Current Price: $31.00
Buy It Now Price: $31.00
Bids: 0

GSO 1.25" 90-deg Mirror Star Diagonal for Refractor Telescope # GSST

GSO 1.25" 90-deg Mirror Star Diagonal for Refractor Telescope # GSST

Ordering Info
USA Shipping
International Orders
Our eBay Store


  • Economical 1.25” 90-deg star diagonal for refractor or catadioptric scopes
  • Aluminized 1/10-wave mirror with SiO2 coating at 92% reflectivity
  • Threaded for standard 1.25” filters

New version: Now with brass compression ring!

GSO's 90-deg mirror diagonal is a very good, economical replacement for the generic diagonal that probably came with your otherwise fine scope. Features Al+SiO2 coatings with 92% reflectivity across the visible spectrum and a 1/10 wave mirror.

The clear aperture is 27.9mm. The main mirror housing is made of precision molded ABS plastic and the two end barrels are precision machined from aluminum. The 1.25" nosepiece is threaded to accept standard 1.25" astronomy filters. Weight: 4.4oz; 2 end caps included. Made in Taiwan.

Please Note: This diagonal can only be used with refractor telescopes and some catadioptric telescopes like Schmidt-Cassegrain, Maksutov-Cassegrain, etc. It not meant for use with Newtonian / Dobsonian reflector telescopes or other variants of Newtonian telescopes.

Note: Occasionally, the product you receive might have a slightly different cosmetic appearance or labeling than what is shown. This can often change from batch to batch according to the whims of the manufacturer. However, you will always receive a brand new, original product as described above.

Back to Top

Filed under: Eyepieces & Accessories