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Black anodised aluminium cylinder, 80mm long with M68 threads and 62mm clear aperture

Baader Planetarium

Baader Planetarium 80mm M68 Extension Tube

SKU CH-W192-DDNGN

An 80 mm M68 extension tube with a 62 mm clear aperture for precise back-focus adjustment on eyepiece projection and Fluoride Flatfield Convertor systems

  • 62mm clear aperture reduces vignetting for brighter deep-sky images
  • 80mm length provides precise back-focus adjustment across telescope configurations
  • M68 threads ensure secure, stable connection to imaging accessories
  • Compatible with classic eyepiece projection and Fluoride Flatfield Convertors
  • Rigid construction minimises flexure to keep planetary detail sharp

Essential astrophotography spacer

The Baader Planetarium 80mm M68 Extension Tube is a precision-machined spacer designed for classic eyepiece projection and Fluoride Flatfield Convertor systems. It provides an exact 80mm optical path extension with a 62mm clear aperture that minimises vignetting. M68 threads on both ends ensure a rigid, light-tight connection between telescope and imaging accessories. This new accessory is built for astronomers who need accurate back-focus control.

Suited for eyepiece projection and FFC users

Astrophotographers using classic eyepiece projection or Fluoride Flatfield Convertors gain the precise spacing required for optimal focus and image scale. The 62mm aperture supports full-frame sensors without mechanical vignetting. Observers whose imaging train uses a different thread standard or who require a shorter or longer back-focus distance cannot use this tube.

Deciding specification: 80mm length with M68 threads

The single value that determines fit is the 80mm extension length combined with M68 threading on both ends. If your optical train demands exactly this spacing and thread interface, the tube delivers secure alignment and maximum light throughput. Any other required length or thread size makes this part incompatible.

How it compares

Measured against everything we stock in Binoculars, Scopes & Sights, at today’s prices. Recalculated every night.

Price $112.99
Typical for this category: the median of 1,401 items is $93.99.

Specifications

No published specifications for this item yet.

Questions about this item

Will the 62 mm clear aperture of this 80 mm M68 tube need cleaning or replacement over time?

The 62 mm clear aperture is a fixed opening in the tube wall; it has no moving parts or consumables, so it does not require scheduled cleaning or replacement under normal use.

What limit appears first when this 80 mm M68 extension tube is used continuously for long imaging sessions?

The tube itself is a passive spacer with no electronics or moving surfaces, so it imposes no thermal, power or mechanical limit during sustained operation.

Does the M68 threaded 80 mm extension tube generate any noise, heat or power draw when left in the optical train all day?

As a purely mechanical spacer with no motors, fans or electronics, it produces zero noise, zero heat and draws no power at any time.

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