John

The ES 92 eyepieces have proved very popular for those who wear glasses when observing because they are practically the only hyper-wide eyepieces that give eye relief that is sufficient to allow them to access the full AFoV although, as Don Pensack says, there will be some movement of the eyeball, and maybe, albeit unconsciously, the head, required to do this.

For me as a non-glasses wearer, I found the eye relief of the 12mm too long and therefore the eye positioning awkward and the 17mm almost so but I did manage to deal with that one better. They are both very large and heavy eyepieces with very high optical performance even in scopes down to around F/5.

32 minutes ago, Sunshine said:

... I mean we all read opinions then spread those to newcomers over years and years. There are some things which I always thought were absolute irrefutable facts until, someone explained why said "fact" it is not true. 

I think that is an issue. Certain things do get repeated over and over without necessarily being re-tested. Every now and then some experienced and helpful person does post a "myth busting" piece which is great but many of these "facts" do seem to be like zombies - hard to kill off !

Also, some information that had some validity 20-30 years ago has been rendered obsolete / inaccurate by optical and technological developments over the intervening years. I'm sure those of us who have been around for a few years can all think of examples of that !

If these expensive brands have managed to somehow fool many experienced astronomers about their optical performance for a couple of decades, that's quite an achievement !.

I have one of the clones but it looks identical to the Hyperflex 7.2 - 21.5 zoom (and a few other brands versions as well). It has quite a narrow field of view at 21.5mm but overall I think it is a good performer for what it costs. Mostly I use it with my refractors (F/6.5 to F/9.2) but when it has been in my F/5.3 12 inch dobsonian it has not disgraced itself. It also works well with the Baader Q-Turret 2.25x barlow IMHO to give a high power 9.55mm - 3.2mm zoom.

1 minute ago, neil phillips said:

There was a testing facility in Europe ( russian if i remember ) where they tested almost all known brands commercially available. The results were very interesting. Not sure if anyone has that link. But its quite informative 

There was a German forum called astro-foren or similar that published tests by a Herr Rohr. There are some in this blog:

http://interferometrie.blogspot.com/

This describes his method but it is in German:

http://r2.astro-foren.com/index.php/de/

I'm out of my depth when it comes to detailed discussion of optical testing and results to be honest. Respect to those who know what they are talking about in this area

4 minutes ago, vlaiv said:

That is really interesting - they quote peak-to-valley error of no more than 0.24 (for scopes up to 150mm of aperture) - that is just a tiny fraction better than 0.25 or 1/4th of wave P2V.

What they are really saying - our scopes are "diffraction limited" or have Strehl of higher than 0.8.

Maybe we are being mislead by low cost scopes that advertise as "diffraction limited" - maybe they are much poorer than that?

I believe that all LZOS objectives are guaranteed to have a strehl of 0.95 or better ?

APM put the specs they use for their LZOS objectives in the public domain. I guess they were stringent back in 2005 but maybe not so much today ?

APMApo-Linsen-Spezifikationen.pdf

My priority has always been to try and get the best optical quality that I can afford. I've never been too fussy about focusers etc or even the quality of fit and finish, as long as the optical quality is there. With the more expensive scopes I would hope to get better quality in these departments as well.

Although not too fussy about focusers, even I can appreciate that the Feathertouch fitted to my TMB/LZOS 130 is something above and beyond anything else I've used though.

With a triplet refractor I think the mechanical design and precision of the objective cell is very important as well. Another area where the LZOS triplets seem extremely well executed. I'm sure that Tak and Astro Physics have great quality objective cells as well.

6 minutes ago, neil phillips said:

Did you take that plant photo John ? 

No, it was a chap called Chris Morris. Wishbone Ash were playing the Bristol Colston Hall on that night and apparently came over to watch Robert as well.

This thread will be modded soon, I'm sure

Thanks to @vlaiv for getting it back on track - I'll have a think about his questions 

Nearest I got to seeing Led Zeppelin was seeing Robert Plant and the Honeydrippers at the Bristol Granary in May 1981. Their gear took up about half the dance floor. Grainy pic of the atmospheric but cramped gig:

I guess we better get back to expensive telescopes - I certainly could not have afforded one back then !

Aries is a manufacturer that is not much heard about. They are probably best known for the Chromacor CA / SA corrector but also produced some fine scopes such as this fluorite doublet 178mm. Unusual to get a doublet of this spec:

1 hour ago, vagk said:

What I have read about 12mm 92° is that you observe whole 92° AFOV at a glance instead of ethos or es 100° which you must move your head and eye to capture whole field of view. This must be spectacular.

Isn't worth the sacrifice of ergonomics and weight for 32 degrees extra AFOV with the same eye relief ?

Personally I don't need to move my head to see the full field of the Ethos but I know that some folks do. Seeing the whole of a 92 degree eyepiece with nearly 20mm of eye relief is going to be a little easier than for a 100 degree eyepiece with 15mm of eye relief, especially if you wear glasses.

Optically the ES 92 degree eyepieces are excellent - the best that I've used from ES by some way. I just did not find the eye placement suitable for me.

Not sure how to answer the final question - I enjoy both hyper-wide eyepieces and ones with around 70 degrees as well. I usually use the 70 degree ones in my refractors and the 100 degree ones in my 12 inch dobsonian.

When I've had Skywatcher scopes with that focuser I've found that they can be improved and adjusted to perform quite well, at least for observing purposes.

The rack and pinion focuser on the Evostar 120 is a close copy of the Vixen focuser. A method for adjusting the Vixen focuser is given here and this does work for the Skywatcher versions as well:

vixenfocuser.pdf

"Stairway to Heaven" would be a decent name for a scope

2 minutes ago, Captain Magenta said:

One thing that has struck me is how many SGL “equipment“ photos, often in the “postie” thread, have a guitar in the background. Also I’ve made two eBay purchases of astro equipment, and on collection, guitars were present too.

Magnus

I'm just listening to "Whiskey in the Jar" by Thin Lizzy on the radio as I type this. Eric Bell's riffs send shivers up my spine even though I could not play them !

15 minutes ago, Stu said:

 

I think these two quotes can be related, and support the fact that there is a benefit to buying the best kit you can afford. I disagree with the confirmation bias comments in many cases and think this is somewhat disrespectful to people who own top end kit, particularly if the people making the statements haven’t had the opportunity to compare.

My FC100DC is my favourite scope for a variety of reasons. I could summarise it simply as ‘amazing views in a very compact, lightweight and versatile scope’. It does most things very well and a few things brilliantly, plus it can always be with me because it’s so compact. A 100ED f9 may get close, but it’s not airline portable for instance. I’m not blind to the Tak’s limitations and am on record a number of times on the forum saying that my Heritage 150p has humbled it on targets such as Zeta Herculis. This may be hard to swallow but is a fact.

As an example, I used to have an Astrotech 106mm f6.5 fpl53 triplet apo which I bought as a demonstrator for not far off Tak money. In fact the very same scope was reviewed by our own @steppenwolf 12 years back here:

I always thought this was an excellent scope, fantastic on widefield with an OIII and 31mm Nagler giving a 3.6 degree field of view. I also used it for Lunar and planetary, plus solar with a Lunt Herschel Wedge. I was always happy with the views at the time. I can’t recall exactly why I sold it, but it’s eventual replacement was a Tak FC100DC.

The Tak has a slightly longer focal length (740mm vs 650mm) so was not as good at those widefield views (I now use a Genesis for that). However, I saw a distinct improvement with lunar and planetary observing in terms of contrast and detail seen. Particularly details on Jupiter and views of the shadow and moon transits we’re clearer in the Tak.

Another improvement was in solar observing. Even with the Lunt Wedge I saw detail which was sharper and finer than in the Astrotech, but when I added the Baader Coolwedge there was a further incremental improvement at higher powers, then the Baader Zeiss Mark IV binoviewer and Zeiss Orthos all helped. Getting everything optimised in the optical train really does help maximise the visible detail and by that I mean granulation cells and penumbral ‘petal’ structures at high powers eg x200 and more. I see people say white light solar is boring, but it rarely is in the Tak. Often people say that a fast achro for solar is fine because you can use a continuum filter to remove CA. That’s all well and good, but SA kills the fine detail that you can achieve with a decent apo (or even a very well corrected long focal ratio achro).

I’ve always advocated the use of good value entry level kit where I think it performs well eg Heritage 150p, and I push back against constant recommendations that it should be Televue, Pentax eyepieces or nothing. Some one entering the hobby can have many years of enjoyable observing with a relatively cheap scope and a set of BSTs. BUT, high end kit does have its benefits which are still realiseable (is that a word? 🤪) in the U.K. when conditions are right.

A final example was when observing the Trapezium with Gavstar, my apologies I can’t recall if it was with the TEC160 or AP 130GTX though I suspect the former. Anyway, viewing E & F in the trap has always been a challenge for me, particularly with F as it’s there one minute, gone the next. In this scope they were just ‘there’ rock solid and clear all the time, best I’ve ever seen. Now, I know the conditions were good, but the scope certainly made the most of them.

Will I ever shut up? 🤣🤣

Last thought. Use and enjoy what you’ve got and can comfortably afford, but don’t disregard high end kit and if you get a chance to have a look through some, grab it 👍.

The end 🤪🤪
 

Very interesting Stu - thanks for posting

When I've put the Herschel Wedge on my Tak FC100 the white light views have been better (sharper and more contrasty) than I've seen through my other refractors I have to say.

6 minutes ago, ollypenrice said:

Sorry for the diversion, John, though I think your post is more about people and their motivation than it is about telescopes.

Olly

No problem at all Olly. I think you may be correct in that

I've owned both but I never actually compared them. Probably similar in terms of sharpness and edge correction. Massively different in all physical and ergonomic respects though.

I found the eye relief of the ES 12 / 92 just too long for my comfort. Even with the eye cup fully extended I had to "hover" my eye well above the eyepiece top to get the right position (I don't wear glasses when observing) and, speaking personally, I don't find this a relaxing way to observe. A also have the Ethos 13mm which I preferred over the ES 12 / 92 in practically all respects.

I let the ES 12 / 92 go to a new home quite quickly but held onto the ES 17 / 92 for longer because the eye positioning was easier to hold with that one. I still have the Pentax XW 10mm though.

I would have thought that the Baader Morpheus 9mm or 12.5mm would be a closer comparison to the Pentax XW 10mm ?

1 hour ago, F15Rules said:

Very interesting Tim..I agree with you on the above, but I myself don't fit that bill..I failed Maths O level twice (never did pass!), but I am good with arithmetic...I can't read music but have a good ear for tuning and can keep a beat..I reckon I might even be a bit dyslexic, as I find written instructions hard to follow if I buy a new TV for instance, but find watching a video tutorial or being shown how to do something much more comfortable.

I think another connection between the two disciplines is an emotional response: I've always liked music that touches me inside..in my case it's mainly rock music and guitar in particular..artists such as Paul Kossoff, Rory Gallagher, Robin Trower, Myles Kennedy and Mark Tremonti pull out sounds that make the hairs on the back of my neck stand up. So do vocalists like Paul Rodgers, Eddie Vedder, Myles Kennedy, Amy Lee and Ian Gillan, to name but a few.

In Astronomy, my observing reactions are much more emotional than "scientific": I am blown away by the variety, the beauty and sheer scale of what I'm looking at, and it makes me marvel at how wonderful is the Universe that we are a small part of.

(Sorry to veer a bit off topic John!😱🙂).

Dave

No problem Dave - it was a good "veer"

Rory Gallagher is probably my favourite all time guitarist. I'm so pleased that I managed to see him a couple of times playing live in Bristol

Closer to the topic, my observing is more emotional than scientific as well. I enjoy finding out a bit more about what I've been looking at but that is usually after the "wonder" bit

When I have been comparing high quality optics, it is when the conditions have been particularly good that any differences have shown themselves. But, as has been said earlier in this thread, it is nice to have really good optics for those times when things do all fall into place.

20 minutes ago, RobertI said:

.... I’ve yet to reach the stage of owning my dream Tak, but I can feel it coming!! 🙂

It would be very interesting to compare, in detail, a refractor such as your Altair Starwave 102ED-R and something like a Tak FC100-DF.

The 102ED-R, rather like the FLO's Starfield ED102, seem to be really nicely made, very well featured, and excellent performers from what I've read of them. Just what does the FC100-DF provide for the additional £1,500, apart from the famous marque ?

Maybe there is a comparison report somewhere ?

Better late and a good performer than on time with some flaws I guess. These forums can be pretty ruthless at finding flaws even months before something launches 

Bump: Looks like availability from 19th December:

https://www.apm-telescopes.net/en/new-apm-super-zoom-eyepiece-77-mm-to-154-mm-with-125-connector

32 minutes ago, Piero said:

 

I am aware of that plot in Alvin Huey's website. It's here: https://www.fainthttps://www.backyardastro.org/topic/692-gso-stellalyra-superview/fuzzies.com/AboutUs2.html . I do have some doubts about the validity of it though. In fact, 1) there is no information about the data (and how these were collected!), 2) what is the Y axis ?. As it is that plot seems artificial, if not even speculative. Even after by-passing the row data issue, I am not convinced that differences between eyepieces are "magnified" with aperture as the plot suggests. According to that idea, I should not have noticed any difference between eyepieces with my TV-60, whereas I should start noticing them with my 16". Instead, I saw plenty of eyepiece differences with my TV-60, and the way I can explain this, is because these differences are between 30-150x, far below an average seeing. Therefore, as the telescope was easily operating at its limit, any difference was due to the eyepiece.

In contrast, with fast telescopes of 22" or 30" apertures, a 6mm eyepiece is not even close to the theoretical telescope resolution (~1mm exit pupil), but the delivered magnification is high enough to require almost superb seeing conditions, something which is only rarely met.

Also, those folks observe with ~f4 telescopes without coma corrector. I tried to observe with my 16" f4 without coma corrector for curiosity and the views were degraded nearly on-axis. Now, I don't want to comment on whether a PC2 is required or not in a fast dobson, but my doubts remain: how can one spot substantial differences between eyepieces and spot extremely faint targets in the presence of severe coma like that when details tend to be washed out? And from a theoretical perspective, let's consider the term called `coma free region` which identifies the region where the introduced coma is smaller than the Airy disc. This region is tiny at f4 (e.g. 0.022mm x f/ratio^3 ) and is generally defined on the Rayleigh criterion. If one is assessing top quality eyepieces on threshold targets, it means that s/he is judging way above a Strehl of 0.8. Taken this in consideration, the `coma free region` (which is actually just a dot really..) is even smaller.. So.. to me there is something which does not work quite right there.. 

 

Regarding transmission with modern eyepieces, the only eyepiece which I repeatedly thought it had more transmission than the others is the Vixen HR. Having compared the 2.4mm against a Vixen SLV 5mm with my TV-60, it was quite obvious to see that the image in the HR was almost as bright as the image in the SVL despite half focal length of the former eyepiece. This was also quite striking considering the short exit pupil of the 2.4mm ep using a 60mm refractor (150x). Apart from that standalone case, the other eyepieces I compared showed a noticeable difference in contrast, not transmission to my eye (for instance, both the Docter and the Zeiss zoom show more contrast than the Vixen SLV, Delos, Naglers, Morpheus I've tried).

I didn't take much notice of the plot to be honest. I read their comments in their blogs and thought them positive about the 10mm BCO plus I enjoyed using the eyepiece myself when I've had one.

We each have to find what suits us best though. I don't tend to analyse much - if I like the views consistently and on a range of targets through a few different scopes, I'm happy with the eyepiece

Too easily satisfied I guess

It sounds like you are a much more critical observer than I am

It does look like your 70mm F/12.8 achromat has an excellent objective

I bought a low cost 90mm F/11.1 achromat last year for next to nothing hoping that I could have some cheap, portable fun. Unfortunately I got a rather mediocre performer that time and nothing I've been able to do with regards to collimation or other adjustments has improved the situation, unfortunately

I'm sure there are good 90mm ones out there because I've read about them but I didn't get one, this time around.

Your lunar images look extremely sharp - nicely done !

Fascinating read Dave / @F15Rules - thanks for posting it

Many of the experiences and feelings that you experienced seem to mirror my own.

Having a very keen desire to own a good scope but barely any budget available and then eventually being able to afford a Vixen SP102M especially so !

It is also a good point that there are a number of other interests around where the costs can far exceed what we pay for quality gear for astronomy. And that our investments often do have long useful lifespans

I did get into rock music (still am, really) but could never seem to learn to play an instrument (lack of patience I think ) so I've spared myself some expense there although I did seem to fork out a fair amount during the late 70's through to the mid 80's on tickets and beer going to see gigs.

My son got married in 2019 so that was a pricey year. My daughter will follow suit quite soon I think so we will have to prise open the bank vault again I'm sure

My other hobbies are bird watching and a bit of fishing which are pretty low cost activities thank goodness !

26 minutes ago, Piero said:

That's interesting, John.

My copy was fine on-axis and showed a bit of chromatic aberration near the edge. The eyepiece was completely functional to my eye. Having said this, the delivered view was okay / good, but not something that I would have called "impressive". In other words, it was not an eyepiece I would have kept.. and in fact, I let it go! 🙄

I think it was the folks in the USA using their very large scopes under dark skies that found the Baader Classic 10mm such a good performer on small DSO's. They placed theirs somewhere between the Zeiss ZAO 10mm and the Delos 10mm in terms of ability at that task.

I guess some quality variability in complex products is inevitable even with the best brands.

Academic really - it looks like the OP has gone for another option and I hope that works out well 

1 hour ago, Piero said:

....Regarding the 10mm BCO, my copy bought new was functional but nothing special. Possibly, its low cost is due to poor QA?

I have seen evidence of QA errors in a new Baader Genuine Ortho that was sent to me for testing. The issue there I think was that the lens groups were touching in the centre due, I suppose, to an incorrect spacer or similar. It took me quite a while to work out why the view was sharp everywhere in the FoV apart from a small area right in the centre of the field where it went decidedly mushy as a target passed through it.

So it does happen.