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Baader T-2 Stardiagonal (Zeiss) Prism with BBHS ® coating (T-2 part #01B)

Baader T-2 Stardiagonal (Zeiss) Prism with BBHS ® coating (T-2 part #01B)

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Baader T-2 Stardiagonal (Zeiss) Prism with BBHS ® coating (T-2 part #01B)

# 2456095

€ 243.00 Price excl. German VAT tax (19%): € 204.20

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Baader Star Diagonals (T-2 and 2")

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T-2/90 ° diagonal prism (BaK4 glass) with 35mm free aperture terminal objective side: 2 "or 1¼"
Connection eyepiece: 1¼ "
Prism made in accordance to Zeiss-norms, multi-coated, solid metal case, both sides T-2 connection threads, resulting in extremely short design and adaptable to each telescope system.
Not just the housing is significantly better and the prism is greater, also the planarity and the conformality of the prism faces are about 5x better than standard prisms in plastic housings.

Product Questions and Answers

Do you have a question about this product? Then we would like to ask you to first look through the existing questions and answers, most likely your question has already been answered and you will get the desired information much faster this way. Your question is not listed? Then please click on the button "Ask a question".

Is this the smallest of its kind of 2 diagonals?

Question by: Alexandr Martynov on Dec 1, 2021 3:26:00 PM | 1 Answer(s)

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Are the BBHS coatings easy to clean? Do the coatings have a life comparable to your dielectric coatings? Do the coatings degrade over time and at what rate? Is there a difference in performance between your dielectric diagonal and the BBHS one, what are the differences and are they significant or very slight? I own an early Televue APO 4 inch refractor.

Question by: John on Sep 9, 2016 1:29:00 AM | 1 Answer(s)

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BBHS-mirror coatings require the same care during cleaning as you would give to the protected aluminum-coatings of a Newtonian telescope. Only dielectric coatings have the ultimate hardness to withstand any kind of mistreatment during a cleaning procedure - very similar to our Phantom-Group hard antireflection coatings applied onto our lens surfaces.

Any reflecting telescope with classic coatings can attain a lifetime of 20 or 30 years - correct handling provided. The same accounts for our protected silver-coatings, whereas the position of a stardiagonal within the optical train does provide much better protection against environmental influences, compared to the exposed surface of a primary telescope mirror.

We do regard the benefit of the BBHS hardsilver coating to be quite noticeable, compared to the reduced spectral range offered by a dielectric coating. Please check in the Internet for statements that would verify our position. Or look for the very extensive tests on star diagonals, performed by William Paolini (see tab "Downloads".

Please read more on the properties of our star diagonals and our design philosophy here: http://www.baader-planetarium.com/en/blog/baader-bbhs-reflective-properties/

Answer by: Baader Web Team (Admin) on Sep 15, 2016 8:22:00 AM

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-25

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Does it make sense to use a T2-2" clicklock on this for a 2" eyepiece? Or it's better to just use 1.25" clickclock and eyepiece given the connection interface size is only T2.

Question by: Howard on Nov 3, 2017 4:14:00 AM | 1 Answer(s)

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Hello! Can I photograph through this 2" diagonal if I have an APS-C matrix?

Question by: Alexandr on Nov 27, 2021 4:50:00 PM | 1 Answer(s)

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I have a Baader 2" Clickclock diagonal mirror. Can I remove the 2" Clicklock from that diagonal and attach it to the T-2 Ziess prism diagonal?

Question by: Matt on Oct 3, 2019 6:56:00 PM | 1 Answer(s)

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Is it possible to unscrew/remove the male T-2 thread on the prism diagonal, thereby exposing a female thread? I would dearly love a T-2 prism diagonal with female threads on both ends...

Question by: Mort on Nov 18, 2021 6:31:00 PM | 1 Answer(s)

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After a few years of using the Zeiss T2 diagonal, I am fully satisfied with its modularity and the result on TV-85mm.
I was wondering what is the light transmission rate (99% reflectance for T-2 Maxbright Mirror) nothing indicated for the T-2 Stardiagonal (Zeiss)?

Question by: yann on Nov 7, 2021 6:01:00 PM | 1 Answer(s)

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-6

I have an application where I need the male and female threads swapped. Will it work if I turn the prism diagonal around and send light through in the opposite direction? (The light would be entering the end of the prism diagonal that has the male T2 thread.)

Question by: Mort on Nov 17, 2021 9:12:00 PM | 1 Answer(s)

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-6

Dear Baader for my dobson 18' f4 do you suggest to use the T2 zeiss prism diagonal or the T2 mirror? I mostly observe planets hires more then deep sky objects. I was thinking to prism due to future binoviewer but I heard prism could be an issue on a fast f4 scope for bad correction

Question by: Jack on Sep 4, 2018 11:00:00 AM | 1 Answer(s)

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-9

I would like to know if the Baader Planetarium Prism T2 Diagonal 32mm MaxBright (#2456005) and also the Baader Planetarium StarDiagonal Prism T2/90 ( #2456095 ) have the BBHS silver coating on the prism ? I have ask about this here in the states but no one seems to know the answer.

Question by: Max Harrell on Jan 25, 2017 11:13:00 PM | 1 Answer(s)

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-16

The 32mm star diagonal (#2456005) is produced in the regular way - just like prisms are being made since four hundred years - without ANY coating applied onto the hypothenuse (reflecting) face. Please also check our website, nowhere do we state that this star diagonal would feature our BBHS-coating.

Any beam of light that will hit that uncoated surface under exactly 45° of incoming angle will undergo a "total reflection" (as soon as there would be a regular antireflection coating applied onto that reflective face, the performance would suffer greately). For ages Carl Zeiss had preferred the total reflection of prisms versus the reflective surfaces of mirrors, because until recently mirrors did tend to age (produce haze) very quickly.

For the BBHS T-2 prisms we needed perfect reflection also for very short focus telescopes and we wanted to produce a prism that could be used for a wide range of purposes - also for other reflective angles than exactly 45°. In this sense the BBHS-coating applied onto the T-2 prisms offers "another league" of functionality - and the hard silver coating will keep this optical surface to stay clean for ages, whereas the open glass surface of the 32 mm prism will be prone to collect some dust or even dew over time.

Still the 32mm prism is mounted within a precision metal housing, suitable to carry the weight of the Maxbright and heavier binocular viewers asf. It offers the very shortest light path for attaching - say - a Maxbright Bino onto any telescope due to its T-threads. In this way we regard it as a very good solution for any low-cost binocular viewer, since the optical polish of the prism faces is made very precise, with the extended optical distance in mind that adds itself into the light path when putting the added mechanical length of a binoviewer between the 90° prism and the eyepiece focal plane. Regular 90° prisms often feature a plastic housing and are only made to supply sufficient optical quality for an eyepiece to be mounted directly atop such a prism face.

Conclusion: each of these two prisms (32mm as well as BBHS T-2) are top performers within their respective price range. And if you plan to ever use a Mark V Binoviewer, the T-2 BBHS prism will be the first and most useful investment for an undeteriorated viewing experience.

Read also more on Baader BBHS Reflective Properties:
http://www.baader-planetarium.com/en/blog/baader-bbhs-reflective-properties/

Answer by: Baader Web Team (Admin) on Jan 26, 2017 11:01:00 AM

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Overview and Recommended Use: Baader Star Diagonals

The most versatile tools: Baader Star Diagonals (T-2 and 2") Manual and Recommended Use A Baader star diagonal (both prisms and mirrors) can show you impressive images for a lifetime and offers more connection and configuration options than standard star diagonals. Baader Planetarium's star diagonals not only offer the highest mechanical and optical quality, but also have the additional advantage of being part of a large, modular system. They enable very short adaptations as well as threads for direct connections to a telescope or a Baader focuser, as well as adaptation to a wide range of threads for torsion-free use with heavy or long accessories, such as binoviewers. Decades of customer feedback led Baader Planetarium to create a seemingly overwhelming amount of adapters. But each adapter has its purpose. This is the reason why you can always find the optical length of each part in the product description, so that you can find the best solution for your needs. To get the most out of them, we recommend that you spend a few minutes reading this brochure. On the following pages you will find a guide on how to choose coating and star diagonal type an overview of the different...
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Baader BBHS ® reflective properties

Exclusively available on Baader Sitall Ceramic Mirrors and on selected Baader prism Star Diagonals: BBHS® reflection coatings predominantly are being utilised on our highest quality grade 2" BBHS® Sitall Stardiagonals (#2456115 – incl. black housing and 2" ClickLock clamp) as well as on the BBHS® T-2 Sitall Stardiagonal (#2456103) - where the housing features a male and female T-2 thread - for shortening the optical path with bino use, and to offer the utmost in adaptation variability as well as much more light throughput than with any conventional 1 1/4" star diagonal. BBHS® stands for Broad Band Hard Silver. When applied onto our Sitall (zero expansion glass-ceramics) substrates, these multiple deposited layers of hard silver are being sealed by a set of dielectric layers to achieve long term durability. With this advance in coating technology our BBHS® coating lifetime equals that of a high quality AlSiO2 coating, matching the durability of standard aluminium coated diagonals (and telescope mirrors) which have been in wide use for many years. The BBHS® spectral bandpass is much wider though, when comparing with our 50 layer all dielectric coatings utilized on the 2" ClickLock Star Diagonals. The all dielectric coating system on the 2" ClickLocks...
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Specifications

Additional Information

Manufacturer	Baader Planetarium
SKU (#)	2456095
EAN Code	4047825011299
Net weight (kg)	0.17
Optical Design	Star Diagonal Prism
Inner Connection (lens sided)	Thread, T-2 (M42 x 0,75)
Inner Connection (eyepiece/-camera-sided)	Thread, M34
Outer Connection (eyepiece/-camera-sided)	Thread, T-2 (M42 x 0,75)
Reflection surface	Sealed BBHS coating
Glas path	36 mm
AR-Coating	Phantom Coating® Group
Image Orientation	Erect image, Mirror inverted
Optical length (mm)	38,5
Clamping System	no clamp
Deflection angle	90°
Inner Diameter / Clear Aperture (mm)	34

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