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Diagonals & Accessories

Items 1 - 25 of 28
Apertura 2" Click Lock Carbon Dielectric Diagonal No adapter

Apertura 2" Twist Lock Carbon Dielectric Mirror Diagonal - D2CF

SKU: APT-D2CF
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$129.95
 
Apertura 1.25" Carbon Dielectric Diagonal Full View

Apertura 1.25" Carbon Dielectric Mirror Diagonal - D1CF

SKU: APT-D1CF
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Includes Eyepiece Adapter: No, 1.25" Eyepiece Adapter Sold Separately
  • Optics Type and/or Coatings: Dielectric Coatings
$79.95
 

Apertura 2" SCT Twist Lock Carbon Dielectric Mirror Diagonal - D2QCFSCT

SKU: APT-D2QCFSCT
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$139.95
 
Apertura 2" Quartz Dielectric Diagonal

Apertura 2" Quartz Dielectric Diagonal - A-D2Q

SKU: APT-A-D2Q
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings , Quartz Optics
$129.95
 
Apertura 2" Dielectric Star Diagonal

Apertura 2" Dielectric Star Diagonal - A-D2

SKU: APT-A-D2
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$109.95
 

Meade 2" Diagonal with SCT Adapter - 07680

SKU: MEA-07680
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 2" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel with SCT Adapter
  • Includes Eyepiece Adapter: Yes, 2" to 1.25"
  • Optics Type and/or Coatings: Dielectric Coatings
$149.99
 

High Point SCT Dielectric Diagonal - 2" - HPS-D2SCT

SKU: HPS-D2SCT
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$114.95
 

High Point 2" SCT Quartz Dielectric Diagonal - D2QSCT

SKU: HPS-D2QSCT
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings , Quartz Optics
$139.95
 

High Point 2" Quartz Dielectric Diagonal - HPS-D2Q

SKU: HPS-D2Q
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings , Quartz Optics
$129.95
 

High Point 2" Dielectric Mirror Diagonal - HPS-D2

SKU: HPS-D2
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$109.95
 
High Point 1.25" Dielectric Mirror Diagonal

High Point 1.25" Dielectric Mirror Diagonal - HPS-D1

SKU: HPS-D1
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$69.95
 
Celestron 1.25" Dielectric Star Diagonal with Twist-Lock

Celestron 1.25" Dielectric Star Diagonal with Twist-Lock - 93571

SKU: CEL-93571
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$119.95 $114.95
 
Explore Scientific 2" Dielectric Diagonal

Explore Scientific 2" Dielectric Diagonal - DD02-00CF

SKU: EXS-DD02-00CF
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
Free shipping Free shipping
$169.99
 

Orion 2" Dielectric Mirror Star Diagonal - 08727

SKU: ORI-08727
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$129.99
 

Orion 1.25" Dielectric Mirror Star Diagonal - 08880

SKU: ORI-08880
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$99.99
 
Stellarvue 1.25" Enhanced Dielectric Diagonal

Stellarvue 1.25" Enhanced Dielectric Diagonal - D1030

SKU: STV-D1030
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$99.00
 
William Optics 1.25" Dielectric Diagonal with Carbon Fiber Side Plates

William Optics 1.25" Dielectric Diagonal W/ Carbon Fiber Plates - D-125D-C-DB

SKU: WYO-D-125D-C-DB
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$95.00
 

William Optics Dura Bright 2" Carbon Dielectric Diagonal - D-DIG2D-C-DB-T

SKU: WYO-D-DIG2D-C-DB-T
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$139.00
 
Explore Scientific 3" CF Dielectric Diagonal

Explore Scientific 3" Carbon Fiber Dielectric Diagonal - DD03-01CF

SKU: EXS-DD03-01CF
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 3" Barrel
  • Diagonal Size - Telescope Side: 2" Barrel
  • Includes Eyepiece Adapter: 3" to 2" Adapter Included, 1.25" Adapter Sold Separately
  • Optics Type and/or Coatings: Dielectric Coatings
Free shipping Free shipping
$489.99
 
Orion Twist-Tight Dielectric Mirror Diagonal - 1.25"

Orion 1.25" Twist-Tight Dielectric Mirror Star Diagonal - 40901

SKU: ORI-40901
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$119.99
 
Orion Twist-Tight Dielectric Mirror Diagonal - 2"

Orion 2" Twist-Tight Dielectric Mirror Star Diagonal - 40902

SKU: ORI-40902
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
Free shipping Free shipping
$159.99
 
iOptron 1.25" Dielectric Mirror Star Diagonal

iOptron 1.25" Dielectric Mirror Star Diagonal - 6231

SKU: IOP-6231
  • Diagonal Type: Mirror Diagonal
  • Diagonal Size - Eyepiece Side: 1.25" Barrel
  • Diagonal Size - Telescope Side: 1.25" Barrel
  • Optics Type and/or Coatings: Dielectric Coatings
$79.00
 
iOptron 2" Dielectric Star Diagonal

iOptron 2" Dielectric Star Diagonal - 6232

SKU: IOP-6232
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
$110.00
 
Stellarvue 2" Dielectric Star Diagonal

Stellarvue 2" Dielectric Carbon Fiber Star Diagonal - D1028CF

SKU: STV-D1028CF
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
Available Used from $150.00
$189.00
 
Explore Scientific 2" Dielectric Diagonal

Explore Scientific 2" Dielectric Diagonal - DD02-00CF - Silver Grade Refurb

SKU: EXS-DD02-00CF-SG
  • Diagonal Type: Mirror Diagonal
  • 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: Dielectric Coatings
Free shipping Free shipping
$139.99 $104.99
 

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.

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