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Mounting Hardware

Flexure is invisible until you see it in your stars. A dovetail that shifts a fraction of a millimetre under load, a guide scope on a soft bracket, a saddle clamping on one point instead of a face — each produces elongation that no processing corrects. David Astro carries mounting hardware items in Canada: dovetail bars and clamps, tube rings, saddles, side-by-side plates and adapter plates, in Canadian stock.

Getting this right is mostly a matter of matching standards and eliminating single points of contact. Tell us your tube diameter, mount saddle and payload and we will specify hardware that holds it rigidly.

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Orion Optics UK 200mm Trunion rings, spacers and blocks for 3rd party telescopes.
$151.73 - $151.73
$151.73
$151.73 - $151.73
$151.73

Orion Optics UK 200mm Trunion rings, spacers and blocks for 3rd party telescopes.

OOUK-200MM-TRUNION-RINGS-SPACERS-BLOCKS

Sized for 200mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty 200mm Trunion Rings, Spacers and B...

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$151.73 - $151.73
$151.73
$151.73 - $151.73
$151.73
Orion Optics UK 250mm Trunion rings and blocks to fit OOUK 10" telescopes
$126.31 - $126.31
$126.31
$126.31 - $126.31
$126.31

Orion Optics UK 250mm Trunion rings and blocks to fit OOUK 10" telescopes

OOUK-250MM-TRUNION-RINGS-BLOCKS-OOUK

Sized for 250mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty Trunion Rings and Blocks -- OOUK 1...

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$126.31 - $126.31
$126.31
$126.31 - $126.31
$126.31
Orion Optics UK 250mm Trunion rings, spacers and blocks for 3rd party telescopes.
$160.56 - $160.56
$160.56
$160.56 - $160.56
$160.56

Orion Optics UK 250mm Trunion rings, spacers and blocks for 3rd party telescopes.

OOUK-250MM-TRUNION-RINGS-SPACERS-BLOCKS

Sized for 250mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty 250mm Trunion Rings, Spacers and B...

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$160.56 - $160.56
$160.56
$160.56 - $160.56
$160.56
Orion Optics UK 300mm Trunion rings and blocks to fit OOUK 12" telescopes
$147.03 - $147.03
$147.03
$147.03 - $147.03
$147.03

Orion Optics UK 300mm Trunion rings and blocks to fit OOUK 12" telescopes

OOUK-300MM-TRUNION-RINGS-BLOCKS-OOUK

Sized for 300mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty Trunion Rings and Blocks -- OOUK 1...

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$147.03 - $147.03
$147.03
$147.03 - $147.03
$147.03
Orion Optics UK 300mm Trunion rings, spacers and blocks for 3rd party telescopes.
$181.28 - $181.28
$181.28
$181.28 - $181.28
$181.28

Orion Optics UK 300mm Trunion rings, spacers and blocks for 3rd party telescopes.

OOUK-300MM-TRUNION-RINGS-SPACERS-BLOCKS

Sized for 300mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty 300mm Trunion Rings, Spacers and B...

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$181.28 - $181.28
$181.28
$181.28 - $181.28
$181.28
Orion Optics UK 350mm Trunion rings and blocks to fit OOUK 14" telescopes
$153.18 - $153.18
$153.18
$153.18 - $153.18
$153.18

Orion Optics UK 350mm Trunion rings and blocks to fit OOUK 14" telescopes

OOUK-350MM-TRUNION-RINGS-BLOCKS-OOUK

Sized for 350mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty Trunion Rings and Blocks -- OOUK 1...

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$153.18 - $153.18
$153.18
$153.18 - $153.18
$153.18
Orion Optics UK 350mm Trunion rings, spacers and blocks for 3rd party telescopes.
$214.83 - $214.83
$214.83
$214.83 - $214.83
$214.83

Orion Optics UK 350mm Trunion rings, spacers and blocks for 3rd party telescopes.

OOUK-350MM-TRUNION-RINGS-SPACERS-BLOCKS

Sized for 350mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty 350mm Trunion Rings, Spacers and B...

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$214.83 - $214.83
$214.83
$214.83 - $214.83
$214.83
Orion Optics UK 400mm Trunion rings and blocks to fit OOUK 16" telescopes
$181.95 - $181.95
$181.95
$181.95 - $181.95
$181.95

Orion Optics UK 400mm Trunion rings and blocks to fit OOUK 16" telescopes

OOUK-400MM-TRUNION-RINGS-BLOCKS-OOUK

Sized for 400mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty Trunion Rings and Blocks -- OOUK 1...

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$181.95 - $181.95
$181.95
$181.95 - $181.95
$181.95
Orion Optics UK 400mm Trunion rings, spacers and blocks for 3rd party telescopes.
$243.60 - $243.60
$243.60
$243.60 - $243.60
$243.60

Orion Optics UK 400mm Trunion rings, spacers and blocks for 3rd party telescopes.

OOUK-400MM-TRUNION-RINGS-SPACERS-BLOCKS

Sized for 400mm Dobsonian mounts CNC machined in the UK Description Specifications In the Box Warranty 400mm Trunion Rings, Spacers and B...

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$243.60 - $243.60
$243.60
$243.60 - $243.60
$243.60
Orion Optics UK Base Plate - 250mm Length
$133.71 - $133.71
$133.71
$163.71
$163.71 - $163.71
$163.71

Orion Optics UK Base Plate - 250mm Length

OOUK-BASE-PLATE-250MM-4-WIDE

Length: 250mm Width: 4 inches Thickness: 10mm Provides a stable, non-flexing mounting surface Ideal for custom telescope and astrophotography setu...

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$133.71 - $133.71
$133.71
$163.71
$163.71 - $163.71
$163.71
Orion Optics UK Base Plate - 400mm Length
$192.90 - $192.90
$192.90
$222.90
$222.90 - $222.90
$222.90

Orion Optics UK Base Plate - 400mm Length

OOUK-BASE-PLATE-400MM-4-WIDE

400mm Total Length Provides a Solid Connection Between OTA and Mount Engineered to Minimize Mechanical Flexure Designed for Orion Optics UK Telesc...

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$192.90 - $192.90
$192.90
$222.90
$222.90 - $222.90
$222.90
Orion Optics UK Base Plate 300mm length
$155.91 - $155.91
$155.91
$185.91
$185.91 - $185.91
$185.91

Orion Optics UK Base Plate 300mm length

OOUK-BASE-PLATE-300MM-4-WIDE

Engineered by Orion Optics UK Provides a Rigid, Flex-Free Mounting Platform Connects Telescope Tube Rings to Mount Saddles Solid Metal Constructio...

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$155.91 - $155.91
$155.91
$185.91
$185.91 - $185.91
$185.91
Orion Optics UK Base Plate 350mm length
$178.10 - $178.10
$178.10
$208.10
$208.10 - $208.10
$208.10

Orion Optics UK Base Plate 350mm length

OOUK-BASE-PLATE-350MM-4-WIDE

Provides a solid, flat mounting surface for telescope tube rings Engineered to eliminate flexure in the optical train Serves as the core structura...

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$178.10 - $178.10
$178.10
$208.10
$208.10 - $208.10
$208.10
Orion Optics UK Base Plate 450mm length
$259.48 - $259.48
$259.48
$289.48
$289.48 - $289.48
$289.48

Orion Optics UK Base Plate 450mm length

OOUK-BASE-PLATE-450MM-4-WIDE

450mm Length 4-inch Width 10mm Thickness Provides a rigid mounting surface for telescope tube rings Description FAQ Specifications In the Box W...

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$259.48 - $259.48
$259.48
$289.48
$289.48 - $289.48
$289.48
Orion Optics UK Celestron CGEM Dovetail 3" wide plate 250mm long
$252.08 - $252.08
$252.08
$282.08
$282.08 - $282.08
$282.08

Orion Optics UK Celestron CGEM Dovetail 3" wide plate 250mm long

OOUK-CELESTRON-CGEM-DOVETAIL-3-WIDE

250mm length Fits Celestron CGEM mounts CNC machined in the UK Description Specifications In the Box Warranty 250mm Celestron CGEM Doveta...

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$252.08 - $252.08
$252.08
$282.08
$282.08 - $282.08
$282.08
Orion Optics UK Celestron CGEM Dovetail 3" wide plate 350mm long
$266.88 - $266.88
$266.88
$296.88
$296.88 - $296.88
$296.88

Orion Optics UK Celestron CGEM Dovetail 3" wide plate 350mm long

OOUK-CELESTRON-CGEM-DOVETAIL-3-WIDE-2

350mm length Fits Celestron CGEM mounts CNC machined in the UK Description Specifications In the Box Warranty 350mm Celestron CGEM Doveta...

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$266.88 - $266.88
$266.88
$296.88
$296.88 - $296.88
$296.88
Orion Optics UK Dovetail Plate for Orion Tube Cradles
$91.79 - $91.79
$91.79
$121.79
$121.79 - $121.79
$121.79

Orion Optics UK Dovetail Plate for Orion Tube Cradles

OOUK-DOVETAIL-PLATE-ORION-CRADLES-EQ5

Connects Orion Optics UK Tube Cradles to a Mount Vixen-Style Dovetail Profile Compatible with VX and IDEAL Series Telescopes Fits EQ5, EQ6, GP, an...

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$91.79 - $91.79
$91.79
$121.79
$121.79 - $121.79
$121.79
Orion Optics UK Dovetail Plate Skywatcher/Vixen 355mm
$126.72 - $126.72
$126.72
$226.72
$226.72 - $226.72
$226.72

Orion Optics UK Dovetail Plate Skywatcher/Vixen 355mm

OOUK-DOVETAIL-PLATE-43MM-X-355MM

Length: 355mm Width: 43mm Compatibility: Vixen / Sky-Watcher Style Saddles Provides Secure Mounting for Optical Tubes Description FAQ Specifica...

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$126.72 - $126.72
$126.72
$226.72
$226.72 - $226.72
$226.72
Orion Optics UK Female Losmandy Baseplate 400mm long
$380.81 - $380.81
$380.81
$410.81
$410.81 - $410.81
$410.81

Orion Optics UK Female Losmandy Baseplate 400mm long

OOUK-FEMALE-LOSMANDY-BASEPLATE-400MM

400mm length Fits Losmandy-standard mounts CNC machined in the UK Description Specifications In the Box Warranty 400mm Female Losmandy Ba...

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$380.81 - $380.81
$380.81
$410.81
$410.81 - $410.81
$410.81
Orion Optics UK Losmandy Attachment Plate - 250mm Long
$252.08 - $252.08
$252.08
$282.08
$282.08 - $282.08
$282.08

Orion Optics UK Losmandy Attachment Plate - 250mm Long

OOUK-AG8-LOSMANDY-ATTACHMENT-PLATE-250MM

250mm length for optimal balance and support Standard Losmandy D-style dovetail profile Machined from a single piece of solid, aero-grade aluminum...

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$252.08 - $252.08
$252.08
$282.08
$282.08 - $282.08
$282.08
Orion Optics UK Losmandy Attachment Plate - 300mm Long (AG10)
$259.48 - $259.48
$259.48
$289.48
$289.48 - $289.48
$289.48

Orion Optics UK Losmandy Attachment Plate - 300mm Long (AG10)

OOUK-AG10-LOSMANDY-ATTACHMENT-PLATE-300MM

300mm Length Losmandy D-Style Dovetail Solid Aero-Grade Aluminum Construction Mounts Orion Optics CT & AG Telescopes Adapts CNC Rings to Vixen...

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$259.48 - $259.48
$259.48
$289.48
$289.48 - $289.48
$289.48
Orion Optics UK Losmandy Attachment Plate - 350mm Long
$266.88 - $266.88
$266.88
$296.88
$296.88 - $296.88
$296.88

Orion Optics UK Losmandy Attachment Plate - 350mm Long

OOUK-AG10-LOSMANDY-ATTACHMENT-PLATE-350MM

Losmandy D-Style Dovetail Profile 350mm Overall Length Solid Aerospace-Grade Aluminum Construction Direct Fit for Losmandy & Paramount Mounts ...

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$266.88 - $266.88
$266.88
$296.88
$296.88 - $296.88
$296.88
Orion Optics UK Losmandy Attachment Plate - 450mm Long
$281.67 - $281.67
$281.67
$311.67
$311.67 - $311.67
$311.67

Orion Optics UK Losmandy Attachment Plate - 450mm Long

OOUK-LOSMANDY-BASEPLATE-450MM

450mm Length for Large Aperture Telescopes Losmandy D-Style Dovetail Profile Machined from Solid Aerospace-Grade Aluminum Designed for Orion Optic...

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$281.67 - $281.67
$281.67
$311.67
$311.67 - $311.67
$311.67
Orion Optics UK Losmandy Attachment Plate 300mm Long
$259.48 - $259.48
$259.48
$289.48
$289.48 - $289.48
$289.48

Orion Optics UK Losmandy Attachment Plate 300mm Long

OOUK-AG8-LOSMANDY-ATTACHMENT-PLATE-300MM

300mm Length Losmandy D-Style Dovetail Solid Aero-Grade Aluminum Compatible with Losmandy & Paramount Mounts Designed for Orion Optics UK CT &...

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$259.48 - $259.48
$259.48
$289.48
$289.48 - $289.48
$289.48

Dovetail Standards and Building a Rigid Connection

Nearly all mounting hardware follows one of two dovetail standards, and mixing them without the correct clamp is the most common cause of a telescope sitting loose on an otherwise good mount.

  • Vixen-style dovetail (approximately 44 mm): The lighter standard, fine for small refractors and visual loads up to a few kilograms.
  • Losmandy-style dovetail (approximately 75 mm): The wider, stiffer standard used for heavier optics and imaging trains where flexure must be minimized.
  • Tube rings: Sized to the tube's outer diameter and lined to protect it; rings allow rotation for framing without unbolting the optic.
  • Mount saddles: The receiving clamp on the mount head. Dual-fit saddles accept both standards, and face-clamping designs grip more securely than a single point screw.
  • Side-by-side plates: Carry two optical tubes on one mount with balance adjustment in both axes.
  • Adapter plates: Convert between standards, add accessory mounting points, or raise a guide scope clear of an obstruction.

Why Choose David Astro for Mounting Hardware

Rigidity is cumulative. Every joint between the optic and the mount either holds or contributes to the error you spend the night chasing.

  • Standard matching: We confirm your mount's saddle type and specify a dovetail that fits it fully, rather than one that seats on an edge.
  • Flexure diagnosis: If your guiding shows drift that guiding corrections cannot fix, we will look at the mechanical chain with you — usually it is a guide scope bracket or an undersized dovetail.
  • Tube diameter fitting: Rings are matched to actual measured outer diameter, since nominal aperture and tube diameter are not the same number.
  • Authorized dealer: Genuine hardware with full manufacturer warranty, shipped from Canadian stock.
  • No cross-border fees: Canadian orders ship domestically with no duties or brokerage charges.

Mounting Hardware in Canada — Frequently Asked Questions

Vixen or Losmandy dovetail?
Losmandy for anything above roughly 7 kg or for imaging where flexure matters. Vixen is adequate for smaller refractors and visual use, and is lighter and more common on entry-level mounts.
Can I put a Vixen bar in a Losmandy saddle?
Only with a dual-fit saddle or an adapter clamp. Forcing a narrow bar into a wide clamp results in point contact, which is exactly the condition that causes slipping under load.
Why do my stars elongate only on one side of a meridian flip?
That pattern usually indicates differential flexure rather than tracking error. Check the guide scope bracket, the dovetail seating and the focuser drawtube, in that order.
How do I size tube rings?
By the tube's outer diameter, not aperture. Measure the tube itself, or tell us the exact telescope model and we will confirm the correct ring size.

Chasing flexure?

Tell us your tube, mount and payload and we will specify hardware that holds it solid. Ships from Canada with expert support.