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Baader T-2 Maxbright Mirror Diagonal (T-2 part #01A)

SKU MAX-1 (Baader #2456100)
Original price $249.00 - Original price $249.00
Original price
$249.00 - $249.00
Current price $249.00

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  • 1¼ "Maxbright Universal Star Diagonal
  • Sitall mirror material (glass ceramic with zero expansion coefficient), 1/10 lambda surface finish
  • 140 coating layers for a 99% reflectance
  • Scratch-proof, lifetime durable and absolutely flat!

Baader Planetarium has just expanded their innovation in star diagonals. With their ground-breaking introduction several years ago of their all-dielectric 2" Maxbright star diagonal, Baader brought mirror star diagonals into the 21st century. The mid-size, flexibility, and cost of the T-2 Maxbright Mirror Diagonal make this the ultimate diagonal for high power planetary viewing, or in systems where back-focus or space is limited and a full aperture 2" diagonal will not work or is not flexible enough.

The new T-2 Maxbright Mirror Diagonal uses the proprietary Baader Maxbright all-dielectric mirror coatings. This process results in an amazingly high 99% photo-visual reflectivity. The unique Baader coating system has also been specifically optimized to minimize scatter, and does NOT degrade mirror flatness. The zero expansion mirror substrate retains its true 1/10 wave (p-v) flatness over the entire oversized 35mm (1.38") mirror surface! This allows the mirror to be used well in front of the image plane with no image degradation or astigmatism from a warped mirror surface. In addition, the extreme coating hardness makes the Baader Maxbright highly durable (the coatings are harder than the glass itself!). The Maxbright mirror coatings will last lifetimes without losing reflectivity, and may be cleaned with normal care, without fear of scratches.

T-2 System Design: Like its correct-image sibling (the Precision Amici Diagonal), the design of the T-2 Maxbright Mirror Diagonal enables it to be configured to exactly suit your needs. The input and output T-2 threads integrate with the full range of Baader Astro T-2 System components. It can be configured to install in 2" or 1.25" focusers, for use with all 1.25" eyepieces and even many 2" eyepieces! It is also the perfect diagonal for use with the Baader/Zeiss Giant Binoviewer (replaces the normal prism diagonal). Not just a visual accessory, this diagonal also integrates well into digital imaging applications. Please see the T2 Diagonal Configuration page for some suggested configurations.

Like all the Baader Planetarium products, the mechanical quality and finish are superb. The all-machined aluminum housing supports the mirror at the correct location and at a precise 45 degree angle, to maintain the collimation and performance of your optical system. Even the tiniest exposed lips are sharp V-threaded for stray light control.

* PLEASE NOTE: The Baader T-2 Maxbright Mirror Diagonal incorporates standard T-2 threads at the input and output faces, and is provided as a basic component, without any input or output fittings. This permits the diagonal to be used as a compatible component along with the other Baader Planetarium T-2 accessories, like the VIP Modular Barlow, or for digital imaging. This also enables you to configure the diagonal to exactly suit your needs, and to fit 2" or 1¼” eyepieces, and focusers. The effective optical path length of the base T-2 Maxbright Diagonal is 54mm. Please see Eyepiece Adapters, Rings for applicable fittings.


As part of the ASTRO T-2 System, the T-2 Maxbright Mirror Diagonal, Precision Amici Star Diagonal, and T-2 Prism Star Diagonal can be configured in various ways. All three diagonals use the same precision machined housing and input/output T-2 threads. For some typical configurations, refer to the images below. Given the large apertures of these diagonals, it is possible to configure these diagonals for use with 2" eyepieces (see 2" configuration below). Some vignetting may be noticeable on the largest true-field 2" eyepieces, though some users have even used 30mm Naglers with good results.

In addition to visual configurations, the T-2 Maxbright Mirror Diagonal is well suited for digital imaging. The mechanical and optical quality allow you to position cameras at right angles to the optical path, without any loss in image quality or mechanical rigidity.

Of course, you are free to invent your own application, using any of the T-2 System components. For detailed dimensional specs on all Astro T-2 components, see the ASTRO T-2 System Specs.

T-2 Diagonals, standard configuration for 2" focusers and 1.25" Eyepieces (back focus used in this configuration is 85mm).

  1. Nosepiece 2"/T-2 (T-2 part 16)
  2. Click-Lock Eyepiece Clamp 1¼” /T-2 (T-2 part 08)

T-2 Diagonals, configured for SCT with Quick Changer System

  1. Short T-Adapter (C8,16mm) (# T2-21)
  2. T-2 Quick Change System (# T2-6,7)
  3. Click-Lock Eyepiece Clamp 1¼” /T-2 (# T2-08)

T-2 Diagonals, with VIP Modular Barlow (and 2" nosepiece)

  1. Nosepiece 2"/T-2 (# T2-16) -or- Nosepiece 1¼”/T-2 (# T2-14)
  2. VIP Modular Barlow (# VIPB)

T-2 Diagonals, Configured for 2" eyepieces and focusers

  1. Nosepiece 2"/T-2 (# T2-16)
  2. Deluxe Eyepiece Clamp 2” (# T2-17) - OR - 2" Clicklock Eyepiece Clamp (CLSC-2)
  3. Expanding Ring T-2i/2"e (#T2-28a)

MANUFACTURER Baader Planetarium
SKU (#) 2456100
OPTICAL DESIGN Mirror Diagonal
INNER CONNECTION (LENS SIDED) Thread, T-2 (M42 x 0,75)
REFLECTION SURFACE Dielectrically coated
IMAGE ORIENTATION Erect image, Mirror inverted



Testreview - Mirror vs. dielectric vs. prism diagonal comparison - W. Paolini

Baader Star Diagonals (T-2 and 2")

Learn more about Astro T-2 System

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