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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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6 Review(s) | Add Your Review

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

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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 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)

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 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)

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!!

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Question by: Blue Ridge on Aug 15, 2020 9:51:00 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?

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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?

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

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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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Overview and Recommended Use: Baader Star Diagonals

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Baader BBHS ® reflective properties

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Specifications

Additional Information

Manufacturer	Baader Planetarium
SKU (#)	2456120
Net weight (kg)	0.66
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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