ADM Vixen Dovetail for Celestron 11" SCT: Mounting Guide
By TelescopesPlus - The #1 Online Store for Telescopes and Accessories | Published: 2026-11-01
Category: How-to Guides
Install an ADM Vixen dovetail bar on your Celestron 11" SCT with a safe, step-by-step process that covers bolt prep, alignment, and balance tips.
Quick answer
Use the ADM VC11 Vixen-style dovetail plate to replace or upgrade the bar on your Celestron 11" SCT: mount the included radius blocks to the optical tube first, then attach the plate with the correct bolts and check balance before loading the mount.
Why the ADM VC11 is a direct fit for the C11 OTA
The ADM VC11 is made specifically for the Celestron 11" optical tube assembly and ships with the two radius blocks required to mount the dovetail plate. That matters because the radius blocks match the curve of the tube, so the plate sits flush instead of stressing the tube or leaving gaps.
The plate itself measures 18 inches long, 1.72 inches wide, and 5/8 inch thick with a 12-degree dovetail angle. The 18-inch length gives you more room to slide the tube fore and aft for balance than a shorter stock bar, which is useful when you switch between visual accessories and imaging gear.
Before you start: check your mount and hardware
This guide assumes your mount accepts a Vixen-style dovetail saddle. The 12-degree dovetail angle is the Vixen profile, so it will not fit a Losmandy-only saddle without an adapter. Confirm your saddle type before removing the original bar.
You will also need the bolts that secure the radius blocks to the OTA. The product listing does not specify bolt length or thread, so reuse the fasteners from your existing dovetail bar if they are in good condition, or match them to the threaded holes in your tube. Do not guess: if the bolts are too long, they can contact the mirror or internal optics.
A note on balance and payload
A longer dovetail bar gives you more sliding range, but it does not increase your mount's payload capacity. Balance the tube with the accessories you actually use, then tighten the saddle. If you add a heavy camera or binoviewer later, recheck balance before the next session.
The ADM VC11 adds stiffness and adjustment range, but the catalog does not list its weight. If weight is critical for your setup, weigh the plate before installation and compare it with the bar you are removing.
Step-by-step installation
- Remove the existing dovetail bar: Support the OTA on a soft, clean surface and remove the bolts holding the original bar. Keep the bolts labeled or bagged so you can reuse them if they match the ADM radius blocks. Common mistake: letting the tube roll once the bar is off; chock it or have a second person steady it. Checkpoint: the tube is stable and all original fasteners are accounted for.
- Test-fit the radius blocks: Place the two radius blocks against the tube at the same hole spacing as the original bar. Confirm the curve sits flush and the mounting holes line up. Do not force a block that rocks or leaves a gap. Checkpoint: both blocks sit flat with no rocking before any bolt is tightened.
- Bolt the radius blocks to the OTA: Thread the correct bolts through the blocks into the tube by hand first. Tighten gradually in a cross pattern until snug. Stop immediately if you feel resistance that suggests the bolt is too long or cross-threaded. Common mistake: over-tightening and dimpling the tube. Checkpoint: blocks are snug, not crushed, and the tube interior is clear.
- Attach the dovetail plate to the blocks: Set the ADM plate on the blocks and install its mounting screws finger-tight. Slide the plate fore or aft to your starting balance point before final tightening. Common mistake: centering the plate by eye instead of by balance. Checkpoint: plate screws are snug and the plate can still slide if needed.
- Set balance before loading the mount: With the OTA on a bench or in the saddle loosely, slide the tube until it balances at the pivot point with your heaviest accessory installed. Mark the position, then tighten the saddle and plate screws. Recheck balance after adding or removing gear. Checkpoint: the tube holds balance without drifting when the clutch is loose.
- Final check under load: Lift the OTA by the plate and saddle to confirm nothing shifts. Then mount it on the telescope and test slow slews in both axes. Listen for creaks or slipping. If the plate moves in the saddle, stop and recheck the saddle tension and plate screws. Checkpoint: no slipping or creaking during a slow test slew.
Product facts
- ADM Accessories Vixen Style Dovetail for Celestron 11" SCT - VC11: The ADM VC11 is intended for the Celestron 11" OTA and includes two radius blocks required for mounting. You get the curved blocks that match the tube, so the plate mounts flush without extra fabrication.
ADM Accessories Vixen Style Dovetail for Celestron 11" SCT - VC11 - ADM Accessories Vixen Style Dovetail for Celestron 11" SCT - VC11: The plate measures 18 inches long, 1.72 inches wide, and 5/8 inch thick with a 12-degree dovetail angle. The 18-inch length provides more fore-aft adjustment for balancing heavy accessories, while the 12-degree angle fits Vixen-style saddles.
