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Optolyth TBS-80 Baader Zoom Query (1 Viewer)


Optolyth TBS-80 Baader Zoom Query

Hi! I picked up my first scope last week, an old (W.Germany Embossed on it) Optolyth TBS-80 Fluorite Lens with 30xWW EP, in great condition. Obviously nothing to compare it to, but it seems pretty great! Anyway, before purchasing, I scoured the threads here for info on it and it seems that I can use a Baader Hyperion Zoom lens with it, alongside some o-rings. (This seems a better choice than the Opticron HDF Zoom - wider view etc.?)

My questions is, can anyone say whether the info below from Baader, who seem super-helpful, is correct, please? I was trying to find a more robust solution to the o-rings...

"Do you need to adapt this to a M37 male of female thread? The only M37 adapter we have is this one with M37 male thread https://www.baader-planetarium.com/en/baader-dt-adapter-i-t-2--m37.htm. To adapt this adapter onto the Hyperion Zoom Mk IV, you would also need our 2"a / T-2i zero-length reducing piece #2454833 (https://www.baader-planetarium.com/en/2"a--t-2i-zero-length-reducing-piece-(no-optical-height).html) as well as our T-2 / T-2 inverter ring #1508025 (https://www.baader-planetarium.com/en/baader-t-2t-2-inverter-ring.html)

If it is correct, will it cause any focussing issues by making the EP too far away (not up on the technicals, as you can see!)?

Also, would a Hyperion Zoom 2.25x Barlow lens, be a good thing and would it also attach/focus etc?!


We are mainly thinking wildlife viewing, but having made out the rings on Saturn the other night, anything that improves this/sky watching stuff would be most welcome!

Thanks in advance, Mark.


Well-known member
Hard to say.. The Baader MkIV has been designed to work with many spotting scopes,so the eyepiece mounting hardware doesn't take any room really..The instructions they are giving to you, are based in the use of the 2 inch collar.. The three adapters that they offer in the suggested plan, are to get a male 2 inch thread to fit the zoom.. I think is all gonna depend in the depth of the T2 inverter.. I can't open the first link, but If the First adapter is M37 to T male threads, then you won't even need that and it will most likely work.. I have a bunch of baader adapters, let me see what i have, i ll let you know


Well-known member

the Barlow lens would increase magnification by 2.25x and would change the zoom range from 18-55x to 41-123x. It needs a very good example and good seeing to make use of that,

Also the Barlow is used as a 1.25" nozzle and will not necessarily work with the planned adaption via the m37 to T2 adapters due to lack of space inside the body. It might work with the following adapter but whether it comes to focus the is not sure either.


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Well-known member
That is the one i figured it was.. Yes with that one you would need the inverter.. İt seems like you are starting to get close to the límit of the focal point, even with the adapter only, so if you push a bit more with the T2 inverter, the chances of not reaching focus are increasing. There seem to be other adapters for M37.Baader makes some to hold 37mm filters that show a more narrow profile.Maybe we can figure a more sure way to adapt the zom... I do have the 2 inch to T2 baader adapter if you need it, and some others..ill post links to other M37 when i find them..


Great info, thanks guys. So, I’ll give that part a miss then, thanks Joachim.

Hmmm, that was what was concerning me...spending £60+ on some adapters seems a little frivolous, and the fact that they may not work, is a little worrying...especially with the good lady keeping a watchful eye on the project!

To get some idea of the tolerance available, could I unscrew the present EP or indeed buy the Baader Zoom and then test how far away from the scope it still works? And perhaps more importantly, if this was an idea, how would I test if it was still working?!

As you can see, not really sure what I’m doing this end! Thanks again for taking a further look and also for the offer of some parts - are they the one Baader suggested? Seems you may be hatching an alternative solution also...!

Many thanks,



Got you. Did have access to a 3D printer, but not anymore. I guess there are places that print though. I’ll have a look...


Well-known member
The probability of focusing with the Baader zoom, depends on the age of the scope (see the serie numbers and the adapters mentioned at http://www.pt-ducks.com/cr-telescopes.htm#Test%20of%20100mm%20telescopes ) - older scopes have an internal ring that don't allow the 1.25" barrel to get in, so don't reach focus...
Adapters based on the 2" barrel on the Baader zoom will not reach focus.
The 2.25x barlow increases too much for terrestrial use and you need an extra 1.25" extension tube https://www.astroshop.eu/extension-tubes/baader-extension-tube-dt-4-verlaengerungshuelse-31-8mm-a%23-1-af-/p,10582 since the 1.25" adapter that comes with the barllow seems that was designed to protect 1.25" astro-diagonals but don't allow it to reach focus with spotting scopes accepting 1.25" eps...


Thanks David, great info.

I have read a couple of threads (https://www.birdforum.net/showthread.php?t=314199) where people have removed the various adapters for the zoom and it has fitted/worked, so I am hoping I can do the same...! They used an o-ring to attach, or indeed some tape, so it seems from what you say, this is my only option, as any adapters will move the EP to far away.

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