Linear Binoviewer (TS Optics) with Lunt LS50DS

[niallk]

Hi,

I've been eyeing up a "Linear" Binoviewer for reaching focus primarily in my lovely lil' Lunt LS50DS, but also potentially for use in my Obsession 15" Classic.

I do have a Baader Maxbright BV 1st gen), which was a revelation for plantets / moon in my SW 250px - before i donated that scope to someone.

Unfortunately the Maxbright won't come to focus in the Lunt... hence I've been intrigued by the promises of a Linear Binoviewer... plus the Maxbrights + GPC just dont play well with the 15" dob either.

Unboxing - comes in a rugged & oversized plastic case: pluckable foam for storing pairs of EPs - very good!  The BVs feel heavy, solid and give the impression of being well made: no issues.

I have the Moonlight dual speed focusser upgrade on my LS50DS.  There's an undercut on the BV which means it waggles in the compression ring fitting in the Moonlight 😖  Not to worry: if i pull it out and clamp on the smooth sides i can still reach focus - phew! 😅

I popped in 2 TV 15mm plossls & roughly adjusted the inter pupil distance.  I normally observe with my right eye, so focussed with the Moonlight for my left eye, then used the diopter adjustment on the BV for my right - back to a helical focusser after purchasing the Moonlight! 🤣

Voila! No issues merging, but adjusted the IPD a little more.

My first impression was great i see a merged image, but it's a little soft.  I iterated on focussing with left eye, then right, the both together via the Moonlight.  It takes a little patience, but i got to a point where I'd say the views were almost as sharp as mono - and was removing and comparing with a single mono 15mm.  So far I think the views are not quite as sharp - much more complex optical path, but certainly it is very nice to view through both eyes!

It's heavy... and caused a little focusser slip with the sun at its highest: had to tighten the lock screw a little for extra friction.

I'd say I'm not immediately a convert as i was when i tried my Maxbrights in my 250px on Jupiter.  However, i will give them a few more sessions... i really want them to become my default choice, but i love that fine crisp detail achievable mono with a tv plossl and the fine adjustment with the Moonlight.

We'll see... will report back!  Will also test on the moon in my 15" when i get a chance 😎

Edited June 6, 2023 by niallk

[MalcolmM]

This mirrors my experience exactly! Tricky to achieve best focus and the image is softer than with mono viewing. I found the same effects with lunar viewing and they do not tighten well in the Tak prism diagonal. Like you, definitely not the game changer the Maxbrights were for me.

That being said, I persevered with them and it does become easier to get a decent image through them with practice. And it's much more relaxing to use binoviewers than mono. 

Malcolm 

[niallk]

Very interesting to hear Malcolm!

[F15Rules]

Interesting review Niall, thanks for posting and I look forward to further updates as you use the BVs even more.

I have looked with interest at Linear binoviewers in the last 12 months, but my heart was really set on the new Maxbright IIs, which of course were just impossible to buy for much of the past couple of years.

Having recently managed to buy an MBII, the truly awful night time weather in Lincolnshire this year so far has not yet allowed me to properly evaluate the new Maxbrights: however, what I can say already is that Baader have listened to their customers regarding the ergonomic issues which IMHO held back the original Maxbrights' performance.

These include the fiddly 3 way eyepiece holders, which proved to be an exercise in frustration for me with the Mark 1s, the limited clear aperture which meant longer focal length eps could vignette and also limit the brightness of images as compared to single eye viewing.

I'm pleased to say that the new clicklock type eyepiece holders and the increased clear aperture of the new MBIIs, PLUS their superb new T2 connectivity , have fully addressed the failings of the old model.

It would be fascinating to see a head to head comparison of the Linear Design with the new Maxbrights..

Dave

 

Edited June 7, 2023 by F15Rules
Typo

[Highburymark]

I also found your report interesting Niall. I couldn’t make any binoviewer work with the LS50 so the Linears are a real breakthrough. Even with slightly soft images, I can imagine they still offer great benefits. You might find that you use them for full disks and low power views, then go back to single eyepieces for closer details. Love the red Moonlite - no longer made sadly, but perfect for the LS50.

[MalcolmM]

4 hours ago, F15Rules said:

It would be fascinating to see a head to head comparison of the Linear Design with the new Maxbrights

I compared the Linear with the Williams Optics binoviewers somewhere on this forum! I found the view through the WO better. I also find the view through the Maxbrights better than the WO. 

So in my experience, the Maxbrights are much better visually than the Linear. I really only use the Linear in my Lunt because I cannot get the WO or the Maxbrights to come to focus in the Lunt 50.

But you make me think I should do a comparison between all three, particularly now I have got a bit more experience using the Linears!

Malcolm 

[Franklin]

I'm on the fence regards the Linear viewers, on the one hand they will get native focus which is a plus for lower power binoviewing but on the other hand, they have a reduced clear aperture so vignette with long focal length eyepieces for low power. So it's kind of, one step forward, two steps back for me. Either way I'm sticking with the Maxbright II's as they are easily the best binoviewers I've ever had. I've tried the WO, the original Maxbright, budget OVL and Bresser Linear.