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Baader 2"/90° Astro Amici-Prism with BBHS ® coating

Baader 2"/90° Astro Amici-Prism with BBHS ® coating

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# 2456120

€ 595.00 Price excl. German VAT tax (19%): € 500.00

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Manual and Recommended Use: Baader Star Diagonals(T-2 and 2")

2" ClickLock-Clamp and 2" nosepiece.
Suited for astronomical observation at high magnification
Hard-silver-coated and protected against aging. Astro quality, manufactured by Zeiss standard

Product Questions

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)

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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What advantage does the amici have over the roof prism? Which is better for astronomy? which is better for terrestial?

Question by: Allan Smith on Mar 25, 2017 8:38:00 PM | 1 Answer(s)

Is a roof line spike visible using the 2" Baader Amici prism in the telescope at low or high power? I plan to use the prism for astrophotography and really need the short back focus that this diagonal provides.

Question by: Joel Cohen on Sep 12, 2019 11:20:00 PM | 1 Answer(s)

Should I unscrew the 2" nosepiece of this eyepiece by hand? If so, it should be clockwise or conter clockwise?

Question by: Rafael Sampaio on Jul 2, 2020 8:05:00 PM | 1 Answer(s)

I have treated myself to this Baader Amici Prism!! However - I am now concerned with reading reports from online astronomy forums regarding this prism sometimes causing a 'roofline diffraction spike' in the eyepiece image. Will this happen to me?? I will only use the prism for visual astronomy, not photography. Focal Ratio of my telescope = F10, focal length = 2800 mm. Celestron CPC1100. Most of my viewing will be in the 100X to 250X magnification range. Thanks for any reassurance you can give me! PS I love your products!!

Question by: Blue Ridge on Aug 15, 2020 9:51:00 PM | 1 Answer(s)

Is it possible to have the same quality (suitable for hight magnifications) with an erecting capacity ?

Question by: Jean-Noël FERRIER on Sep 29, 2017 9:28:17 PM | 1 Answer(s)

I want to be sure that the Baader 2"/90° Astro Amici-Prism with BBHS ® coating is compatible with all the eyepieces : I have a set of televue ethos and I want to check that the ethos will not bottom the prism inside.

Question by: J-François on Aug 19, 2020 12:56:00 PM | 1 Answer(s)

Baader 2"/90° Astro Amici-Prism with BBHS ® coating + Baader 2" NexStar locking ring is compatibe with OTA Nextar Evolution 9.25?

Question by: Jordi Puig on Feb 24, 2021 7:01:00 PM | 1 Answer(s)

I have the 2456120 diagonal, and it's fine. However the Clicklock-SC clamp I use to fix the diagonal to my C9.25 SCT is too thick. What I really want is something with an SC-thread for the scope and on the other end, something to fit directly into the prism housing. Is there such a thing?

-5

Question by: Bryan Dawson on Jul 15, 2018 10:37:00 PM | 1 Answer(s)

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Spikes with Astro-Amici Prisms

Ich sehe an hellen Objekten Spikes – ist mein Prisma defekt? Concerning Amici prisms, there are two factors which can limit the use for astronomy. The first one is the optical quality, i.e. how good is the alignment of the optical surfaces. Most Amicis are made for terrestrial use, where our atmosphere limits the useable magnification to ca. 60x or 70x, anyway. So, it's fine if they don't show a double image up to ca. 100x, as such high magnifications can't be used. Those prisms which are designed for astronomical use are designed for those magnifications which we can use for the night sky – ca. 300x or even more. This high precision makes our Astro-Amici star diagonals so expensive. But all Amici-prisms – no matter how good they are – suffer from one design feature: There is a line going through the center of the image, where both sides of the prism surfaces com together. This may cause reflections or spikes. To some extent, this will always happen when a bright object like a star is viewed in front of a dark background like the night sky. This should be obvious only with very bright stars or planets, while...
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Optical tube lengths of 2" Clicklock and BBHS mirror diagonals

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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 (#)	2456120
Optical Design	Erecting Prism
Inner Connection (lens sided)	Thread, M48, M55, 2" (50,8mm)
Outer Connection (lens sided)	Barrel, Dovetail ring, S58, 2" (50,8mm)
Inner Connection (eyepiece/-camera-sided)	Thread, Clamp, M55, 2" (50,8mm)
Reflection surface	Sealed BBHS coating
Prism Glass (Type)	BaK-4
AR-Coating	Phantom Coating® Group
Image Orientation	Erect image, Non-reversed
Optical length (mm)	85
Clamping System	ClickLock
Deflection angle	90°
Inner Diameter / Clear Aperture (mm)	44

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