ASC’s 2″ SCTmirror diagonal is an excellent alternative to higher priced diagonals for those on a budget or just getting started in the 2″ format. This diagonal features Al + SiO2 coatings with 92% reflectivity across the visible spectrum and a 1/10 wave mirror. This ASC diagonal offers excellent mechanical and optical quality at a great price.
You can attach this diagonal directly to Schmidt-Cassegrain telescopes and many Maksutov-Cassegrain telescopes, as long as there is a SCT male thread on the telescope. The standard SCT thread is a 2″x24tpi thread.
A 1.25″-2″ adapter is included so you can use this diagonal with 1.25″ or 2″ eyepieces. The 1.25″ and 2″ holders both feature a brass compression ring, so your eyepiece barrels will not be scratched by the set screw. The 1.25″-2″ adapter is also threaded to accept 2″ filters. The clear aperture is 38.2mm.