Meade SC Thread to 2 Inch Adapter: Connecting SCT Accessories

By TelescopesPlus - The #1 Online Store for Telescopes and Accessories | Published: 2026-11-03

Category: Guide pratiche

Learn how to install the Meade SC Thread to 2 Inch Adapter (07085) on your SCT and connect 2-inch diagonals or accessories safely. Step-by-step guidance and practical tips.

Quick answer

To connect 2-inch accessories to your Schmidt-Cassegrain telescope, thread the Meade SC Thread to 2 Inch Adapter (07085) onto the rear cell's 2-inch threads, then secure your 2-inch diagonal or eyepiece with the adapter's two ball-head thumbscrews. Always support the load and check thread engagement before adding heavy gear.

Why the rear-cell thread matters for 2-inch accessories

Schmidt-Cassegrain telescopes use a large threaded rear port, often called the visual back thread. Many stock visual backs accept only 1.25-inch accessories. The Meade 07085 adapter converts those 2-inch diameter rear-cell threads to a standard 2-inch slip-fit opening, letting you use 2-inch diagonals, eyepieces, and other accessories without changing the telescope's backend. This is a common SCT visual back upgrade for observers who want a wider field of view or heavier accessories.

The adapter is 2.9 inches long and weighs 7 ounces, so it adds some length and weight behind the scope. That extra length can affect balance and clearance, especially when you attach a large 2-inch diagonal and eyepiece. Keep this in mind as you plan your setup.

When this adapter is the right choice—and when it isn't

This adapter fits all LX and RCX telescopes with 2-inch rear-cell threads, according to the manufacturer. If you already have a 2-inch visual back or a larger thread pattern, you may not need it. Also, if your telescope has a different thread size or a non-standard rear port, this adapter won't fit. Always confirm your scope's rear thread diameter before purchasing.

Because the adapter uses two ball-head thumbscrews to hold accessories, it relies on friction and screw pressure rather than a compression ring. That's generally fine for visual use, but if you plan to hang very heavy imaging trains, consider a dedicated visual back with a compression ring or a threaded connection for extra security.

Step-by-step installation and connection

Prepare the telescope and adapter: Point the telescope horizontally or slightly downward to prevent dust from settling on the rear lens, then remove any existing visual back or accessory from the rear cell. Inspect the adapter threads and the telescope's rear threads for debris; wipe them with a lint-free cloth if needed. A clean thread prevents cross-threading and ensures a secure fit.
Thread the adapter onto the rear cell: Carefully start threading the adapter onto the rear cell by hand, turning counterclockwise until you feel the threads engage, then turn clockwise. Tighten firmly but do not overtighten; the adapter should seat fully against the rear cell without forcing. If the adapter feels loose or wobbly after tightening, stop and check for crossed threads or an incompatible thread pitch.
Attach your 2-inch diagonal or accessory: Loosen the two ball-head thumbscrews on the adapter's slip-fit side, insert the nosepiece of your 2-inch diagonal or accessory fully, and tighten both thumbscrews evenly. Alternate between them to keep the accessory centered. Tightening one screw fully before the other can tilt the accessory and degrade optical alignment.
Check balance and clearance: With the accessory attached, move the telescope through its full range of motion—especially near the zenith—to ensure the adapter and accessory do not hit the mount or tripod. Rebalance the telescope if needed by adjusting the tube's position or adding counterweights. The added length of 2.9 inches and 7 ounces can shift the center of gravity; always test before a observing session.
Verify security before observing: Gently tug on the accessory to confirm it is held firmly, and re-check the thumbscrews after the first few minutes of use as temperature changes can loosen them slightly. For heavy setups, consider adding a safety strap or using a compression-ring visual back. Never lift the telescope by the adapter or attached accessories; always support the optical tube itself.

Product facts

Meade SC Thread to 2 Inch Accessory Adapter - 07085: The adapter has 2-inch diameter rear-cell threads on one side and a 2-inch slip-fit opening with two ball-head thumbscrews on the other. This lets you attach standard 2-inch diagonals and accessories to SCTs that lack a 2-inch visual back, but you must tighten both thumbscrews evenly to avoid tilting the accessory.
Meade SC Thread to 2 Inch Accessory Adapter - 07085