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Baader 2" BBHS ® Mirror Diagonal with 2" ClickLock Clamp

Baader 2" BBHS ® Mirror Diagonal with 2" ClickLock Clamp

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Baader 2" BBHS ® Mirror Diagonal with 2" ClickLock Clamp

# 2456115

€ 425.00 Price excl. German VAT tax (19%): € 357.14

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2" BBHS star diagonal with 2" ClickLock terminal and black case. Provides greatest reflectance over most spectral range from 390 to 2000nm
Much higher in brilliance than standard dielectric coatings
BBHS = Broadband Hardsilver coating with dielectric protective overcoating
T-2 BBHS-Sitall zenith mirrors on both sides with T-2 Photo thread

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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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Can I use an UV/IR-Cut filter or the BBHS mirror in front of an H-Alpha or Calcium Solar Filter? Do you recommend the 2" BBHS or 2" Clicklock Mirror for solar observation?

Question by: Enrique V. on Sep 26, 2016 3:04:00 PM | 1 Answer(s)

If you want to observe the sun in H-Alpha, we recommend the standard dielectrical Clicklock mirror (# 2956100) in combination with a suitable filter combination, because the dielectrical filter reflects less radiation below 380nm and above 740nm. This way, the mirror can reduce the strain on the following filters at least a little bit.Please do also use an energy rejection filter in front of the telescope to reduce the strain on the filters as much as possible.

We highly advise against visual calcium observations of the sun - the 397nm of Calcium are already ultraviolet radiation, and UV-radiation can cause phototoxic reactions which can harm your eyes. In addition, even young people can't see these wavelengths very good, and sensitivity decreases with the age. Because of this, the eye doesn't feel if the intensity is much too high. If you now try to increase the amount of radiation (e.g. with another mirror) to achieve a brighter image, you will increase the risk for eye damage. According to the newest norms for eye safety and to ophtalmologist conclusions, the sun must not be observed visualy at 397nm.

We highly advise to only observe the sun in calcium photographically, then you also do not need a star diagonal. We can't understand why some manufacturers promote these calcium-filters for visual observations.

We also advise against placing a filter so close to the focus - any energy rejection filter belongs in front of the front lens, even if this sets high demands to the quality of such a large filter. Placing the filter close to the focus will save money, because you can use a much smaller filter, be we absolutely can't recommend it - because of our own conscience as well as because of EU-regulations. The filter would receive all the energy collected by the front lens. We can only recommend putting the energy rejection in front of the front lens, which is the ethically and technically correct method.

Answer by: Baader Web Team (Admin) on Oct 14, 2016 9:32:00 AM

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Hello, Is your mirror coated on the front of the glass on your Baader 2" BBHS ® Mirror Diagonal with 2" ClickLock Clamp? As in a front surface mirror? Thank you! David

Question by: David on Sep 20, 2018 12:11:00 AM | 1 Answer(s)

Tell me, please, what is the best diagonal to choose for observing objects of distant cosmos and planets:
Baader 2" BBHS ® Mirror Diagonal with 2" ClickLock Clamp
Baader 2" BBHS ® Prism Star Diagonal Prism with 2" ClickLock Clamp
And yet, the mass of them is indicated the same, is there any error here? The prism should be heavier? Thank you for your responses!

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Question by: Evgeniy on Mar 28, 2017 8:13:00 PM | 1 Answer(s)

There was indeed an error in the specs, the mirror weighs 451g and the prisms weighs 513g. Regarding your question which to choose:
Usually prism diagonals are better suited for long focal length refractors and mirror diagonals for short focal length mirror telescopes.
This is because the total reflection with prisms is suboptimal when using short focal lengths due to nonlinear light reduction with high angle side light rays and chromatic prism effects. Also there are shifts in backfocus and it can influence the correction of high quality optics due to the glasspath (the speed of light is lower inside a dense medium like glass in comparison to air).
On the other side mirrors don't have the same maximum reflection values like a prism's lossless physical total reflection. Also a mirror is much more sensitive to transmission reduction when exposed to the air (sensitive silver layer getting weak very soon).
But with the Baader BBHS self protecting silver reflection layer on both diagonals (mirror and prism) the backsides of both principles are well compensated, this means the mirror diagonal will not loose any light due to aging anymore and the general light angle sensitivity of the prism diagonal due to reliance on total reflection alone is compensated by the additional BBHS layer below the total reflection hypotenuse area.
So the decision between diagonal mirror or prism is not as critical as it was until now.
But still a short focal length instrument favours a mirror diagonal.

Answer by: Baader Web Team (Admin) on Mar 29, 2017 10:49:00 AM

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Does the 2" nose-piece accept standard 2" filters such as Lumicon UHC? If not, what adaptor would i need?

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Question by: John on Nov 17, 2016 1:23:00 AM | 1 Answer(s)

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Specifications

Additional Information

Manufacturer	Baader Planetarium
SKU (#)	2456115
Weight (kg)	0.451
Optical Design	Mirror Diagonal
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	BBHS coated, Dielectrically protected
Image Orientation	Erect image, Mirror inverted
Optical tube length	112
Clamping System	ClickLock
Deflection angle	90°
Inner Diameter / Clear Aperture (mm)	47.5

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