Looking for the best Telescope Diagonals?
Discover now our comparison of the best Telescope Diagonals. It is never easy to choose from the wide range of offers. On the market, you will find an incalculable number of models, all at different prices. And as you will discover, the best Telescope Diagonals are not always the ones at the highest prices! Many criteria are used, and they make the richness and relevance of this comparison.
To help you make the best choice among the hundreds of products available, we have decided to offer you a comparison of the Telescope Diagonals in order to find the best quality/price ratio. In this ranking, you will find products listed according to their price, but also their characteristics and the opinions of other customers. Also discover our comparisons by categories. You won’t have to choose your products at random anymore.
No. 1
SVBONY SV188P Dielectric Mirror Star Diagonal, 90 Degree Mirror Diagonal, 99% Reflectivity Dielectric Coatings with Brass Compression Rings (1.25 inch)
- Dielectric coatings; super flat mirror with dielectric coatings to reduce reflected light loss; provide an over 99% reflective surface; good for astronomical viewing
- 1.25 inches nosepiece fits 1.25 inches telescopes; accepts standard 1.25in filters; eyepieces; Barlow lenses and other accessories with a 1.25in insert barrel
- 90 degree viewing angle; diagonal reflects the telescope’s light path 90 degree to provide a more comfortable viewing angle; best for observing objects overhead
- Correct upside down and left right reversed image; the view image is upright; but left and right reversed if use the 90 degrees to your telescope
- Brass compression ring; Built in brass ring and thumbscrew accessories avoid eyepiece to rotate during adjustments; effortless fixes more firmly and will not scratch your eyepieces barrels
$42.99
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No. 2
Astromania 1.25 Inch Telescope Diagonal with Amici Erecting Prism - 90° Fully-Coated Star Diagonal for Upright & Clear Astronomical Viewing, Metal/Plastic Construction, Enhanced Optical Transparency
- 90° Telescope Diagonal for Comfortable Viewing: Experience effortless astronomical observation with Telescope Diagonal Mirror featuring 90° angle design; Maintain an upright & comfortable posture, whether observing planets or terrestrial landscapes
- Erect Image Diagonal with Amici Prism Technology: The integrated Amici Prism Diagonal BK7 optical glass corrects image orientation; delivering upright & non-reversed views—perfect for birdwatching and deep-sky exploration
- Premium Fully-Coated Diagonal for Optimal Clarity: Multi-layer dielectric coatings on prisms and lenses ensure 89% reflection for a bright image; surpassing standard mirrors in brightness and sharpness for Star Diagonal applications
- Resitant 1.25 Inch Telescope Diagonal Build: Combining an premium-grade aluminum barrel and impact-resistant ABS housing, this diagonal withstands extreme temperatures from -20°C to 60°C while fitting all 1.25" focusers
- Enhanced Compatibility & Versatility: Utilize the M28.5×0.6mm filter thread to attach 1.25 inch moon filters or nebula filters, expanding your telescope diagonal’s functionality across celestial and terrestrial targets
- Control Engineering for Crisp Imagery: Internal glare-eliminating threads and dual rubber dust caps minimize glare and debris; ensuring to improve brightness of image and reduce dark edge formed
- Sophisticated Aesthetics & Ergonomics: The high-gloss finish resists fingerprints and scratches, while the compact lightweight design ensures portability for field astronomy
$27.97
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No. 3
SVBONY SV221 90 Degree Diagonal Mirror, Telescope Diagonal 1.25 inches with Brass Compression Rings, Telescope Accessory for Refractor Telescope
- Enhanced Aluminum Die; the SV221 diagonal mirror is designed with enhanced aluminum mold; which has higher light transmittance and clearer vision
- 1.25 inches diameter; the SV221 diagonal mirror has a diameter of 1.25 inches; which can be applied to a 1.25 inches telescope and a 1.25 inches eyepiece
- With a brass pressure ring; the SV221 diagonal mirror has a brass pressure ring; which can prevent surface damage and scratch marks when the eyepiece is used with the SV221
- Supports 1.25-inch filters features internal extinction treatment and supports the connection of 1.25-inch filters; Offering versatility for various observations
- With filter thread; the SV221 diagonal mirror has M28.5x0.6mm filter thread; which supports the connection of 1.25 inches filter
- 90 degrees design; the SV221 diagonal mirror 90 degrees deflection angle design; you don't have to bend over when performing visual observation; and the observation experience is more comfortable
- Internal extinction design; the SV221 diagonal mirror has internal extinction treatment; and the acquired image is clearer and brighter
$19.99
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No. 4
Alstar 1.25 inch 90 Degree Diagonal Mirror - Telescope Diagonal Mirror for Refractor Telescope - Filter Thread for Any 1.25 inch Filter and Accepts Standard 1.25 inch eyepieces
- 90-Degree Viewing Angle: Features 90 degree observing design more comfortable viewing orientation as you observe from above;reducing unnecessary postural strain
- Multiple Lense Optical: Premium lenses are engineered to maximize light transmission; delivering clear vision with enhanced optical clarity
- Quick Installation:Dual installation design with meticulous craftsmanship facilitates safer and more efficient installation of 1.25 inch telescope accessories
- Upright Image and Lateral Inversion: 1.25 inch 90 degree zenith mirror provide stable observation; obtaining vertically erect with lateral inversion
- Double Installation Options: Dual design includes threaded and 1.25 inch barrels for different mounting needs; but not recommended for Reflectors and Newtonians
$18.99
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SaleNo. 5
Celestron 93573 Dielectric Star Diagonal 2" with Twist Lock
- Enjoy better views through your telescope with this premium diagonal featuring diffraction-limited optics and dielectric coatings
- Provides a 90° viewing angle, perfect for more comfortable viewing through refractor and cass grain-type telescopes
- 58 layers of dielectric coatings provide an over 99% reflective surface, ensuring the maximum amount of light collected by the telescope reaches the eyepiece
- Twist-lock keeps the eyepiece centered in the diagonal to provide better optical alignment
- Includes a Stepdown adapter, so the diagonal accepts eyepieces, Barlow lenses, threaded filters, and other accessories in both 2” and 1. 25” sizes
−14%
$223.43
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No. 6
SVBONY 1.25 inches 90 Degree Dielectric Mirror Diagonal Fully Metal for Refracting Telescope Eyepiece Lens for Astronomical Visual Astrophotography
- The 90% reflectivity flat mirror can reduce light loss and make the field of view clearer and sharper
- Standard 1.25 inches diameter can be used with 1.25 inches telescope accessories such as eyepieces and barlow lens
- 90 degree viewing angle; provide a more comfortable observation angle to observe the stars above the head
- Compatible with refractors and catadioptric telescopes; not suitable for reflector telescopes
- Body material is full metal; With dust cover always keep your lens clear prolong life
$31.99
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No. 7
Astromania 1.25" 90-Degree Diagonal Mirror - More Comfortable Viewing Orientation as You Observe from Above, Filter Thread for Any 1.25" Filter and Accepts Standard 1.25" eyepieces
- 1.25 inch 90 degree mirror star diagonal for any telescope with 1.25 inch connector but not suitable for Newtonians
- More comfortable viewing orientation as you observe from above; filter thread for any 1.25 inch filter; accepts standard 1.25 inch eyepieces
- Protective coating on the mirror to ensure a long life; metal barrel for secure seating in the focuser
- Useful for refractor and Cassegrain telescopes but not recommended for reflectors
- Wide 90 degree angle: you can view correct image from refractor telescope stand and just look down with a comfortable angle
$20.97
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No. 8
Astromania 2 Inch Star Diagonal 90-Degree Mirror with 93% Reflectivity Dielectric Coatings - Fully Metal for Refracting Telescope Eyepiece Lens for Astronomical Visual Astrophotography
- The 2 Inch Diagonal Telescope allows you to take advantage of the wider field of view provided by 2 inch telescope eyepiece; enjoy better views through your telescope with this premium diagonal featuring diffraction-limited optics and dielectric coatings
- Clear and Bright Image: The 2 diagonal features dielectric coatings with 93 percent reflectivity across the visible spectrum and a 1/10 wave mirror for bright and true images; dielectric coatings are more durable than regular or enhanced aluminum coatings
- 2 Inch Diameter: It fits all rear cells of Schmidt-Cassegrain telescopes equipped with a big 2 inch focuser and can use with refractor telescopes with not included SCT adapter which you can find in our store
- 90 Degrees Design: Associated with 90 degree mirror diagonals which let you view objects that are at a 90 degree angle from the direction the telescope is pointing; which can provide you with a better observation experience during visual observation
- Excellent Aluminum Materials: It is constructed from aluminum alloy; which significantly enhances the 2 Inch star diagonal longevity; improved attachment design features a brass clamping ring which does not mar and provides a more secure connection
$65.99
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SaleNo. 9
Celestron 93527 2 inch LT Diagonal Mirror for SCT Telescope, Black
- 2” SCT mirror diagonal with high performance XLT coatings
- 1/10th wave mirror is tested with an interferometer to ensure quality
- Housing is precision machined to achieve and hold good optical alignment.
- Includes a 2” to 1.25” adapter and aluminum carry case
−13%
$161.35
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No. 10
Astromania Telescope Diagonal 2 Inch 90-Degree Diagonal Mirror 99% Reflective Dielectric Coating Erect Image with 1.25 Inch Adapter - Provide a Much Brighter Image Than with an Ordinary Star Diagonal
- The 2 inch telescope diagonal features a 99 percent reflective surface; the optics are crafted from Pyrex glass; additionally; equipped with an SCT interface and a 1.25-inch adapter; significantly broadening the range of compatible telescopes and accessories
- Multi Layered Dielectric Coatings: Dielectric coatings on the super-flat mirror reduce reflected light loss; providing a surface with over 99% reflectivity for brighter and harper images; which is highly beneficial for astronomical observations
- Wide Compatibility: Suitable for refractors included Schmidt-Cassegrains; ACF; EdgeHD and Maksutov-Cassegrains; it can be connected to other eyepieces; barlow lens and filters; among other accessories; via a 1.25-inch adapter
- 90 Degrees Design: The Astromania 2 inch 90-Degree 99% Dielectric Diagonal Mirror adopts a 90 degrees design; which can provide you with a better observation experience during visual observation
- Premium Aluminum Material: It is constructed from aluminum alloy; which significantly enhances the star diagonal longevity; equipped with brass compression ring; non-marring compression safety secures the eyepieces
$147.97
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Last update on 2025-06-09 / Affiliate links / Images from Amazon Product Advertising API