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Precision Spacing for Flawless Astrophotos
The Tele Vue Set of 6 2.4" Accessory Tubes is an essential toolkit for astrophotographers using Tele Vue's large-format "is" refractors, providing the mechanical precision required to achieve perfect back focus. This comprehensive set allows you to rigidly and accurately set the distance between your reducer, flattener, or corrector and your camera sensor. Getting this distance right is not just a recommendation, it is a fundamental requirement for achieving sharp, coma-free stars across the entire photographic field.
Modern correctors and reducers are designed with a specific, optimal back-focus distance, often 55mm, but this can vary. This set gives you the modular components to bridge the gap between your camera's native back focus and the optical requirement of your imaging train. By combining threaded tubes for major adjustments and unthreaded shims for fine-tuning, you can build the exact spacing your system needs, down to the millimeter, eliminating a critical source of image degradation.
Four Threaded Extension Tubes for Secure Connections
The core of the set consists of four threaded extension tubes, providing 6.4mm (0.25"), 9.5mm (0.375"), 12.7mm (0.50"), and 25.4mm (1.0") of spacing. Each tube features the robust Tele Vue 2.4" imaging system thread on both male and female ends. This ensures a secure, tilt-free connection that maintains the rigidity of your imaging train, which is critical when supporting heavy cameras and filter wheels.
Two Unthreaded Spacers for Millimeter-Level Accuracy
When your required spacing falls between the lengths of the threaded tubes, the two included unthreaded spacers provide the solution. The 1mm and 2mm shims are designed to be placed between any two threaded components, allowing you to dial in your back focus with high precision. This fine control is often the difference between good edge-of-field star shapes and perfect ones.
Durable and Lightweight Aluminum Construction
Every component in the set is machined from black anodized aluminum. This material provides an excellent balance of strength and low weight, ensuring your focuser is not overburdened. The anodized finish adds a layer of durability and corrosion resistance, protecting your investment for years of use in the field.
Anti-Reflection Threads to Maximize Contrast
To preserve the high contrast delivered by Tele Vue optics, the interior of the threaded extension tubes features micro-baffles. These anti-reflection threads are designed to trap any stray light that might enter the optical path. This small but critical detail prevents internal reflections from scattering light and reducing the contrast of your final image, ensuring deep black skies and faint details are not washed out.
Designed for the Tele Vue 2.4" Imaging System
This set is specifically engineered for the large-format focusers found on Tele Vue NP101is and NP127is refractors. These telescopes, designed for wide-field imaging with large sensors, have a 2.4" diameter drawtube exit to minimize vignetting. This accessory tube set integrates perfectly, maintaining the full, unvignetted light path from the corrector to your camera sensor.
Modular Design for Ultimate Versatility
The true power of this set is its modularity. The six different lengths can be stacked in various combinations to create dozens of unique spacing distances. Whether you are using a Tele Vue 0.8x reducer, a Large Field Corrector, or third-party accessories, this kit provides the flexibility to adapt to nearly any back-focus requirement you encounter, making it a permanent and indispensable part of your imaging toolkit.
An Essential Tool for Serious Imagers
While it may seem like a simple set of tubes, achieving correct back focus is a non-negotiable part of serious astrophotography. A small error in spacing can introduce significant aberrations, wasting precious imaging time. The Tele Vue Set of 6 Accessory Tubes is the professional solution, providing a reliable, repeatable, and precise method for optimizing your optical system for the best possible performance.
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What is the main purpose of the Tele Vue 2.4" Accessory Tube Set?
This set allows astrophotographers to precisely adjust the back-focus distance between their camera sensor and a field flattener or reducer. Achieving the correct spacing, often 55mm, is critical for obtaining sharp, coma-free stars across the entire image field with Tele Vue "is" refractors.
Will these tubes work with a standard 2" focuser?
No, these tubes use Tele Vue's specific 2.4" imaging system thread. They are designed for the larger focusers on NP101is, NP127is, and other "is" series telescopes to prevent vignetting with large camera sensors.
How do I use the unthreaded 1mm and 2mm spacers?
The unthreaded spacers are used for fine-tuning. You simply sandwich them between two of the threaded extension tubes or between an extension tube and your camera adapter. The pressure from tightening the threaded components holds the spacer securely in place.
Can I stack multiple tubes together?
Yes, the tubes are designed to be stacked. You can combine multiple threaded tubes and spacers to build the exact length required by your specific camera and corrector combination, offering a high degree of modularity.
Why are anti-reflection threads important?
The internal threads act as light baffles, trapping stray light that could otherwise cause internal reflections within the imaging train. This helps to maintain maximum image contrast, resulting in darker sky backgrounds and more visible faint detail in your astrophotos.
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| Compatibility |
Tele Vue 2.4" Imaging System Focusers |
| Thread |
Tele Vue 2.4" Imaging System Thread (2.56"-24tpi nominal) |
| Material |
Black Anodized Aluminum |
| Threaded Tube Lengths |
6.4mm (0.25"), 9.5mm (0.375"), 12.7mm (0.50"), 25.4mm (1.0") |
| Unthreaded Spacer Thicknesses |
1mm (0.040"), 2mm (0.080") |
| Total Components |
6 |
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25.4mm (1.0") Threaded Extension Tube (TLD-1000)
× 1
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12.7mm (0.50") Threaded Extension Tube (TLC-0500)
× 1
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9.5mm (0.375") Threaded Extension Tube (TLB-0375)
× 1
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6.4mm (0.25") Threaded Extension Tube (TLA-0250)
× 1
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2mm (0.080") Unthreaded Spacer (TLG-0080)
× 1
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1mm (0.040") Unthreaded Spacer (TLF-0040)
× 1
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Tele Vue 5-Year Limited Warranty
