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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 accessory tube is built as an integral part of the Tele Vue 2.4" imaging system, connecting via secure threads rather than compression rings or slip-fit adapters. This threaded connection 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.
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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, these tubes are designed to be stacked. You can thread multiple tubes together to achieve a specific custom spacing, such as combining a 1mm (TLF-0040) and 2mm (TLG-0080) tube for 3mm of extension, all while maintaining a rigid, flex-free connection.
Will this spacer cause vignetting with a full-frame camera?
No, the Tele Vue 2.4" imaging system is designed to provide a fully illuminated field for sensors up to 52mm diagonal. This 1mm spacer maintains that clear aperture, ensuring no additional vignetting when used as part of the complete Tele Vue imaging train.
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 uses proprietary threads and will not connect to standard 2" focusers or diagonals.
What is the difference between this and a generic M48 extension?
This tube has a much larger 2.4-inch clear aperture to prevent vignetting with large sensors and fast optics. More importantly, its proprietary threading ensures a perfect, tilt-free fit with Tele Vue's own focusers and adapters, which is a level of mechanical precision not guaranteed by generic parts.
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| Product Code |
TLF-0040 |
| Extension Length |
1mm (0.040") |
| Accessory Series |
Tele Vue 2.4" Imaging System |
| Material |
Black Anodized Aluminum |
| Connection Type |
Threaded Male/Female |
| Outer Diameter |
~2.7" (68.6mm) |
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Tele Vue 2.4" Accessory Tube - 0.040" (1mm)
× 1
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Tele Vue 5-Year Limited Warranty
