The SCT rear cell attachment ring will thread directly onto Celestron SCT rear cells and onto the rear cells of those Meade SCTs that do not have the electric microfocuser as standard equipment, These include older 2080 and 2120 scopes; all LX3, LX5, LX6, and Premier scopes; all current and past LX90s; and all earlier LX200 scopes that were supplied without microfocuser. The diagonal will thread onto a microfocuser-equipped scope if you install the SCT rear cell ring that came with the focuser into the microfocuser’s 2” drawtube. If you want a diagonal with a 2” barrel that will slip directly into the microfocuser’s 2” drawtube, consider the Astro-Tech 2” refractor diagonal instead.

The diagonal uses a finely-polished 10mm thick 1/10th wave BK7 optical glass substrate for stability in changing thermal conditions. The mirror housing is precision-machined from solid aluminum, rather than simply a flimsy plastic box or a sheet metal stamping, as you’ll find with ordinary diagonals. A rigid U-shaped die-cast metal backplate with stainless steel hardware holds the mirror in perfect optical alignment in the machined body. The solidity of the construction is mirrored in the diagonal’s substantial 17 ounce weight.

The interior of the body is lined with light absorbing materials, in addition to being anodized an antireflective matte black. The short nosepiece that holds the rear cell attachment ring is internally antireflection threaded for high contrast. The attachment ring fits both Celestron and Meade rear cells. It is knurled for a sure grip so it can be easily loosened, even when wearing gloves, allowing you to rotate the diagonal to the most comfortable observing position.

Rather than using a metal thumbscrew that contacts eyepiece barrels directly and can scratch them, the diagonal’s 2” eyepiece holder uses a non-marring soft brass compression ring to firmly hold 2” eyepieces and the standard equipment 1.25” eyepiece adapter. The knurled chrome thumbscrew that operates the compression ring is a full 1/2” in diameter, twice that of competitive diagonals. This provides a sure grip in cold weather when wearing gloves or mittens.

The 1.25” eyepiece adapter also uses a compression ring to hold eyepieces in place. The 1.25” adapter has a slanted groove cut into the outside of its focuser-side 2” barrel. This engages with the diagonal’s compression ring to act as a safety stop to keep the adapter from accidentally slipping out of the 2” diagonal should the compression ring loosen during use. Dust covers are provided for the 1.25” adapter and the diagonal’s SCT attachment ring.

This is a premium 2” enhanced aluminum diagonal for SCTs at a price less than half that of some comparable-quality competitive models. Not only does it give you 2” eyepiece capability, but you’ll see a visible improvement over performance of the usually so-so 1.25” prism diagonal supplied with many catadioptric telescopes. And all at a very affordable price.