top line eyepieces they may well think there own eyepieces are winners, and why not. I have to say though that anyone that is on a tight budget will do a lot worse than buying a S/H BGO of any focal length, if they have a down side it is the eye-relief though never really a problem on the 9mm.

Alan

[AlexB67]

Nice report Alan, I would strongly consider a BGO myself at that cost and the generally great reports they get, but it would fall into the camp of having to try one to see if my eyes can get on with them.  Seems to me at the cost they are they're hard to beat for the return in quality at the FOV they offer.

[alan potts]

Alex,

Stating the obviuos here but a star party is a good place to try one.  I find them very good on globulars as well as planets, they focus your attention to the subject in a way the wider eyepieces can't. If you are using a wide field eyepiece you have to concentrate on the subject more, I find, the BGO and other orthos sort of do it for you, and they have a flat field.

Alan.

[AlexB67]

Alex,

Stating the obviuos here but a star party is a good place to try one.  I find them very good on globulars as well as planets, they focus your attention to the subject in a way the wider eyepieces can't. If you are using a wide field eyepiece you have to concentrate on the subject more, I find, the BGO and other orthos sort of do it for you, and they have a flat field.

Alan.

I can well imagine Alan, I was exactly thinking about it for that reason. I like it when something fits within  a well defined frame and has a clear field stop. Of course I've never owned a properly wide angle eyepiece, but a Delos at 72 would be plenty for me I think in my scope in most cases, being a fairly fast one. In an ideal world though a very wide  FOV and where keeping the exit pupil down would be nice in some cases,  but in general, quite often I feel I could live without it. In my scope with the FOV that large a CC would be a must anyway I imagine, I can live with coma, but I suspect there will come a point where I say this is too much for my liking. 

I suspect 100 degrees or something my eyes may well start swimming around the view also. In any case, a very wide FOV is also something that definitely would come into the try before you buy camp for me.

[alan potts]

Alex,

The good thing about the orthoscopics is, unless you are talking the likes of Zeiss, they are affordable. I mean S/H now you can pick them up fo 50-60 pounds or even less for some of the other brands. The massive field of view or Atlantic Oceans as I called them earlier are somewhat more costly. I sat on the fence for a good while and it was reading Johns reviews that got me interested in them. I had to buy blind, not knowing what I was going to get and now I really enjoy them, I am even thinking of a 5mm BGO or Hutech now. I used to have a Meade 5.5mm Plossl from the 5000 range and I could use that though it was a bit of an effort with my eye lashes.

Alan

[alan potts]

I tried these two last night in the 180mm Mak on the Moon, stunning on both counts with the 9mm BGO you almost get a whole crater in the FOV. It really is amasing how much magnification the Moon will take, X270 and X300 are very high for me, the seeing was hold ing well too.

Alan.

[John]

If you have a fast scope, the ability / preference to live without an ultra-wide field of view is admirable and also economical 

In my case I find now I enjoy both the Ethos and Ortho viewpoint on the universe, which is odd really as they are so different, but there you go   I'd miss the ultra wide perspective more though, If I had to do without it.

I appreciate that not everybody likes / needs / wants a really expansive view though, or a narrow one for that matter, so it's great that there is so much choice in eyepieces available to us right now. 

[bingevader]

I went out to be greeted by 4 toads that were hopping around the scope, which I had left out from the night before

You must be more careful to put the toads away next time. 

Super report as always.

You do you're self a disservice by suggesting it is light weight or slimmed down, it's very comprehensive!

Cheers

[alan potts]

Bingevader,   This one was a little slimmed down and I did not spend as much time on it. I always like to check findings on different nights, at least two, to make sure I not talking tommy rot.

John, Thanks to you I also like both ends of the FOV spectrum though I am not sure I could get on with the Super mono's that I know you once had, I feel 30 degrees could better a little too small. I don't suppose I will ever get to try won so maybe I will never know. I am not sure as I said in the report that one should ever reallt test these two extremes against each other, but it was something different. Thanks to the recent case of magnification fever I am now thinking of the 2.5mm XO that TS still have.

Alan.

,

[John]

I had a 2.5mm Nagler T6 for a very short while. Great eyepiece but awful floaters which are my eye's fault not Tele Vue's 

3mm is the shortest I'll use now. 

The TMB Supermono 5mm is the best planetary type eyepiece I've ever used but also one of the most challenging because of it's tiny eye lens and 30 degree AFoV. It's eye relief was no worse than a normal ortho. I'd like to try the Pentax XO 5mm sometime though.

The prize for the most challenging eyepiece I've every used has just been taken by the Fujiyama HD 4mm Ortho. Optically just as good as all the other Fujiyama, Astro Hutech and Baader Genuine orthos but the minute 3mm diameter eyelens set in a more or less flat and featureless satin finished eyepiece top is very, very difficult to find with the eye in the dark.

[Joves]

Have you fellas ever had the chance to use a Vixen LV 2.5mm? I've had one for a long while, but until getting the TV-76, really haven't had a scope to use it in (even the TV-76 is kind of getting toward its limit with this FL eyepiece). Haven't had the conditions to test it out on this scope yet, but would be keen to hear your thoughts, if you've ever tried one.

[alan potts]

Something makes me think you have posted this in the wrong place Joves. However I am thinking of a 2.5mm but most likely the Pentax XO, if not the Nagler.

Alan.

[alan potts]

Sorry, didn't read the reply from John beforehand.  The 2.5mm XO is a different design I believe to other orthoscopics allowing longer eye-relief, how much longer I don't know but it will not be a 20mm ER of the Radian longer.

On the 4mm reading between the lines it sounds like a difficult one to use and maybe some will not be able to use it., ER must only be 3mm or so.

Alan.

[John]

Sorry, didn't read the reply from John beforehand.  The 2.5mm XO is a different design I believe to other orthoscopics allowing longer eye-relief, how much longer I don't know but it will not be a 20mm ER of the Radian longer.

The Pentax XO 2.5mm has 3.9mm of eye relief and the 5mm has, somewhat oddly, 3.6mm. Due to their recessed eye lenses the actual physical eye relief available is around 1mm less than these figures. Tight, tight, tight ...... 

[alan potts]

With my lovely long lashes that the girls at school always wanted to get there hands on it sounds like that is going to be rather short for me.

I did manage to use the 5.5mm Meade S 5000 plossl but even that was not easy. This is no doubt where the Radians and the Delos win through. Lets face it even the Nagler zoom which is the tiniest bit behind the orthos in a few areas with it's 10mm of ER takes the spoils for many people.

Alan