JTEC

You might find this advice from Roland Christen helpful - his remarks appear towards the bottom of the page: http://www.darksights.com/Binoviewers.htm He’s saying, I think, that using a Barlow/GPC ahead of the binoviewer is not only convenient in terms of allowing the use of more comfortable eyepieces but strongly advisable to reduce the (small) amount of colour inevitably introduced by the binoviewer prisms. I have the Zeiss binoviewer and typically use it with the Televue 2” x2 Powermate ahead of it. The Baader GPCs, designed by RC to match the Zeiss, also, of course, work well. I do change eyepieces rather than the Barlow or GPC because it’s a lot less fuss - swapping the GPCs involves disassembling the set-up and they’re quite small and fiddly. FWIW, when I do use the GPCs, it’s nearly always the 1.7, which, reportedly, actually yields about x1.5. I use the Tak orthos mainly for lunar and planetary in 18(LE), 12.5, 9 and (despite RC’s advice) 6mm. I also have a pair of the 28mm Edmund RKEs. All of these work very well. The Zeiss is very robust and well-collimated and I think it’s correct that if there are problems in the collimation and orthogonality of any aspect of a bino, shorter eps will make them all too obvious. If I had to choose just two eyepiece pairs it would be the 18mm Tak LEs and the 9mm orthos. If just one pair, probably the 18mm LEs with the option to swap GPCs. This has nothing to do with the quality of performance in the bino - they all work great - it’s just that, with the things I like to look at, they allow most options to be covered and give the best match. Finally, I do urge anyone to persist with binoviewers and work through any issues - they absolutely bring an extra dimension to the viewing experience, not just on Moon and planets but on many DSOs as well.

With the refractor, mono, probably, 13mm Ethos, 10mm Delos and 7mm XW. For lunar and planetary, I almost always binoview with either the 1.7 (gives x1.5) GPC or the x2 Powermate, so that would be pairs (if I’m allowed?) of 12.5, 9 and 6mm Tak orthos, with the 9mm getting the most use. I’m constantly thinking about ‘rationalising’ my eyepiece collection which has built up over many years. (And a new member is on the way - a Svbony zoom at an irresistible £39.99) Apart from the Tak orthos and a pair of XWs, the 7 and 5mm, I haven’t built any sets. Looking at the other end of f15’s question, I have a few high end eyepieces that see little use. Top three among these are the 3.4 Vixen HR, Tak TOE 4mm and 30mm APM flat field. Superb as the first two are, at those sorts of focal lengths, I’d almost always be using the binoviewer. And I just don’t seem to find much use for the 30, except as a finder - if the skies were better here, I’d probably find more use for longer and wider ‘sweeping’ options.

Thank you! Those are all very helpful. It looks as though making something or having it made is the only currently available solution. FLO had expressed an interest in knowing whether there was any commercial source that they might also use, but the only ones I’ve come across are the no doubt good but very expensive offerings from JMI. Thanks again👍🏻

Can anybody help please? I’m looking for a dolly for my 12” f6 Dob. I’ve tried platform trolleys of the sort that B&Q sell but not found them satisfactory. I asked FLO if they could supply one - but they are currently unable to source any and suggested asking the question here, as it might be useful for them as well. Here’s the scope - built by David Lukehurst and pictured by him before collection. David also provided a shroud and built a superb equatorial platform for the scope. Thanks.

I have the 7mm Pentax XW. As others have said, it’s really not a prohibitively big eyepiece - size and weight are not an issue in any of my scopes. Physical and optical quality are absolutely superb. I also had the 6.5 mm Morpheus for a while. I found it to be pleasingly sharp and easy to use. There is so much ‘Morphoria’ going on these days that one hesitates to cast any aspersions in that direction, but, good as it was, I’d certainly put it second to the Pentax.

This is also quite useful. I’m quite happy with Tak orthos and TV Plössls. These are small, lightweight and give high quality images but some people prefer wider field, bigger eye lenses or need greater eye relief. https://agenaastro.com/articles/guides/eyepieces-binoviewers/choosing-astronomy-eyepieces-for-binoviewers.html

This contains some useful general advice from the renowned Roland Christen about eyepieces for binos. His contribution is towards the end of the article. http://www.darksights.com/Binoviewers.htm

Plenty to chose from 🙄. Mostly around mounts: bad carrying practice with equatorial heads like EQ6s but years ago with one of the weighty AE mounts. I never actually drop the mounts in question but, for some time after the AE incident I wished that I had. It mucked my back up for some time. The mount would no doubt have escaped but for a scratch or two. Lowering a mount awkwardly or ‘saving’ it can also put your body through some dangerous extended positions. My old 12.5 inch Meade Starfinder was something of a beast in this regard (though it performed well). It was heavy, fat and slippery, especially when damp. That gave me a few tweaks. And, of course, big Dobsonian bases can catch you out, as you do the straight leg waddle but in a dodgy extended position. So can lowering heavy Dob OTAs into their base, especially if you don’t slot in the bearings first time and have to support and manoeuvre the weight of the tube for longer than you planned for. My ‘worst’ scope accident was when I stupidly failed to properly secure the legs of an early Berlebach tripod carrying a GPDX. It collapsed like a shot giraffe and the mount cut into my forehead as it fell, leaving me with a scar. Nowadays I am much more careful!

Andrew, not wishing to be in any way confrontational, but I do think that’s a highly questionable generalisation. 🙂

Agreed, Louis. It is an extra bit of faff. Like you - and I guess this is my answer to the OP’s question - I don’t use them all the time. I was referring to being able to coordinate the view from two eyes. If something is skewiff in the system it won’t be possible, regardless of the skill of the observer, and in the BV optical and mechanical train there are quite a lot opportunities for wonkiness.

I don’t feel it’s quite that cut and dried. Absolutely, imv as many others’, hugely advantageous for lunar and planetary. But I’ve had some wonderful views of brighter nebulae, especially M42 with binos through both my TEC and more especially, thanks to the aperture, a C11 I used to own. Without question more immersive than mono. Globulars are also a great binoviewing target. Again, to my eye, improving on mono, thanks to that illusion of depth and 3-dimensionality. The 18mm Tak LEs have been mentioned a couple of times - fwiw these are one of my absolute favourite binoviewing eyepiece pairs. Another thing to consider is that you don’t need pairs of expensive eyepieces. I use the Tak orthos; the BCOs and lots of others should also work pretty well I think. There’s probably a little bit of a knack about using binos but in terms of viewing technique I honestly don’t feel it’s much different from using ‘ordinary’ binoculars. What is different is that there’s a lot more system to be collimated and kept orthogonal, starting from the scope, through the bino and all associated prisms etc and ending with the eyepieces and the accuracy and security of their seating. And potentially at high mags where errors too are magnified. I don’t have any real evidence for this but I’m convinced that it’s this kind of thing that’s at work when people find binoviewers ‘difficult to get on with’ but are happy sweeping around with their 10x50s. Anyway, some food for thought 🙂

This must be the first thread I’ve encountered anywhere ( though I’ve not dug into CN lately) where the quality of the TEC140 is being picked at 😂. I’ve owned #165 with the FT focuser from new. It is an absolutely marvellous scope. Es Reid tested mine and confirmed this. I don’t know if the fluorite version is any better visually - I’m at a loss to see how it could be. Comparing fairly similar competitive scopes is never likely to be an objective exercise because user tastes differ, eyepieces perform differently in different scopes, ergonomics, feel, etc etc. Too many variables personal and instrument related. It beggars belief (if you’ve spent time with one) to hear the TEC140 described as ‘lacking’ something 🙄. That said, it is ‘only’ a 5.5 inch scope and, beautiful though its images are, it’s inevitably outperformed in terms of resolution by decent bigger scopes. Given that it’s optical quality is pretty much as good as it can get (see Chris Lord’s analysis/review), I personally take evaluations of smaller telescopes outperforming it visually with a pinch of salt. Other factors than optical have to be involved. And, by the way, where are all those leaky oil-spaced triplets dripping all over the place?! 😂

The Planet is certainly beautiful and very solid but heavy. I bought it for my AZ100 and TEC140. If buying again, I’d probably go for the Uni

Sorry about that - please see repost 👍🏻

Here’s another go with Yuri Petrunin’s eyepiece choices for the MkV binoviewer and the TEC refractors. Hope it works this time!

For interest, here’s Yuri’s choice of eyepieces for bino and TEC140.

Hi Martin, I use a Zeiss bino with my TEC140. (Yuri Petrunin of TEC opts for a par of 10mm Delos with that scope.) I have one 10mm Delos and find it a standout eyepiece but can’t quite bring myself to fork out for a second …. My go to eyepiece pairs are the 18mm Tak LEs, which I much prefer to the pair of 17.5 Morpheus I tried (I kept one), and the 9mm Tak ortho. (Plenty of people, of course, do like the Morpheus in the bino role and supposedly they were designed with that in mind.) I also have Tak ortho pairs in 12.5 and 6mm. They are all excellent. The 18mm LE and the Tak ortho 9mm get the most use in the TEC and in my 12” f6 Newtonian. I always use them with either the x1.7 (gives about 1.5, reportedly) GPC or the x2 2” Powermate ahead of the prism. Hope that’s some use, from one Surrey Hills dweller to another.

Me too. FWIW, I’ve tried most of the contenders over the years and have settled on the Televue Bandmate OIII. If there’s such a thing as a ‘best’ such filter, it would be my suggestion. Just to muddy the ‘UHC’ waters a little, you might like to spare a thought for the Omega/DGM NPB filter, which, along with many other observers, I like a lot.

I think it depends so much on the item that percentages are hard to give. I thought recently about selling my hardly used Vixen HR 3.4 eyepiece - letting it go for 60% of the purchase price, that’s to say £130 seems a bit too generous to me, given that there is also postage and insurance to be deducted from that. On the other hand, I wouldn’t feel justified in asking as much as 60% of the original value for a rickety 15 year old Dobsonian with resident spiders. I’ve heard 75% now 60% … personally, when I sell things, I start by removing the VAT (there is an argument for not doing so, of course), then make what I think is a fair deduction for condition. I never deliberately over price things in the hope of getting more than they’re worth; equally, I do ask what I honestly think they’re worth. I don’t do this to be saintly - it just has the advantage of putting things on a rational, arguable basis. In the end though, the bottom line is always whether anyone actually wants to buy what you’re selling!

Like John, I really miss shared observing events. But any visit to the shops round here shows that ‘common sense’ can’t be trusted as a way of ensuring Covid-responsible behaviour. Personally, I wouldn’t be too worried about being with a few fellow observers I knew out in a field, using my own scope. But we know the virus is transmissible by the eye-route, so sharing scopes, and specifically eyepieces, sounds like a very bad idea indeed. Wiping eyepieces doesn’t sound very practical; whatever the stuff used, I wouldn’t want it near my eyes and I can’t imagine it would do the eyepieces much good either. So, for me, it’s still a non-starter. Helluva shame though … .

As others have said, should work without a problem. I routinely used my Baaders with Baader 1.25 prism on C11 with 2x Powermate ahead of the bino. No focus issues at all. And absolutely worth it. The views of many objects - the Moon, for example, and brighter DSOs were so engaging and immersive that, for these targets, I never bothered with mono viewing again. Every reason to think that you’ll soon sort this out - hope so.

Here’s something else to scramble your brain ... in a good way 🙃 https://www.cloudynights.com/articles/cat/user-reviews/24-26-mm-eyepiece-comparison-r2651 FWIW, I have the Ex Sci 24mm 68* and like it a lot.

Just as John says, the Powermate seems ‘invisible’. Actually, I have the 2” and mostly use it ahead of the binoviewer. I don’t generally ‘Barlow up’ longer eyepieces to achieve shorter focal lengths, except to experiment, usually preferring to use the shorter focal length eyepiece itself. But that said, some eyepieces benefit from being Barlowed (though the Powermate isn’t exactly a Barlow), one example, quoted by Bill Paolini, is the 10mm Burgess Ultra Mono. And while some eyepieces in some systems respond very well to Barlowing and some less well, there need be no fear, imv, that a modern, high quality Barlow or Powermate, by introducing ‘more glass’ into the train, will inevitably degrade the image. There are more bits of glass in some of our top performing eyepieces than under the counter and behind the bar at the Badger and Candlestick.

I can’t join in the levity around this. Most SGL members will have read about the global increase in overall sky brightness due to the cumulative effect of the stuff that is already in orbit. The Starlink, OneWeb and other satellite megaconstellations that have already been launched, or are scheduled and anticipated, will be intrusive in unprecedented numbers, frequency and scale. They will contribute significant polluting light on their way up and down and once in operational orbit. Elon Musk promised zero impact on astronomy but the mitigation measures that have been trialled so far haven’t come close to achieving this. The plan was to keep the brightness below mag 7 in orbit. Mag 7 is not ‘faint’ - it’s bright enough to be naked eye visible from the most precious dark skies we have and certainly bright enough to degrade data for professional and amateur astronomers. For amateur imagers, this means some added nuisance - for professional astronomers working scopes like the Vera C Rubin, things are more serious. There’s no question that the megaconstellations will contribute to degradation of the night sky; the question is whether their supposed benefits make that worthwhile. Personally, I don’t buy the ‘it’s for the good of mankind’ argument and believe they have nothing to do with altruism and everything to do with the exploitation of markets. Others will see it differently. For now though, I would urge lovers of the night sky of all sorts and persuasions, to get over the immediate fascination of seeing these things moving against the stars. What we’re seeing now is just the thin end of a gigantic wedge - those little lights in the sky are harbingers of very bad news for ground based astronomers and for anyone who values the beauty of an unspoiled night sky.

I’ve actually been very impressed with the 6.5 Morpheus in the TEC 140. During the recent Mars opposition, I spent a lot of time cycling through various eyepieces in that sort of range, including the 5 and 7mm Pentax XW, the 6mm Tak ortho and 9mm Tak orthos x1.5 in the binoviewer. The Morpheus gave a distinctive, sharply etched view that separated it from the others. I’m not, of course, saying it was ‘better’ - but it certainly, imv, belonged in that company. All of the eyepieces and combos gave excellent views and each differed a bit in character and feel from the others. Together they built a picture fuller than anything just one of them could supply. I suppose my point is that, within reason, slight inconvenience in use and things like whether the edge is super sharp when you’re looking at the middle are well down the list of criteria to select eyepieces by. There are several things I don’t like about the 13mm Ethos in actual use, for example, but I’ll put up with those. I prefer the comfort, form factor and handling of the XWs to the Delos but I prefer the freedom from colour of the Delos to the XWs - both are terrific eyepieces. When we have so many eyepieces that deliver the ‘core business’ so astoundingly well, we can get very nitty-picky about peripherals. 🙂