Skip to content
Price match 30-day returns* Talk to an astronomer before you buy
Tele Vue 2.4" Accessory Tube - 0.040" (1mm) 1
Tele Vue 2.4" Accessory Tube - 0.040" (1mm) 2
Tele Vue 2.4" Accessory Tube - 0.040" (1mm) 1
Tele Vue 2.4" Accessory Tube - 0.040" (1mm) 2

Tele Vue 2.4" Accessory Tube - 0.040" (1mm)

by TeleVue
SKU TV-TLF-0040
CA$32.00 - CA$32.00
CA$32.00
CA$32.00 - CA$32.00
CA$32.00
Price Match Policy!
  • Extension Provided: 1mm (0.040")
  • Accessory Standard: Tele Vue 2.4" Imaging System
  • Connection Type: Non-threaded spacer
  • Material: Black Anodized Aluminum
Backordered
Request Stock Alert
Availability Info
Qualifies for FREE Shipping in Canada on orders over $500.
Vignetting Calculator

Will your imaging train vignette?

Check which filter and adapter sizes clear the sensor with the Tele Vue 2.4" Accessory Tube - 0.040" (1mm), and how much light the corners lose.

Check vignetting
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Warranty

  • Achieve Perfect Spacing in Your Tele Vue Imaging System

    The Tele Vue 2.4" Accessory Tube (TLF-0040) is a precision 1mm spacer designed to solve the critical challenge of achieving exact back focus in high-performance imaging trains. For astrophotographers using Tele Vue NP-series refractors with reducers or flatteners, this component provides the small, calibrated adjustment needed to produce perfectly sharp stars across the entire sensor.

    The Critical Millimeter for a Flat Field

    Modern field flatteners and focal reducers have exacting back focus requirements, where even a single millimeter of error can result in elongated stars at the edge of your frame. The TLF-0040 accessory tube provides a precise 1mm (0.040") of optical path length, allowing you to methodically fine-tune the distance between your corrector and sensor. This small, rigid extension is often the key to transitioning from a good image to a great one, ensuring your optical system performs to its theoretical limit.

    System Integrity and Flexure-Free Connection

    This spacer is built as an integral part of the Tele Vue 2.4" imaging system. It is non-threaded and sits on the 2.4" accessory thread, clamped between threaded components rather than held by compression rings or slip-fit adapters. This clamped, threaded assembly is essential for maintaining perfect optical alignment and eliminating the possibility of tilt or flexure, which can ruin long exposures. The black anodized aluminum construction matches the fit and finish of your Tele Vue focuser and other accessories, ensuring a seamless and rigid imaging train from the focuser to the camera.

    The primary limitation of this accessory is its specificity. It is not a general-purpose extension tube; it is engineered exclusively for the Tele Vue 2.4" accessory ecosystem. Its value is realized when used with Tele Vue's large format correctors and adapters to achieve a prescribed optical distance.

  • How do I know if I need a 1mm spacer for my Tele Vue setup?

    If your images show sharp stars in the center but elongated or bloated stars in the corners, your back focus spacing is likely incorrect. A 1mm spacer is used for fine-tuning this distance. Consult your reducer or flattener's documentation for the precise back focus requirement and measure your current imaging train to see if an adjustment is needed.

    Can I stack multiple Tele Vue 2.4" accessory tubes?

    Yes, with one limit. The threaded extension tubes thread together, and this non-threaded 1mm spacer sits on the 2.4" accessory thread between them. Tele Vue cautions not to place more than one spacer between tubes, so for 3mm place the 1mm and 2mm (TLG-0080) spacers on either side of a threaded tube.

    Is this compatible with standard 2" accessories?

    No, this is not a 2" accessory. It is part of Tele Vue's larger 2.4" format, designed for their NP-series refractors like the NP101is and NP127is. It is sized for the 2.4" Imaging System accessory thread and will not fit standard 2" focusers or diagonals.

    What is the difference between this and a generic M48 extension?

    It is sized for Tele Vue's larger 2.4-inch format rather than M48, and it is made to sit on the 2.4" Imaging System accessory thread between Tele Vue's own threaded tubes and adapters, which is a level of mechanical precision not guaranteed by generic parts.

  • Product Code TLF-0040
    Extension Length 1mm (0.040")
    Accessory Series Tele Vue 2.4" Imaging System
    Material Black Anodized Aluminum
    Connection Type Non-threaded spacer (sits on the 2.4" accessory thread)
    Telescope-Side Connection Tele Vue 2.4" Imaging System thread
    Camera-Side Connection Tele Vue 2.4" Imaging System thread

    • Tele Vue 2.4" Accessory Tube - 0.040" (1mm)

      × 1

  • Tele Vue 5-Year Limited Warranty