1.25" SV188P Dielectric Diagonal for Refractor

SKU: F9171B
US$ 42.99
  • 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
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3 reviews

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Great piece!

Perfect product with excellent features. And sustainable package, without needless papers and prospects and plastic. But please tell your customers, which adapter is needed for Cassegrain - and give the link to the product in your shop!

Bright and contrasty

I bought the 1.25 "mirror to be able to look into the zenith on my previous telescope. In contrast to a simple zenith mirror, the Svbony SV188P Dielectric Diagonal is a real win. The image is visibly brighter and the image quality at high magnification has also improved. Thanks to the ring clamp, the eyepieces remain free from scratches. Overall a very good mirror!

Diagonal dieléctrica

Buenas me gustaría saber cuál es el adaptador especial para la.diagonal dieléctrica sv188 P . Gracias.
Model Number SV188P
Size 1.25-Inch
Coatings Dielectric
Reflectivity dielectric 99% coating for bright images
Material Aluminum Alloy
Filter Threads M28.5*0.6
M4 Set Screws Yes
Net Weight 125g / 4.41oz


There are many 1.25" star diagonals on the market. Many of them have a mediocre mirror quality with 90% reflectivity (10% loss) and a plastic body.  The 1.25" diagonal by SVBONY stands for a high-quality alternative to those cheap parts. It offers excellent image and mechanical quality. There's no vignetting over the full 1.25" field. SV188P features sophisticated, Multi-layered dielectric coatings that provide an astounding 99% reflectivity for maximum view brightness and sharpness.

SV188P Diagonals provides a comfortable 90-degree viewing orientation when observing the night sky through a refractor. When use the SV188P with Maksutov-Cassegrain (Mak-Cass) or Schmidt-Cassegrain telescope, you need a special adapter. 

Another advantage is the 1.25" nosepiece barrel is threaded to accept 1.25-Inch filters. Brass lock Screw and Brass Compression Rings feature more precision and prevent barrels or the surface of eyepieces from marring and scratching.


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