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End Caps and Flanges

End caps and flanges are the least glamorous parts in a telescope and among the most consequential. A flange determines whether a third-party focuser will bolt to your tube at all, and a proper end cap is what keeps dust, moisture and insects out of an optical path that is difficult to clean. David Astro carries end caps and flanges in Canada, covering drawtube terminations, telescope-specific mounting plates and dust protection, held in our Canadian warehouse.

Fit here is exact rather than approximate. Send us your telescope model and focuser and we will identify the correct flange rather than leaving you to measure a bolt circle.

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Starlight Instruments 3.5" Adapter for Sky-Watcher Esprit 120/150

Connects a 3.5" Feather Touch focuser to a Sky-Watcher Esprit 120 or 150 ED APO Precision-machined from high-grade aluminum for a rigid, no-flex c...

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Starlight Instruments 3.5" Adapter for Takahashi FS128 Telescopes

Connects a 3.5" Feather Touch Focuser to a Takahashi FS128 Machined from high-quality aluminum Ensures a rigid, non-flexing connection for imaging...

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Starlight Instruments 3.5" Adapter for Takahashi FSQ106ED Telescopes

Precision-machined for the Takahashi FSQ-106ED telescope Enables mounting of a 3.5" Starlight Instruments Feather Touch Focuser Crafted from high-...

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Starlight Instruments 3.5" Adapter for Takahashi FSQ106N Telescopes

Adapts 3.5" Feather Touch focusers to the Takahashi FSQ106N Designed specifically for pre-2009 FSQ106N models Provides a rigid, thread-on connecti...

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Starlight Instruments 3.5" Adapter for Takahashi TOA 130/FS 152 Telescopes

Adapts 3.5" Feather Touch focusers to select Takahashi refractors Compatible with Takahashi TOA 130 and FS 152 optical tubes Precision-machined fr...

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Starlight Instruments 3.5" Adapter for Takahashi TOA 150 Telescopes

Adapts 3.5" Feather Touch Focusers to Takahashi TOA-150 Telescopes Precision-Machined from High-Quality Aluminum Ensures a Rigid, No-Flex Connecti...

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Starlight Instruments 3.5" Adapter for TEC Large Refractors

Connects 3.5" Feather Touch Focusers to TEC Large Refractors Precision-Machined Aluminum Construction Ensures Perfect Optical Alignment Non-Thread...

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Starlight Instruments 3.5" Adapter for Teleskop Service TS130/TS150 Photoline

Connects 3.5" Feather Touch Focusers Designed for Teleskop Service TS130 Photoline Telescopes Designed for Teleskop Service TS150 Photoline Telesc...

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Starlight Instruments 3.5" Adapter for TMB130 Telescopes

Connects 3.5" Starlight Instruments focusers to TMB130 telescopes Ensures precise, rigid optical alignment Machined from high-quality aluminum Fin...

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Starlight Instruments 3.5" Adapter for William Optics FLT132, APM 130, and TS Photoline F7 Telescopes

Connects a 3.5" Feather Touch focuser to select telescopes Compatible with William Optics FLT132 Compatible with APM 130 models Compatible with TS...

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Starlight Instruments 3.5" Adapter for William Optics FLT151, FLT152, FLT158 & TS152 Telescopes
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Starlight Instruments 3.5" Adapter for William Optics FLT151, FLT152, FLT158 & TS152 Telescopes

Connects a 3.5" Feather Touch Focuser to select William Optics telescopes Compatible with William Optics FLT151, FLT152, and FLT158 models Compati...

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Starlight Instruments 3.5" Adapter for William Optics FLT178

Connects 3.5" Starlight Instruments focusers to William Optics FLT178 telescopes Machined of the highest quality aluminum Finished in Starlight's ...

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Starlight Instruments 3.5" Base Curved w/ Leveling Screws

Custom-machined to match your telescope's tube diameter Provides a rigid, stable platform for 3.5" Feather Touch focusers Integrated leveling scre...

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Starlight Instruments 3.5" Base Flat w/ Leveling Screws

Designed for 3.5" Feather Touch Focusers Flat Base for Custom Telescope Builds Features Leveling Screws for Precise Collimation Mounting Hole Patt...

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Starlight Instruments 3.5" End Cap - for Astro-Physics Telescope Accessories

Adapts 3.5" Feather Touch focusers to Astro-Physics accessories Provides a secure 2.7" female threaded connection Eliminates flexure and tilt with...

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Starlight Instruments 3.5" End Cap Collet Style w/ 2.0" Opening

Fits all Starlight Instruments 3.5" Feather Touch focusers Provides a secure 2.0" opening for accessories Collet-style clamp ensures perfect cente...

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Starlight Instruments 3.5" End Cap for APM/TMB Reducer

Connects 3.5" Feather Touch Focusers Adapts APM/TMB Reducers Thread Specification: M82x1 Female Material: High-Grade Aluminum Machined In-House by...

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Starlight Instruments 3.5" End Cap for CFW2-7 Series/CCD Camera & Filter Wheels

Fits 3.5" Starlight Instruments Feather Touch Focusers Provides a rigid 2.0"-24TPI male threaded connection Designed for the FLI CFW2-7 Filter Whe...

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Starlight Instruments 3.5" End Cap for SBIG and FLI 5 Series/CCD Camera & Filter Wheels

Adapts 3.5" Feather Touch focusers Provides a 3.0"x24tpi male thread connection Designed for FLI 5 Series (CFW 5-7) filter wheels Compatible with ...

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Starlight Instruments 3.5" End Cap for Sky-Watcher M65 Male Threaded Accessories

Adapts 3.5" Feather Touch Focusers to Sky-Watcher accessories Provides a secure M65x1 female threaded connection Eliminates sag and tilt common wi...

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Starlight Instruments 3.5" End Cap for Stellarvue Field Flattener

Connects 3.5" Feather Touch Focusers Designed for the Stellarvue 85mm Field Flattener Machined from High-Quality Aluminum Description FAQ Speci...

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Starlight Instruments 3.5" End Cap for Takahashi 72mm Male Threaded Accessories

Adapts 3.5" Feather Touch focusers to accept Takahashi accessories Provides a female 72mm x 1mm threaded interface Ensures a rigid, non-flexing co...

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Starlight Instruments 3.5" End Cap for Takahashi Large Field Flattener

Connects 3.5" Feather Touch focusers to specific Takahashi large field flatteners Features an M92x1 thread for a secure, rigid connection Compatib...

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Starlight Instruments 3.5" End Cap for William Optics Male Threaded Accessories

Adapts 3.5" Feather Touch focusers to William Optics accessories Provides a secure M92x1mm female threaded connection Machined from high-grade alu...

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$160.00 USD - $160.00 USD
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Flanges, Terminations and Protective Caps

This collection covers three distinct jobs: mounting a focuser to a tube, terminating a drawtube in a usable thread, and sealing an opening when the equipment is not in use.

  • Telescope-specific mounting flanges: Machined plates matched to a particular tube's bolt pattern, which is what allows an aftermarket focuser to be fitted squarely.
  • Drawtube end terminations: Convert a focuser's native output to a standard thread such as M48 or M68, giving you a clean starting point for an imaging train.
  • SCT and rear-cell flanges: Adapt Schmidt-Cassegrain rear cells to threaded standards for focusers, reducers and cameras.
  • Threaded dust caps: Seal a threaded port when a camera or eyepiece is removed, keeping the interior of the drawtube clean between sessions.
  • Objective and aperture caps: Full-aperture covers, including sub-aperture stops used to reduce light for lunar viewing.
  • Blanking plates: Cover unused ports on filter wheels, focusers and rear cells to prevent stray light entering the train.

Why Choose David Astro for End Caps and Flanges

These parts either fit exactly or do not work at all, so the value is in correct identification rather than selection.

  • Model-specific identification: Tell us the telescope and focuser and we will name the flange, rather than asking you to match a bolt circle from a photograph.
  • Squareness is critical: We advise on flanges that hold a focuser perpendicular to the optical axis, because tilt introduced here shows up as one-sided star elongation you cannot process out.
  • Genuine manufacturer parts: Authorized dealer supply with full warranty and verified authenticity.
  • Replacement caps for older gear: We can often source a lost cap for a discontinued telescope through dealer channels.

End Caps and Flanges in Canada: Frequently Asked Questions

How do I identify the flange my telescope needs?

By telescope make and model rather than by measurement, since bolt circles that look similar are often a few millimetres apart. Send us the model and the focuser you intend to fit and we will specify it.

Does a flange affect image quality?

Indirectly but significantly. A flange that holds the focuser slightly off-square tilts the whole imaging train, producing elongated stars on one side of the field regardless of how well the optics perform.

Are dust caps really necessary?

Yes. Dust on an interior surface is far harder to clean than dust on an objective, and moisture that condenses inside a sealed tube takes a long time to clear. Capping every open port between sessions is cheap insurance.

Do you stock these in Canada?

Yes, anything marked in stock is held in our Canadian warehouse.

Need a specific flange?

Send us your telescope and focuser model and we will identify the exact part. Canadian stock, fast domestic shipping.