Farpoint 14 Inch 57.3 Series Universal Dovetail Plate (Original Radian Bar)

Product Overview

This is the original Radian bar: a 14″ light-weighted universal dovetail plate in the D-size (Losmandy) profile, now sold direct by the company that has always machined it. Farpoint produced these bars for OPT, which marketed them under the Radian Telescopes name; when OPT closed, Farpoint carried the line on as the 57.3 Series — same bar, same tooling, same USA machining. The plate is CNC-machined aluminum with a black anodized finish, and Farpoint publishes a 4 lb weight for the item.

Who It's For

This is a good match if you…

• are mounting an optical tube, a set of rings or an accessory cluster on a D-size Losmandy saddle.
• own a Radian bar already and want a matching second one from the same tooling.
• want mounting holes in more than one pattern so a tube with unusual hole spacing still lands on the bar.
• would rather spend payload on optics and cameras than on mounting hardware.
• need roughly 14″ of fore-and-aft travel for balancing a heavy imaging train.

Key Features & Design

• 14″ bar length: sets the ring spacing available and the balance travel inside the saddle.
• D-size (Losmandy) profile: the wider of the two common dovetail standards, used on heavy-duty equatorial saddles.
• Light-weighted construction: material is machined away between the mounting points, so the bar carries load without taking much of the mount's rated capacity.
• Universal hole pattern: a variety of mounting hole options is machined along the bar; Farpoint's product drawing shows the positions.
• Black anodized aluminum: a hard, non-reflective finish on CNC-machined aluminum.
• The original Radian tooling: the 57.3 Series is the same bar OPT sold as Radian, produced on the same tooling in the United States.

Mechanical Design

A universal bar is a compromise between stiffness and mass, and the light-weighting is where that compromise is made. Farpoint removes material from the web between the top and bottom faces while leaving the dovetail flanks and the mounting bosses full section, so bending stiffness along the bar stays high while the weight that the mount has to carry — and counterweight — stays down. The D-size profile contributes to that: a wider dovetail gives the saddle clamp a longer moment arm to resist tube droop than a Vixen bar of the same length. The variety of hole positions along the 14″ length is what makes the bar universal rather than model-specific — rings, radius blocks and accessory clamps with different spacings all find holes, and the exact positions are on Farpoint's product drawing.

Recommended Uses

• Carrying a refractor in rings on a Losmandy G-11, a Celestron CGX, or another D-size saddle.
• Mounting an SCT on radius blocks such as the Farpoint FDM12R or FDM14R.
• Serving as a top bar for a guide scope, a second camera or a finder cluster.
• Balancing a long imaging train by sliding the whole assembly fore and aft in the saddle.
• Replacing a Radian bar on an existing setup where matching hardware is wanted.

Compatibility and Accessory Notes

The bar is cut to the D-size Losmandy standard, so it seats in Losmandy G-8, G-11 and Titan saddles, Celestron CGE, CGEM, CGX and CGX-L saddles, and the dual-format saddles on many iOptron, Sky-Watcher and Astro-Physics mounts. A saddle machined only for the narrower Vixen (V-size) profile takes a different bar or an adapter. On the tube side it works with any rings or blocks whose hole spacing lines up with one of the bar's hole positions, including Farpoint's own radius blocks and ring sets. Farpoint publishes the hole layout on a product drawing rather than as a spec table, and does not publish the bar's width, thickness or hole spacing in figures. If you send us your rings or tube model and their hole spacing, we will check the layout against the drawing for you.

Good to Know Before You Order

• This is the bar alone. Rings, radius blocks and mounting screws are separate items.
• The profile is D-size, not Vixen. A Vixen-only saddle calls for an adapter or a different bar.
• Hole positions are published as a drawing, not as dimensions. We are glad to look them up against your hardware before you order.
• Farpoint publishes no width or thickness figures for the bar. The 14″ length is the only published dimension.
• The published weight is 4 lb. Farpoint lists the same 4 lb figure for the 21.5″ bar, so this is best read as a shipping figure rather than the net weight of the plate.
• The 57.3 Series and the Radian bar are the same product. The name changed when OPT closed; the bar did not.

Frequently Asked Questions

Is it difficult to install?

No. The bar bolts to rings or radius blocks through the holes already machined in it, and then slides into the saddle and is clamped. It is hand-tool work.

Is this the same as the Radian 14″ bar?

Yes. Farpoint machined the Radian bars for OPT and continued the line as the 57.3 Series after OPT closed, using the same tooling and the same USA machining.

Will it fit a Vixen saddle?

It is a D-size bar, so it fits saddles cut for the Losmandy profile and dual-format saddles. A Vixen-only clamp is a narrower standard.

What hole spacing does it have?

The bar carries a variety of mounting hole options along its length rather than one fixed spacing. Farpoint publishes the positions on a product drawing, and we can check a specific spacing against it.

How long a tube does 14″ suit?

The 14″ length sets both the maximum ring spacing and the balance travel. Longer tubes and heavier imaging trains generally favour the 21.5″ version of the same bar.

Bottom Line

In short: the original 14″ Radian light-weighted universal dovetail plate, CNC-machined in the USA in black anodized aluminum to the D-size Losmandy standard, now carrying Farpoint's 57.3 Series name.