Losmandy DVR108/66 Three-Ring Guide Scope Set

Product Overview

The DVR108/66 is Losmandy's complete three-ring guide scope set: two 108 mm rings to hold the guide scope and one 66 mm ring to stabilise the camera or guider at the back. The 108 mm rings take tubes from 2.96" to 4.32" with three-point adjustment; the 66 mm ring takes tubes from 3/4" to about 2.6". The set clamps to a Losmandy D-series or Vixen-style V-series plate without tools.

Who It's For

A guide scope with a camera on the back is a cantilever, and a cantilever flexes. Two rings hold the tube; the third holds the camera end, which is where the leverage is and where flexure turns into guiding error that no amount of software will fix. If you are building a guiding setup rather than assembling one from what is to hand, this is the version to buy — the three rings together cost less than the pieces bought separately at different times.

Key Features & Design

• Three rings supplied: two 108 mm for the guide scope, one 66 mm for the camera or guider.
• Three-point adjustment on the 108 mm rings, so the guide scope can be aimed.
• 7075 aluminium adjustment screws with machined 1/4" Delrin tips.
• 108 mm rings take 2.96" to 4.32" tubes; the 66 mm ring takes 3/4" to about 2.6".
• Quick dovetail mounting, no tools needed, onto D-series or Vixen-style V-series plates.
• Height to 108 mm ring centre: 3.437" above a D plate, 3.187" above a V plate.

Recommended Uses

Building a rigid guide scope assembly for long-exposure imaging. Supporting a guide camera that would otherwise cantilever off the back of a short tube. Carrying a small refractor with a camera as a second imaging instrument. Any setup where differential flexure between the main tube and the guider is the thing limiting exposure length.

Compatibility and Accessory Notes

• Guide scope diameter: 2.96" to 4.32" for the main pair of rings.
• Camera or guider diameter: 3/4" to about 2.6" for the third ring.
• Plates: Losmandy D-series — the 14", 19" and 24" — and Vixen-style V-series such as the 11" and 14". A longer plate is worth having so the rings sit clear of the main tube's rings.
• Bought separately: the same parts are the DVR108 pair and the DVR66 ring.
• Side-by-side: on the DVSBS the set can carry a full second instrument on its own saddle.

Good to Know Before You Order

• Measure both the tube and the camera body. 2.96" to 4.32" for the guide scope, 3/4" to 2.6" for whatever the third ring holds — send us both and we will confirm the fit.
• The third ring only helps if it can reach the camera. On a very short guide scope there may not be room for all three rings on the plate; tell us the tube length and we will work it out with you.
• Plate length matters. Three rings need more room than two, and a 14-inch plate can get crowded once the main tube's rings are on it.
• Specifications are Losmandy's published figures.

Frequently Asked Questions

Is it difficult to set up?

No. All three rings clamp onto the dovetail by hand and slide to where they are needed. The guide scope goes into the two large rings and the camera body into the small one.

Why three rings?

The third ring supports the camera end. Without it, the camera cantilevers off the back of the guide scope and any flexure there shows up as guiding error.

What sizes does it take?

2.96" to 4.32" for the guide scope, and 3/4" to about 2.6" for the camera or guider.

Can I buy the parts separately?

Yes — the DVR108 pair and the DVR66 ring are both stocked individually.

Does it fit Vixen plates?

Yes, Losmandy D-series and Vixen-style V-series both.

Bottom Line

In short: two 108 mm three-point rings for the guide scope plus a 66 mm ring for the camera, clamping to any D or Vixen-style V plate without tools — the rigid way to build a guiding assembly.