Losmandy DVR108 108mm Guide Scope Rings

Product Overview

The DVR108 is a pair of 108 mm (4.25") inside-diameter rings that clamp directly onto a Losmandy D-series or Vixen-style V-series dovetail plate. Each ring uses three-point adjustment, with screws machined from 7075 aluminium — which Losmandy states is 85% stronger than 6061 — tipped with machined 1/4-inch Delrin. The rings hold tubes from 2.96" to 4.32" in diameter, mount to a dovetail without tools, and weigh 29 oz for the set. Height from the top of the dovetail plate to the centre of the rings is 3.437" on D-series plates and 3.187" on V-series.

Who It's For

These are the rings for a guide scope or a small refractor that needs to ride alongside a main instrument. Three-point adjustment is the reason to choose them over a simple clamp: it lets you aim the tube rather than merely hold it, which is what makes acquiring a guide star quick instead of a hunt. The Delrin tips bear on the tube without marking it, and the quick dovetail mounting means the whole assembly comes off in one piece at the end of the night.

Key Features & Design

• 108 mm (4.25") inside diameter, holding tubes from 2.96" to 4.32".
• Three-point adjustment per ring, so the tube can be aimed as well as clamped.
• 7075 aluminium adjustment screws — Losmandy states 85% stronger than 6061 — with machined 1/4" Delrin tips.
• Two rings per set, at 29 oz.
• Quick dovetail mounting, no tools needed, onto D-series or Vixen-style V-series plates.
• Height to ring centre: 3.437" above a D plate, 3.187" above a V plate.
• Machined aluminium throughout.

Recommended Uses

Mounting a guide scope alongside a main imaging telescope. Carrying a small refractor as a second instrument on a side-by-side plate. Aiming a guide scope onto a chosen star without moving the main tube. Holding a finder, solar scope or camera lens assembly within the 2.96" to 4.32" diameter range.

Compatibility and Accessory Notes

• Tube diameter: 2.96" to 4.32" — about 75 mm to 110 mm. Below that range the tube will not reach the Delrin tips; above it the ring will not close.
• Plates: Losmandy D-series — the 14", 19" and 24" — and Vixen-style V-series such as the 11" and 14".
• Guide camera: the DVR66 ring adds a third ring to steady the camera at the back of the guide scope, for tubes from 3/4" to about 2.6".
• Complete set: the DVR108/66 is the three-ring package — two rings for the guide scope and one for the camera — supplied together.
• Side-by-side: on the DVSBS these rings can carry a full second instrument rather than just a guide scope.

Good to Know Before You Order

• Measure your tube before ordering. The usable range is 2.96" to 4.32" — send us the guide scope model and we will check it against that.
• Three-point adjustment is aiming, not just clamping. It is what makes these rings worth their price over a fixed clamp, and it does mean taking a minute to set the tube square before you rely on it.
• The rings add height. 3.437" to ring centre above a D plate raises the guide scope well clear of the main tube, which is usually what you want — but it also puts mass further from the declination axis.
• A guide camera hanging off the back wants support. That is what the DVR66 ring is for, and the DVR108/66 set bundles it.
• Specifications are Losmandy's published figures.

Frequently Asked Questions

Is it difficult to set up?

No. The rings clamp onto the dovetail by hand, the tube goes in, and the three adjustment screws on each ring are set to hold and aim it. No tools are needed for the dovetail mounting.

What tube diameters do they take?

2.96" to 4.32", which covers most 80 mm and many 100 mm guide scopes and small refractors.

Do they work on Vixen plates?

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

Will they mark my tube?

The adjustment screws have machined Delrin tips, which bear on the tube rather than metal on paint.

Do I need the third ring?

Only if a camera hangs off the back of the guide scope and you want it steadied. The DVR66 covers that, or buy the DVR108/66 set from the start.

Bottom Line

In short: a pair of 108 mm three-point adjustable rings, 2.96" to 4.32" tube range, 7075 screws with Delrin tips, 29 oz the set, clamping to any D or Vixen-style V plate without tools.