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Diagonals & Accessories

19 Items

Baader T2 BBHS Sitall Mirror Diagonal - MAX1S

SKU: BAD-MAX1S
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: T-2 Threads
  • Diagonal Size - Telescope Side: T-2 Threads
  • Optics Type and/or Coatings: BBHS Coatings , Sitall Optics
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$299.00
Baader Planetarium 2" ClickLock Mirror Diagonal

Baader MaxBright 2" Clicklock Mirror Diagonal - CLDIAG-2

SKU: BAD-CLDIAG-2
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel
  • Includes Eyepiece Adapter: No, 1.25" Eyepiece Adapter Sold Separately
  • Optics Type and/or Coatings: Maxbright Coatings
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$309.00
Baader 2" BBHS Mirror Diagonal

Baader 2” BBHS Sitall Mirror Diagonal - MAX-2S

SKU: BAD-MAX-2S
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel
  • Includes Eyepiece Adapter: No, 1.25" Eyepiece Adapter Sold Separately
  • Optics Type and/or Coatings: BBHS Coatings , Sitall Optics
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$499.00
Baader Planetarium SCT Lock Ring for 2" Maxbright Diagonal

Baader Planetarium SCT Lockring for 2" Maxbright Diagonal - LRING

SKU: BAD-LRING
  • Using this Lock Ring increases the flexibility of placement for the Baader Maxbright Diagonal.

  • One side of the Lock Ring is compatible with SCt threads.

  • Turning Baader's Lock Ring counter-clockwise will lock the diagonal into place.

  • Before locking, the diagonal can be turned to reach the desired angular position.
$44.00
Baader Planetarium 1.25" T-2 Maxbright Mirror Diagonal

Baader Planetarium T-2 Maxbright 1.25" Mirror Diagonal - MAX-1

SKU: BAD-MAX-1
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Maxbright Coatings
$249.00
Baader 1.25" Amici Correct Image Star Diagonal

Baader 1.25" Amici Correct Image Star Diagonal - AMICI-DX1

SKU: BAD-AMICI-DX1
  • Diagonal Type: Correct/Erect Image
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: 7-Layer Multi-Coating , Amici Prism
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$319.00
Baader Planetarium Flip Mirror II Star Diagonal
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$227.00

Baader Planetarium 2" to 1.25" Reducer with T2 Threads - T2-15

SKU: BAD-T2-15
  • This Baader Planetarium reducer is compatible with all 2" Focusers.

  • Using this reducer allows users to use 1.25" eyepieces and accessories in a 2" focuser.

  • The reducer has a 3-point attachment system and is vibration free.

  • Baader has designed this reducer with 48 mm filter threads and an internal T-2 thread.
$49.00
Baader Planetarium T2 90º Prism Star Diagonal with 1.25" Nosepiece and 1.25" Eyepiece Holder

Baader T-2 90º Prism Star Diagonal with 1.25" Nosepiece & Eyepiece Holder - PRISM-1

SKU: BAD-PRISM-1
  • Diagonal Type: Prism Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: 7-Layer Multi-Coating
$169.00
Baader 2" Zeiss Prism Star Diagonal with BBHS Coatings & 2" ClickLock Eyepiece Holder

Baader Planetarium 2" Prism Star Diagonal with BBHS Coatings & 2" ClickLock Eyepiece Clamp - PRISM-2Z

SKU: BAD-PRISM-2Z
  • Diagonal Type: Prism Diagonal
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel
  • Includes Eyepiece Adapter: No, 1.25" Eyepiece Adapter Sold Separately
  • Optics Type and/or Coatings: BBHS Coatings, Prism held to strict Zeiss specification
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$539.00
Baader Planetarium T2 90º Star Diagonal Zeiss Prism

Baader T2 90º Star Diagonal Housing - Zeiss Prism, 34mm Clear Aperture - T2-01B

SKU: BAD-T2-01B
  • Diagonal Type: Prism Diagonal
  • Diagonal Size - Eyepiece Side: T-2 Threads
  • Diagonal Size - Telescope Side: T-2 Threads
  • Optics Type and/or Coatings: 7-Layer Multi-Coating , Zeiss Optics
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$272.00
Baader Planetarium T2 90º Prism Diagonal Housing - 32 mm Clear Aperture

Baader T2 90º Prism Diagonal Housing - 32mm Clear Aperture - T2-01C

SKU: BAD-T2-01C
  • Diagonal Type: Prism Diagonal
  • Diagonal Size - Eyepiece Side: T-2 Threads
  • Diagonal Size - Telescope Side: T-2 Threads
  • Optics Type and/or Coatings: 7-Layer Multi-Coating
$129.00

Baader 2" 90-Degree Erecting Amici Prism Diagonal with 1.25" Adapter

SKU: BAD-AMICI-2
  • Diagonal Type: Correct/Erect Image
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel
  • Includes Eyepiece Adapter: Yes, 2" to 1.25"
  • Optics Type and/or Coatings: 7-Layer Multi-Coating , Amici Prism
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$299.00
Baader Clicklock 2" to 1.25" Reducer Adapter

Baader Clicklock 2" to 1.25" Reducer - T2-15B

SKU: BAD-T2-15B
  • The Clicklock reducer from Baader holds 1.25” eyepieces.

  • A 20-degree twist of the knurled outer ring will lock and unlock the eyepieces in place.

  • A Clamp Lever is included to indicate clamp position.

  • The reducer is made from hardened bronze.
$89.00

Baader 1.25" Amici 45º Erecting Prism w/24 mm Clear Aperture - AMICI-45

SKU: BAD-AMICI-45
  • Diagonal Type: Correct/Erect Image
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Amici Prism
$92.00
Baader Planetarium 2" Amici 45º Erect Prism with 2" SCT Thread & 2" to 1.25" Reducer

Baader 2" Amici 45º Erecting Prism w/2" SCT Thread - AMICI-45-2

SKU: BAD-AMICI-45-2
  • Diagonal Type: Correct/Erect Image
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: SCT Threads
  • Includes Eyepiece Adapter: Yes, 2" to 1.25"
  • Optics Type and/or Coatings: Amici Prism
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$239.00
Baader Planetarium 2" 90º Astro Amici Diagonal Prism with BBHS Coating

Baader 2" Astro Amici 90º Diagonal Prism with BBHS® Coating - AMICI-DX2

SKU: BAD-AMICI-DX2
  • Diagonal Type: Correct/Erect Image
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel
  • Includes Eyepiece Adapter: No, 1.25" Eyepiece Adapter Sold Separately
  • Optics Type and/or Coatings: Amici Prism , BBHS Coatings
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$719.00
Baader 1.25" 45º Maxbright Amici Erecting Prism

Baader 1.25" Maxbright Amici 45º Erecting Prism with Integrated 2X Glass Path Corrector - MAXAMICI

SKU: BAD-MAXAMICI
  • Diagonal Type: Correct/Erect Image
  • Diagonal Size - Eyepiece Side: T-2 Threads
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Amici Prism , Maxbright Coatings
$115.00 $92.00
Baader Planetarium 2" to 1.25" Pushfix T2 Thread Reducer

Baader Planetarium 2" to 1.25" Pushfix T-2 Thread Reducer - T2-15A

SKU: BAD-T2-15A
  • This thread reducer only has 1 mm optical path length.

  • The Pushfix reducer has three methods of attaching 1.25" accessories.

  • Baader has designed this reducer to work best with Newtonian Focusers.

  • With Countersunk Delrin grub screws, this reducer enables correct pressure.
$43.00

A star diagonal is a useful astronomy accessory because it allows viewers to look through their telescope perpendicular to the direction the telescope points or at a 45° angle. This makes diagonals handy for terrestrial observations as well. The people at High Point Scientific understand that the comfort and convenience of using a star diagonal is important to you, that is why we offer many different types of telescope diagonals for you to choose from. You will find the latest brands offering a variety of diagonals, including mirror, dielectric, and prism diagonals.


As the name suggests, mirror diagonals use a mirror to turn the telescope’s image at a 90° or 45° angle. This creates an image that is correctly oriented vertically but reversed horizontally. The mirror is typically made of silver or aluminum, both of which scratch easily. You will need to careful when cleaning and using your mirror diagonal. However, mirror diagonals are often very affordable which makes them a favorite among amateur astronomers.


Many astronomers prefer mirror diagonals but wish they were more durable. That’s why High Point Scientific also offers dielectric diagonals. Dielectric diagonals are mirror diagonals but include enhanced dielectric coatings for greater durability and reflectivity. These coatings make dielectric diagonals hard and sturdy so it is much more difficult to scratch or mar mirror surfaces.


Prism diagonals are often considered the most innovative design for a diagonal. They use a glass prism that often produces higher reflectivity than mirror or dielectric diagonals. This means that prism diagonals suffer minimal light loss to give you high contrast celestial views. Be sure to look for Amici prism diagonals on the High Point Scientific website, as these produce an upright image with a correct left-right view for low-powered eyepieces.

High Point Scientific is rated 4.9/5 based on 1347 reviews