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Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)
Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)

Baader Planetarium Alan Gee Universal 2" Telecompressor (UAG II)

by Baader Planetarium
SKU BAA-2454405
CA$286.00 - CA$286.00
CA$286.00
CA$286.00 - CA$286.00
CA$286.00
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  • Unique telecompressor designed for visual use with binoviewers
  • Based on the flat-field Alan Gee design by Roland Christen of AstroPhysics
  • Enables wide, 2-inch-like fields of view with 1.25" binoviewer systems
  • Housed in a standard 2" nosepiece with a T-2 thread on the telescope side
  • Compatible with Schmidt-Cassegrain and EdgeHD optical tubes
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  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • Alan Gee Universal 2" Telecompressor (UAG II)

    The Alan Gee Universal 2" Telecompressor (UAG II) is a unique focal reducer, derived from a Roland Christen design, engineered to deliver a flat, wide field of view in Schmidt-Cassegrain telescopes. Its proven optical group is housed in a versatile 2" barrel with T-2 threads, making it the only telecompressor on the market specifically designed to work seamlessly with binoviewers. This configuration allows you to achieve the expansive fields of a 2" eyepiece system while using your preferred 1.25" binoviewer.

    Flat-Field Correction for 8" to 14" SCTs

    Originally designed by Roland Christen of AstroPhysics, the Alan Gee telecompressor was created to solve the dual problems of long focal ratios and field curvature in standard Schmidt-Cassegrain telescopes. The UAG II brings this powerful optical correction to a wider audience, delivering sharp, flat fields suitable for both visual observation and imaging.

    While standard reducers can increase the field of view, they often introduce other aberrations. The UAG II is designed to maintain high image quality across the field, making it an ideal match for Celestron EdgeHD telescopes and other modern SCTs where edge-to-edge sharpness is critical.

    Achieve 2" Fields with Your 1.25" Binoviewer

    The standout capability of the UAG II is its compatibility with binoviewers. For years, SCT users wanting immersive, two-eyed views were limited by the narrow fields of 1.25" systems. The UAG II eliminates this trade-off by significantly widening the field of view, creating an experience comparable to using a low-power 2" eyepiece.

    When paired with a binoviewer like the Baader Maxbright® II and wide-field 1.25" eyepieces, the UAG II can frame enormous deep-sky objects like the Andromeda Galaxy (M31) or the North American Nebula (NGC 7000) in their entirety. It provides the benefit of a 2" system without the cost and weight of a hypothetical 2" binoviewer.

    Flexible Connectivity: 2" Nosepiece and T-2 Threads

    The UAG II is built for system flexibility. Its primary body is a 2" nosepiece that slides directly into any 2" diagonal or focuser, such as the Baader 2" ClickLock clamp. For a more rigid, direct connection, the telescope side also features a T-2 female thread.

    This T-2 thread allows you to integrate the reducer into a solid, threaded optical train, which is ideal for binoviewing. You can attach it directly to a Baader T-2 prism diagonal, which in turn connects to your binoviewer, creating a compact and secure wide-field system. The actual focal reduction is variable and depends on the back focus distance you establish between the UAG II and your eyepieces, giving you control over the final magnification.

  • What makes the Alan Gee Universal Telecompressor (UAG II) different from other reducers?

    The UAG II is the only telecompressor on the market specifically designed to work correctly for visual observation with a binoviewer. Most reducers are optimized for imaging sensors and can introduce aberrations when used visually with the long light paths of binoviewers. The UAG II, based on a Roland Christen flat-field design, corrects for field curvature in SCTs while dramatically expanding the field of view for two-eyed observing.

    How does the UAG II improve binoviewing on a Celestron 8" EdgeHD telescope?

    On an 8" EdgeHD or standard SCT, a binoviewer provides comfortable viewing but with a very restricted field of view. The UAG II telecompressor widens this field significantly, allowing you to see large objects in context. For example, instead of seeing just the core of the Orion Nebula (M42), you can frame the entire structure from the Trapezium out to the fainter nebulosity in a single view.

    Is the focal reduction of the Alan Gee Universal Telecompressor (UAG II) a fixed value?

    No, the reduction factor is variable. It depends entirely on the distance between the UAG II's optics and the eyepiece field stop (or camera sensor). A longer distance results in a stronger reduction effect and a wider field. This allows you to customize the reduction by adding or removing T-2 extension tubes in your optical train.

    Can I use the Alan Gee Universal Telecompressor (UAG II) for imaging?

    While its primary design is for visual use, especially with binoviewers, its flat-field optical design by Roland Christen makes it suitable for imaging. It can help flatten the field of standard SCTs and provide a wider perspective for cameras with smaller sensors. The variable reduction allows you to fine-tune your imaging scale.

    What is the best way to connect the UAG II to a Baader Maxbright II Binoviewer on my SCT?

    For the most rigid and compact setup, it is recommended to build a fully T-2 threaded system. A typical high-performance configuration would be:

    • SCT Visual Back -> Baader T-2 Prism Diagonal -> UAG II Telecompressor -> Baader Maxbright II Binoviewer.
    This creates a solid, threaded connection that prevents any flexure and ensures perfect alignment.

    Do I need a 2" diagonal to use the UAG II?

    Not necessarily. While the UAG II has a 2" nosepiece that can be used in any 2" diagonal, its real flexibility comes from the T-2 thread on the telescope side. This allows for direct integration into T-2 systems like the Baader T-2 Prism or FlipMirror II, bypassing the need for a larger 2" diagonal entirely.

  • Baader Planetarium Warranty