Sky-Watcher 355mm Universal D-Plate Losmandy-Style Dovetail Bar

Product Overview

The Sky-Watcher 355mm Universal D-plate is the long version of their Losmandy-style dovetail bar — 14 inches of rail drilled with a wide array of mounting holes so it carries tube rings and mounting feet from a broad range of telescopes rather than one model. It is anodized green to match Sky-Watcher's signature colour scheme.

Length is what you are buying here. Sky-Watcher describes the universal D-plate as a mount accessory for visual astronomers and astrophotographers looking to mount a wide variety of telescope tubes to larger mounts, and 355 mm gives widely spaced tube rings somewhere to land while leaving travel in the saddle for balance once a camera train hangs off the back.

Who It's For

This is for long tubes and heavy rigs on a Losmandy-style saddle — a large refractor or Newtonian whose rings sit far apart, a tube that arrived without a dovetail, or an imaging setup where the balance point moves a long way once the camera, filter wheel and guider are attached.

Key Features & Design

• 14" (355mm) Losmandy-style profile: the wide D-pattern bar in its long form, sized for large tubes and widely spaced rings.
• Numerous mounting holes: Sky-Watcher publishes it as drilled for mounting on a wide variety of telescopes, so the bar adapts to your ring or foot spacing rather than the other way round.
• Long balance travel: 355 mm of rail is roughly double the 180mm plate, which is what a heavy back end consumes when you slide the tube forward to rebalance.
• Anodized green finish: matches Sky-Watcher's signature colour scheme across their mount and accessory range.
• Universal rather than model-specific: the vendor sells it as a general-purpose plate for larger mounts, not as the bar for one telescope.

Recommended Uses

• Large refractors and Newtonians: tubes whose rings sit far enough apart that a short bar has nowhere to bolt.
• Imaging rigs with a heavy back end: camera, filter wheel, off-axis guider and rotator all pull the balance point rearward, and the extra length gives you somewhere to go.
• Side-by-side and dual-instrument setups: a long rail carries a second scope or camera assembly alongside the main tube.
• Visual observing on larger mounts: the same mechanical interface, no imaging assumptions attached.

Compatibility and Accessory Notes

Sky-Watcher publishes this as a Losmandy-style D-plate. It seats in a saddle cut for the wide D-profile; many larger mounts ship with a dual saddle that accepts both D and V bars, while a Vixen-only saddle takes the narrower V-plate instead. If you are not sure which saddle is on your mount, send us the mount model and we will tell you which bar it takes.

Sky-Watcher does not publish the hole spacings or thread sizes on this plate — only that there are numerous holes for a wide variety of telescopes. On any given tube the deciding question is whether your rings or mounting foot line up with holes that are actually there. Send us the model of your telescope or the centre-to-centre spacing of your tube rings and we will check the pattern against a plate in stock before it ships.

The 180mm version (S31000) is the same plate in short form and is the better fit for compact tubes where 355 mm would simply overhang the saddle.

Good to Know Before You Order

• Hole pattern is not published. Sky-Watcher states "numerous holes" without giving spacings, hole diameters or thread sizes. We can measure a plate against your ring spacing on request.
• Saddle standard is Losmandy (D). A saddle cut only for the narrow Vixen V-profile takes a V-plate; a dual saddle takes either.
• Fasteners are not published. The vendor does not state whether mounting bolts are supplied, so tube rings that came with their own hardware are worth keeping to hand.
• Length is 355 mm. On a short tube the ends of the bar will overhang the rings with nothing bearing on them, which is what the 180mm plate exists for.
• Weight is 1134 g (2.5 lb). It counts toward the mount's payload alongside the tube, camera and any guider — noticeably more than the 599 g of the short plate.
• Vendor description text carries a typo. Sky-Watcher's paragraph on this listing opens with "The 180mm Universal D-Plate..." while the title, the product bullets and the part number all state 14" (355mm). The 355 mm figure is the one that matches this SKU.

Frequently Asked Questions

Is it difficult to set up?

No. Bolts pass through the plate into your tube rings or the telescope's mounting foot, and the finished assembly slides into the mount's saddle and clamps. There is nothing to adjust or align beyond sliding the tube for balance.

Is this Vixen or Losmandy?

Losmandy. Sky-Watcher publishes it as a Losmandy-style D-plate — the wide profile, which is what their "D" designation refers to.

Will it fit my telescope?

Sky-Watcher publishes it as universal, drilled for a wide variety of telescopes, and does not publish the spacings. What decides it is whether your rings or mounting foot line up with the holes. Send us your telescope model or the ring spacing and we will work it out with you.

Should I take the 355mm or the 180mm?

Ring spacing and balance range decide it. Widely spaced rings on a long tube, or a heavy camera train that drags the balance point well back, is what the 355mm plate is for. A short refractor or a compact catadioptric sits comfortably on the 180mm.

Why does the description mention 180mm?

That line is a copy-and-paste carry-over on Sky-Watcher's page. This SKU, S31010, is the 14" (355mm) plate.

Bottom Line

A 14-inch Losmandy-style bar with an open hole pattern in Sky-Watcher green — the long rail for big tubes, widely spaced rings and imaging trains that need room to balance. Send us your telescope or your ring spacing and we will confirm the holes line up before it leaves the shop.