Product Questions and Answers
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I wonder if someone can help me. I have the original Binoviewers Maxbright and I want to change the screws (6) that hold the eyepieces with "knurdle" kind, easier to change eyepieces. Can you please tell me the size, someone said they are M4. But not sure. Are they metric? Coarse thread, etc.
Really appreciated, I have many of your products and very happy with them.
Also, have you any idea when they will be available for sale again?
Wide-angle eyepieces are available only in shorter focal lengths, otherwise they would show the inner walls of their own 1.25" sleeve - they can't show a larger portion of the sky than the 36mm-eyepiece mentioned above, they only magnify it higher.
So, there are no practical limitations, all 1.25" eyepieces work.
You may notice some vignetting when taking photos through an eyepiece, but with the eye, there is no problem.
We can't give a specific date when the binoviewer will be available again - tis depends on production and quality control, and due to the distortions caused by Corona, things have become pretty much unpredictable.
However - we have worked more than four years on making this product irresistible and we did put all experience from 35 years of making binocular viewers into this latest bino of ours. This is NOT just some astro-modded operation-microscope-bino from Taiwan or China. Our product is the smaller version of the Mark V, were we had bought the design and production drawings from Carl Zeiss Jena 25 years ago.
We do tender components for our products worldwide and we do the assembly and QI here in house. If you were to read through the manual for this product (see "Downloads" tab) it ought to become obvious that no one else has given it more care to make this as universal in usability as ever possible. The development costs were too huge to fail. We dearly hope people will see this - at the spot - when using this product the first time.
At high magnifications with a smaller field of view, there isn't too much of a difference, except perhaps a little bit in direct comparison because of the coating.
But placing a barlow lens in front of the binoviewer will highly increase the magnification facor, as the binoviewer has got an optical length of ca. 110mm, plus the length of the T-adapter of the barlow lens.
You can find some information about calcutaing the magnification depending on the distance between eyepiece and barlow lens in this PDF:
Please excuse me if I don't do the math, but the resulting magnification factor should be somewhere between 3x and 4x. So, it may work, but the magnification may be too high.
Please also note that our glasspath correctors are similar to barlow lenses, but not identical. If you already have the Hyperion Barlow, you can just try it out; otherwise we'd recommend the purchase of a glasspath corrector, which also works better against chromatic aberrations which are introduced by the prisms when you use a fast telescope.
1. A female T-2 thread to adapt onto most common photographic equipment
2. A Zeiss ring-dovetail as it has been established by Carl Zeiss for more than 50 years.
We will soon publish an extensive manual that shows the multitude of accessories that we recommend to combine with the MB II in order to adapt this onto most every telescope with the shortest possible optical length.
We cannot equip the MB II with the star diagonal that you certainly would need with your refractor in order to have a convenient way of looking through the telescope, because all users of Newtonian telescopes could not make use of this star diagonal. Accordingly it will be a matter of the customer or the dealer to help finding the appropriate adapters or star diagonals for the telescope in question and most of all, to enable this adaptation without wasting precious backfocus. This is the reason why we have developed a multitude of T-2 prism star diagonals with T-2 threads on both sides. Because you could choose for your refractor whether you want to use a 2" nosepiece to put it in front of the star diagonal or whether you opt for a 1.25" nosepiece.
So please have a bit more patience until we publish the MB II manual and check our website for star diagonals. Because furthermore we are preparing an extensive document to explain all the differences and benefits of our various star diagonals in exhausted detail, this will also be published within the next month.
- CELESTRON OTA C9.25 XLT
- adapter SC-T2 BA-2408160 (Optical Path (OP) : 16 mm)
- T2 adapter AC0105 (Pierro Astro Manufacturer) with embedded VIP 2x barlow lens from BA-2406101 (OP : 24 mm)
- T2 ADC (Atmospheric Dispersion Corrector) (Pierro Astro Manufacturer) (OP : 22.5 mm)
- T2 Maxbright mirror diagonal BA-2456100 (OP : 43 mm)
- GlassPath corrector 1.7x BA-2456316 (OP : -40 mm) (some datasheet specs is -65 mm ??)
- Maxbright II binoviewer BA-2456460 (OP : 110 mm)
- Morpheus eyepiece (6.5, 12.5 or 17.5 mm)
The overall optical path reach more than 175 mm, well above C9.25 CELESTRON back focus data (139 mm).
Is computation wrong ? and otherwise, what change in set up I need to do ? (removing GPC ?)
Do not think too much about the ideal back focus distance of your telescope, as both Barlow lenses and GPCs move the focus point and change the back focus.
You'd have to ask the manufacturer of the ADC if it is better to place it befor or behind the star diagonal. We'd probably recommend to use only the GPC in front of the bino viewer and to skip the additional Barlow lens.
All the best,
In this case, you can place the glass path correctors 1.25x # 2456314, 1.7x # 2456316 and 2.6x # 2456317 in the nose piece; the GPCs for the Zeiss ring dovetail do not fit then.
We have decided to opt for the T-2-connection, as you can then screw the bino-viewer directly onto a T-2-star-diagonal and use a much shorter connection than with an eyepiece holder between bino and star diagonal. This way, you can easier reach focus, don't need a GPC with a high magnification, and can easier use low magnifications. The T-2 star diagonals can also be used with a 2" or 1.25" nose piece in any standard eyepiece clamp.
We have described the different adaptations in the manual of the MaxBright II, which you can find in the download section of the product or directly at
You can only use 1.25" eyepieces, although our Hyperion Aspheric 2" eyepieces come with adapter so that they can be used as 1.25" eyepieces - if there is sufficient back focus.
We always recommend to measure your available backfocus first (with your existing star diagonal, but if possible also without it), so that the necessay adaption can be found - often, there are cheaper sets availableht an if you have to buy every item seperately.
For highest magnifications, you may want to remove the Alan Gee and use a GPC instead, although at f/10 a GPC may not be necessary at all.
> celestron sct 6” or 8” hd
> Baader Ultrashort SCT T-Adapter
> Baader Planetarium Click-Lock Eyepiece Clamp (# T2-08)
> Baader 1.25" T-2 Nosepiece
> Baader T-2 / 90° Baader Roof-Prism with BBHS
> Baader Planetarium Click-Lock Eyepiece Clamp (# T2-08)
Do you recommend inserting the Universal Alan Gee II between Roof-Prism and SCT or MaxBright and Roof-Prism?
And it seems I also need another Baader 1.25" T-2 Nosepiece to mount MaxBright to my original Eyepiece Clamp, right ?
We recommend to attach the Alan Gee close to the binoviewer as described on page 9 of its manual https://www.baader-planetarium.com/en/downloads/dl/file/id/213/product/1197/baader_alan_gee_ii_telecompresor_shapley_lens_f_5_9_manual_and_applications.pdf
and the Universal Alan Gee as described in its manual at https://www.baader-planetarium.com/de/downloads/dl/file/id/1611/product/4550/universal_alan_gee_ii_uag_ii.pdf
It is to mount on a celestron 8 telescope and 120ED. Thank you ;)
The alternative to the 32mm-prism would be the Baader T-2 Stardiagonal (Zeiss) Prism with BBHS ® coating (T-2 part #01B) # 2456095 with 36mm prisms, which we recommend for the larger Mark V (Giant) bino-viewer, because that binoviewer has got larger prisms than the Maxbright II. But with your telescopes and the MaxBright II, the smaller 32mm-prism should be fine.
I also have a 70mm SolarMax III. Will I be able to use it with that? Again what accessories will I need?
Furthermore we recommend to take a look at our PDF: Manual and Recommended Use of Baader Star Diagonals (T-2 and 2"):
Unfortunately we don't sell the SolarMax III and don't know its thread sizes and most of all the available backfocus (but we strongly assume that it is very much too small). So we cant comment here on required accessories or functionality.
Then you can let the BBHS onto the tube, also you´re able to mount a glaspathcorrector like this for example:
Please take a look to the description for this corrector about the reasons why it should be used.
- the backfocus length of your telescope
- a 2" or 1.25" nosepiece, if you can't use the T-2-thread of binoviewer to connect it to your equipment
- maybe a star diagonal - we recommend our T-2-prisms because they allow for a very short adaptation and save valuable backfocus
- probably a glasspat corrector to reach focus - we recommend the 1.25x, as it also removes colour fringes at faster telescopes.
You need to determine the backfocus of your telescope either from the back of the 1.25" or 2" eyepiece clamp or a T-2-thread, if available. You can do this e.g. by pointing the telescope with fully retracted focuser at the moon. Hold a piece of paper behind it and measure the distance at which you can see a sharp image of the moon - that's the available backfocus. Attach all necessary accessories to the telescope when determining the back focus.
If you intend to use it with a star diagonal, you have to include this, too. The available backfocus must be longer than that of the binoviewer with all accessories.
For example, the shortes combination would be
- 2"/T-2-adapter/nosepiece #2408150, optical length 2,5mm
- T-2/90° star diagonal #2456005 with 32mm-prism, optical length 35mm
- MaxBright II Bino in T-2-configuration, optical length ca. 110mm (give or take a little bit for diopter compensation and focal plane of the eyepieces)
then you need a backfocus of at least 147,5mm.
Then you can choose a matching glasspath corrector to reach focus, and/or replace the star diagonal. The glasspath correctors save you back focus, but the also increase the magnification by the given factor:
Glasspathcorrector 1:1,25 for Baader-Binoviewer with T-2 thread (MaxBright II and MaxBright) # 2456314: Backfocus gain 30mm
Glasspathcorrector 1:1,70 for Baader-Binoviewer with T-2 thread (MaxBright II and MaxBright) # 2456316: Backfocus gain 65mm
Glasspathcorrector 1:2,60 for Baader-Binoviewer with Zeiss ring dovetail (MaxBright II and Mark V) # 2456317: Backfocus gain 120mm
So, if you choose the 2.6x corrector, you only need about 28mm of backfocus, but the magnification increases by factor 2.6. We always recommend at least the glasspath corrector 1.25x, because they also remove the colour fringes which are introduced by the prisms inside of the binoviewer at fast telescopes (faster than ca. f/10).
The glasspath corrector is mounted inside of the star diagonal, our T-2-diagonals are prepared for it. If you use your own star diagonal, you can mount 2"/T-2-adapter #2408150, optical length 2,5mm or Baader Nose piece 1¼" / T-2 (T-2 part #14) # 2458105 in front of the binoviewer and insert the glasspath corrector there.
Using a 2" diagonal will put any binocular viewer in too large a distance from ideal focus of an SC.
As a result you will vignett the beam without noticing - means your front opening of the optics is being effectively reduced and stars appear dimmer than they are, compared to their appearance when all distances between the tube end and Viewer were minimized. However - people will blame the binoviewer of "being too dim", wheras the dimming is the effect of having lost an inch or so of their telescopes aperture.
For this reason we have developed the T-2 Star diagonals - which are absolutely made to not cause any vignetting - and to put the (Baader-)binoviewers as near towards the telescope tube a ever possible.
Pls take the time to do your own research - google for: SC-vignetting w. binocular viewer.
A quick changer is recommended, so that you can more easily rotate the binoviewer into a conveniant position.
There are two versions of the Newtonian Glasspath Corrector:
2" Glasspathcorrector® 1,7x for Newtons # 2456300
does not have a thread - it fits onto the Zeiss Microbayonett of our MaxBright and Giant binoviewers.
I think you have
2" Glasspathcorrector® 1,7x for Newtons incl. T-2 change ring # 2456301
This is the same part, but it includes the Microbayonett (Baader (TCR) Hardened Steel T-2 ChangeRing (T-2 part #07) # 2456320), which is already installed on the MaxBright II binoviewer. If you have #2456301, then it is the shiny ring with the T-2-thread - it can be removed by opening a small clamping screw next to it. In this case, you have bought one T-2 change ring too many.
Baader MaxBright® II Binoviewer
"Supercharged" by design
The MaxBright® II Binoviewer incorporates the knowledge aquired during thirty years of building astronomical binoviewers. It is superior to cheaper models in many details.
- The housing of the 27mm large prisms is made with our own die casting moulds, using Carl Zeiss production drawings. The non-slip synthetic leatherette finish provides extra grip when holding the binoviewer with heavy eyepieces in your hand.
- On the eyepiece side, the newly designed, self-centering Clicklock® eyepiece clamps with diopter adjustment are immediately noticeable. Thanks to the ergonomic design, you can blindly distinguish between clamping and diopter compensation even in the dark. The inner parts are made of stainless steel for maximum stability. The high-quality eyepiece clamps are only the last part of the precisely collimated optical system, which is designed for highest magnifications. This is the only way to achieve the almost three-dimensional image and relaxed observation expected from a binoviewer.
- All optical surfaces of the Maxbright® II feature a 7-layer multi-coating. The prism chairs (mounts) of the prisms are constructed like those of the Mark V Großfeld (Giant)-Binocular (#2456410 , € 1425) . The clear aperture is 26 mm on the telescope side and 25,5mm on the eyepiece side – even our 35 mm eudiascopic eyepieces are illuminated without vignetting. In comparison to models with smaller prisms you can see a much larger part of the sky at the same magnification – similar to our Mark V Großfeld (Giant)-Binocular (#2456410 , € 1425) .
- On the telescope side, either a T-2 cap nut or a dovetail ring with original Zeiss micro bayonet are available – both connection options are included in the scope of delivery and allow a very compact adaptation to all common threads as well as our T-2 prisms and mirrors. Compared to fixed nosepieces, this effectively saves a lot of backfocus. The MaxBright® II is compatible with all Baader Glasspathcorrectors. According to optical calculations by Carl Zeiss, these correction lens systems shift the focus outwards so that you can still reach focus despite the approximately 11 cm back focus (the required inward travel of the focuser) of the binoviewer. They also compensate for the colour error that would otherwise be introduced through the prisms when using telescopes between f/4 and f/7. Glasspathcorrectors are not simple Barlow lenses, even if they resemble them. For this reason, in Germany the name Glaswegkorrektor® is a protected trademark by Baader Planetarium.
In combination with a lens telescope or a Schmidt-Cassegrain we recommend the Baader T-2 Stardiagonal (Zeiss) Prism with BBHS ® coating (T-2 part #01B) (#2456095 , € 243) or the Baader FlipMirror II Star Diagonal (#2458055 , € 228) , to achieve a compact telescope adaptation. In addition, you can then choose a matching Glasspathcorrector
To select the right Glasspathcorrector, you need to know the backfocus of your telescope. You can read how to do this in the Manual of the Maxbright® II Binoviewer.
For Newtonians,we recommend either the large 2" Glasspathcorrector® 1,7x for Newtons (#2456300 , € 205) or the Glasspathcorrector 1:2,60 for Baader-Binoviewer (#2456317 , € 132) .
For SCs or lens telescopes we recommend either the 2" Glasspathcorrector® 1,8x for Refractors and SC's (#2456305 , € 195) or the two T-2 Glasspathcorrectors Glasspathcorrector 1:1,25 for Baader-Binoviewer with T-2 thread (MaxBright® II and MaxBright®) (#2456314 , € 122) and Glasspathcorrector 1:1,70 for Baader-Binoviewer with T-2 thread (MaxBright II® and MaxBright®) (#2456316 , € 127) . The 1.25x Glasspathcorrector is used on lens telescopes mainly for removing the colour aberrations, which would otherwise be introduced by the long light path through the prisms of the binoviewer.
You don't necessarily need a Glasspathcorrector for Schmidt-Cassegrains with f/10. Especially for lower magnifications and thus larger fields vof view, the Alan Gee Telecompressor Mark II (T-2 part #20) (#2454400 , € 275) is more interesting: It shortens the focal ratio to ca. f/5,9, which gives you a brighter image and a larger field of view. So, a C8 almost becomes a rich-field telescope – for comfortable observations with both eyes open!Repair requests for the classic Maxbright I Binoviewer
For many years we produced and distributed the Maxbright I Binoviewer. Now that the product has been discontinued for several years and production has been completely switched to the Maxbright II Binoviewer, we can no longer offer repairs on the Maxbright I Binoviewer at reasonable cost. However, to ensure that you continue to enjoy your equipment, we recommend that you contact the german company www.fernrohr-service.de for maintenance and repair.
Binoviewers and accessories
Baader Planetarium has more than 30 years of experience in building binoviewers. Therefore we do not offer simple modified microscope binoviewers without further accessories, but complete system solutions.
With monocular vision, your brain can only use a fraction of its "computing capacity". In fact, there is a kind of "emergency mode" in the brain so that even image information obtained with one eye can be distributed to both halves of the brain, but the brain has no way of correctly interpreting the "image errors" and above all the "nerve noise" that inevitably occurs during energy transport - just like with a CCD image!
Just as the user of a CCD camera or webcam superimposes several images in the computer, i.e. "stacks" images, the brain can also superimpose the different information from both eyes during binocular vision and in this way - each time in milliseconds - eliminate the imperfections that are not part of the real image.
So it is no wonder that after observing with one eye for a few minutes, you will have to take a rest that your brain demands because it is simply overloaded by the extremely concentrated viewing. In binocular vision, this problem does not exist! You can look as long as you want and remain relaxed. Even with severely impaired vision in one eye, the reduced tension results in an enormous gain in observation quality.
One often hears the criticism that using a binoviewer would split the light into two visual channels and that only 50% of the light intensity reaches each eye. This argument prevents many people from trying out for themselves what a revolutionary effect binocular vision has. But what is forgotten is that 50% of the light reaches each eye and that the energy from both eyes is "reunited in the brain" (more precisely, in the back of the head).
What you then see is by no means 50% darker than it is claimed. The real gain is only visible for someone who has tried it out for himself and has familiarized himself with this kind of seeing for a few minutes. Ultimately, the object doesn't look darker, but becomes visible effortless, more detailed and - more beautiful.
|Net weight (kg)||0,595|
|Aperture (mm)||Teleskopseitig 26 mm, Okularseitig 25,5 mm|
|Lens Coatings||7-lagig Mehrschicht-entspiegelt|
|Prism Coatings||7-lagig Mehrschicht-entspiegelt|
|Included Accessories||ABS hard plastic case, T-2 thread adapter, Zeiss ring dovetail|
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