John

My Tasco 60mm refractor is probably 50-60 years old but I don't think of it as a classic. The TAL 100 RT (bottom photo) was around 20 years old and yet I do think of that as a classic. Odd, isn't it

Thanks for the continued and quality input folks. I've been following the discussion with interest but some of the optical theory stuff has me teetering on the brink of @Stu's cliff so I've not added thoughts of my own to avoid the possibility of falling off !. I recall that for quite a while, the author / reviewer Neil English was a great proponent of long, slow refractors although he was never a fan of the expensive, shorter apochromats or "poodles" as he termed them. Lately however Neil has had a change of heart and favours newtonians. http://neilenglish.net/optimising-an-8-inch-newtonian-for-visual-use/

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.

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.

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

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.

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:

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

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 !

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.

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 ?

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.

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

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 !