JTEC

Paz, I’ve owned my Baader bino for 15 years and use it a lot. The collimation was set when it was manufactured and has never varied. I can’t think of any circumstance when I’d want to tinker with it - having the facility to do so would seem, certainly in my ham-fisted case, more like an option for disaster than a convenience. As with binoculars, if a unit is properly built and hasn’t suffered damage, to the best of my knowledge, there should be no need to play with collimation. That said, as Louis points out, there are ways in which things can appear out of kilter that have nothing to do with mutual collimation of the two OTAs. I think he’s right in suggesting issues to do with orthogonality around the eyepiece holders and seating, related issues to do with rotational precision of diopter adjustments at the eyepiece end, etc, as the place to look. I’ve also found that things can look a bit wonky with particular pairs of eyepieces. In one case, it turned out that the eps were not in fact as well matched optically as they should have been and this was confusing to the eye. I don’t find all eps equally easy to merge - in particular, I find that merging can be difficult or uncomfortable with some wide field eps and some that seem to display a large amount of sphericity. And, of course, interpupillary distance, though a simple thing, can be quite critical and, if not right, make you think something fundamental is skewiff. Apologies if this is too much like sucking eggs! Bottom line, if a binoviewer is properly made, I don’t think you should be needing to think about adjusting its collimation. Ditto for the precision of eyepiece holders and adjustments.

Just to add an opinion in support of some others expressed above: I’ve found the 17.5 Morpheus to be excellent and also continue to be pleased with the ES68 24mm. I bought a pair of 24mm Hyperions for binoviewing a while back but didn’t keep them long. Granted sig diff in fl, so exact comparison difficult, but, to my eye at least, the Morpheus feels to be in a different league optically over the Hyperions.

Thanks for pointing this out ... Yes, the bino is always going to be used with either the 2x Powermate or the Baader (nominally x 1.7 but really more like x 1.5) GPC. So maybe this config would clean the edges up a little bit. I’d have no reason to want to Barlow it in mono because I already have a a 13mm Ethos, except perhaps, as plyscope mentions, weight - but that’s not an issue at the moment. I have a few eps in the 20s range but nothing longer - a pair of 20mm Smart Astronomy plossls, a pair of 28mm Edmund RKEs and a single ES 24mm. I bought two of the ESs but didn’t like the way they performed in the bino. I kept one and like it on its own; it gets used quite a bit. if I had to pick out my ‘best’ binoviewing pair in moderate fl, it would be the 18mm Tak LEs - sharp, clean, decent contrast, comfortable but not excessive eye relief, no distracting curvature or eye placement issues and very well built. So, I’d like to give the Erfle a go but, thinking head not heart, I’ll probably end up with a pair of the longer LEs or orthos. BW John

Hi plyscope. Many thanks for the useful detail and your advice. (Happy to debate eyepieces but, right now, less keen to talk about cricket ... 😐)

Hi Victor, I do believe that the Baader Zeiss spec prisms are genuine rivals to the Tak or perhaps any other. They are certainly better in terms of scatter and contrast than the AstroPhysics Maxbright mirror dielectric I used to have. When I’d tried the Baader prisms I sold the AstroPhysics. I have both the 2” and 1.25” Baader Zeiss prisms and use them with my TEC 140 which is an f7 apo triplet. The optical quality is exceptional. The Baader system has several other advantages, notably the very convenient clicklock arrangement. I can’t comment on whether scopes below f7 do better with a mirror over a prism. Certainly, at f7, the Baader Zeiss prisms outperform the Baader t2 mirror diagonal that came with the Mk V binoviewer I bought some years ago. Bill Paolini reviewed several diagonals, including, I think, the Tak and both the Baaders. Here’s the link. https://www.cloudynights.com/articles/cat/articles/mirror-vs-dielectric-vs-prism-diagonal-comparison-r2877 ... not to be confused with his review of the BBHS mirror diagonal, which is also on that site somewhere. If you wanted a mirror, those might be worth a look. Hope this provides some useful food for thought 😊 John

Many thanks, Scott42. Pretty much as I thought. I want to like the Erfle because I’m interested in those more traditional designs, but it sounds as though there are better options. I’ve used 10mm and 18mm Tak LEs in the binoviewer which is a Baader Mk V. I also have pairs of the 9 and 12.5mm Tak orthos. I sold one of the 10s - good imv but not exceptional and outperformed to my eye and that of an experienced observer friend on planets in the bino by 8 and 11mm TV Plossls - but kept the 18mm LEs which perform very well indeed. I use the bino with either the 1.7 gpc or, lately, with the 2x 2in Powermate up front. With this latter config, which I now favour, I definitely preferred the view with 18 LEs over that given by a pair of 17.5mm Morpheus’s - good those these were individually. Noted your advice around fov. I’m happy with a moderate fov, so no prob there. Thanks again for your suggestion - I’ll probably end up going with it or perhaps with another pair of the Tak orthos. Appreciate your help. 😊👍🏻

Many thanks, Louis 👍🏻

Does anyone have any experience of this eyepiece please? Thinking of mono and possibly binoviewing. I’ve read some comments online but can’t find much recent or detailed. Thanks.

Agree with Stu’s suggestions on this. I’ve spent a lot of time looking for solid goto alt-az mounts for TEC140 and/or C11. Somewhat different challenges by comparison with an 8 inch Newt, to be sure. I’ve been using the AZ EQ6 mostly in AZ mode for a couple of years and have nothing but positive things to say about it. It spends most of its time on a pier and I swap the scopes on and off as required. I’m always looking for a goto mount that’ll do the job with my scopes but which is significantly more portable - those available seem to fall just short on carry capacity. And generally speaking, I don’t think that’s the right side of the line to be. With either of my scopes, the AZ EQ6 tracks very well even at high mag and points accurately. It’s not an easy ‘grab and go’ but it’s very stable (a consideration with the longer tube Newt) and easy to use. And, if you want to image, you have the EQ mode as well. In my view it’s always better, if you can afford it and weight and luggability are not an issue, to go for the beefier option. Apart from anything else, it allows you to mount something bigger one day if you want to and to mount up more than one scope at a time without have to worry about overloading. The AZ series, incidentally, come provided with the fittings you need to mount two scopes on opposite ends of the AZ axis. Bottom line: I’ve been very pleased indeed with the AZ EQ6 and continue to be so.

Bill Paolini’s review of different diagonals, including the silvered Baader is, imv, a must-read. After using the Baader Zeiss spec 2 inch and 1.25 inch prisms, I sold the Astro-Physics dielectric that I’d bought thinking it would be The Best. It clearly wasn’t in terms of contrast, transmission or scatter. It wasn’t bad, of course, just a shade behind the prisms. The smaller one works exceptionally well with a binoviewer. I’m a fussy observer and I’ve never seen any residual colour when using the prisms at any power. Oddly enough, I sometimes suspected it with the heavily coated dielectric. I couldn’t explain this but speculated that the accumulated depth of the numerous coatings was perhaps sufficient to make some unwanted contribution to the image. Whether or not that’s right, I’m quite clear that the B-Z prisms give superior results. That said, that BBHS mirror does look extremely interesting and I’d love to give one a go ... but there comes a point when the spending has to stop ?

John, somewhat away from the main strand of this thread, but just to reply to your point about the binoviewers. It’s interesting that some people, regardless of experience, don’t seem to take to them. There must be a reason, I suppose. The Baader MkVs that I have have easy adjustment for interpupillary distance and independent focusing for each eye. Maybe that makes a difference. They also seem to be perfectly collimated and perhaps not all binos are. If you can comfortably use binoculars, I think you would be able to use these - that is pretty much how they feel in use. Different eyepieces produce some differences in best eye placement, but nothing dramatic. I’ve had one eyepiece pair that didn't feel well matched. The statement your friend/colleague made doesn’t surprise me that much! The bino adds a dimension that no single eyepiece can provide. Impressions of depth are, of course, illusory. There’s absolutely no question though that they allow you to see more planetary and lunar detail and they can be pretty astonishing on brighter DSOs as well. Reportedly this is because the brain combines information from both eyes. Couldn’t comment on that. I will always use the bino if the object allows. You just see more. As for which eyepieces, yes. I don’t have any fancy ones for the bino - it’s expensive because it’s two of everything! - and you don’t need the wide ones. I did once try a pair of 13mm Ethos’s (it’s that plural again...) in the TEC on the Moon and that was, well, utterly bonkers really. (The other one belonged to a friend) I use pairs of: 9mm Tak orthos, 11mm TV Plossls, 18mm Tak LEs, 20mm Smart Astronomy Sterling plossls and 28mm Edmund RKEs. The last two pairs, like the ones you mentioned, are pretty inexpensive. John E

Hmm, just looked and the TV plossls have jumped a bit in price haven’t they ... and, if comfort is key, then, as you say, not the right answer for you. It does rather depend on what you mean by ‘best planetary’ though. And that’s not a debate to be re-re-re-opened lightly ?. To my eye, the ‘best’ planetary eyepieces have typically been those with few elements, small eye lenses and relatively short eye-relief. Which is not to suggest that there aren’t some excellent general purpose examples out there that will do a great job and be comfortable for all-comers to use. To try and square the circle of your requirements, I like Moonshane’s suggestion of the Delites - the ones I’ve used have been sharp and contrasty as well as undemanding to look through. Bit more expensive though, but they do appear on the s/h market from time to time. If you do go for the Vixen, it would be interesting to know what you make of them - the binoviewer needs regular feeding and it has expensive tastes ? John

Orthos, as others have said, do seem like the clear choice. I have the Takahashi 12.5mm and that is excellent, as is the 9mm, though that’s a bit outside your range. Some of the ‘best ever’ views I’ve had of Jupiter and Saturn were with my TEC 140 under excellent skies in the Canaries with a pair of 11mm Televue Plossls in the binoviewer, albeit, on that occasion, with a compensator in the bino that increased the effective mag. My observing companion and I, both experienced observers, were clear that the Plossls outperformed a pair of 10mm Tak LEs (note, the LEs, not the ‘ordinary’ Tak ortho referred to above). Slight difference in fl, to be sure, but we knew that. As Stu, I think, mentioned, if you can find a way to get into binoviewing for planets, lunar and the brighter DSOs, you’ll see more and maybe never look back. Mono or bino, the TV plossls are very sharp but a touch warmer in tone than the ortho, which is pretty colour neutral. I’ve seen it suggested that this is advantageous in bringing out detail on Jupiter. We were aware of this suggestion at the time and tended to agree. Personally, I’d prefer the cooler/truer tones of the ortho for the Moon and more general observing. So, my first suggestion, if you can run to it, would be the Tak 12.5, followed, if the eye relief isn’t an issue for you, by the 11mm TV Plossl. The 12mm Edmund RKE that I have in a box somewhere is also sharp and contrasty, but I’d choose it third behind the other two. John