Skip to content
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more
Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more

Baader Planetarium TZ-3S Telecentric System T-2 for SunDancer II and more

by Baader Planetarium
SKU BAA-1363070
CA$532.00 - CA$532.00
CA$532.00
CA$532.00 - CA$532.00
CA$532.00
Price Match Policy!
  • 3x Achromatic Telecentric System
  • Delivers a Parallel Light Beam for H-alpha Filters
  • Illuminates a 27.5mm Image Circle
  • 96mm Working Distance from T-2 Thread Base
  • Dual 1.25" and 2" Nosepiece
  • T-2 Thread for Secure Camera Connection
Backordered
Request Stock Alert
Availability Info
FREE Shipping in Canada
  • Description
  • FAQ
  • Specifications
  • In the Box
  • Downloads
  • Warranty

  • TZ-3S Telecentric System T-2 for SunDancer II and more

    The Baader TZ-3S is a 3x achromatic telecentric system engineered to deliver a perfectly parallel beam of light, a mandatory requirement for narrow-band H-alpha solar filters which must operate at a focal ratio of f/30. This standalone version, identified by its gold anodized label, illuminates a 27.5mm image circle over a forgiving 96 mm working distance. With its versatile dual 1.25"/2" nosepiece and secure T-2 camera-side thread, the TZ-3S serves as a high-contrast replacement for a standard Barlow lens for both critical solar and planetary imaging.

    The 3x Telecentric Advantage: Parallel Light and Stable Magnification

    Unlike a Barlow lens, which creates a diverging light cone and whose magnification changes with distance, a telecentric system produces parallel light rays. This core design principle ensures the magnification factor of the TZ-3S remains a constant 3x, regardless of where your camera or eyepiece is placed relative to its 96 mm optimal working distance. The result is a stable image scale and superior image quality, free from the optical compromises inherent in extending a Barlow's magnification with extension tubes.

    Achieving the Mandatory f/30 for H-alpha Etalons

    For sub-Angstrom H-alpha filters like the Baader SunDancer II, a telecentric system is not an optional accessory—it is an essential prerequisite. These filters rely on an internal etalon that only performs to specification when fed a perfectly parallel beam of light at f/30 or slower. Simply using a Barlow to increase a telescope's focal ratio to f/30 does not create a parallel beam and will severely degrade the filter's contrast. The TZ-3S correctly converts a standard f/10 telescope into an f/30 instrument, ensuring the etalon performs at its maximum theoretical contrast.

    Achromatic Imaging: Illuminating a 27.5mm Image Circle

    While designed for H-alpha, the TZ-3S is a fully achromatic system, corrected across the visible spectrum. This makes it a powerful tool for high-magnification lunar and planetary imaging, delivering higher contrast than simple Barlows or eyepiece projection. The system illuminates a 27.5mm image circle, making it an ideal match for the smaller sensors found in modern, high-speed planetary cameras that thrive at the high magnifications needed to resolve fine detail on Jupiter's cloud bands or the Cassini Division in Saturn's rings.

    Mechanical Interface: Dual 1.25"/2" Nosepiece and T-2 Threading

    The TZ-3S is built for secure, flex-free integration into any imaging train. On the telescope side, a dual-purpose nosepiece fits both 1.25" and 2" focusers and features safety kerfs instead of a simple groove, preventing tilts and ensuring a solid lock. On the camera side, a standard T-2 (M42x0.75) male thread provides a rigid, direct connection to cameras, filter wheels, and T-2 eyepiece holders, eliminating the potential for sag that can occur with simple thumbscrew connections.

    TZ-3S vs. TZ-4S: Matching f/10 vs. f/7.5 Telescopes

    Choosing the correct telecentric depends on your telescope's native focal ratio. While the TZ-4S offers a larger 36mm clear aperture, its primary purpose is different.

    • TZ-3S (Gold Label): This 3x telecentric is optimized for telescopes with a focal ratio of f/10, converting them to the target f/30 for H-alpha filters.
    • TZ-4S (Violet Label): The 4x telecentric is designed for faster telescopes around f/7.5, providing the necessary magnification to reach the same f/30 target.

    This standalone TZ-3S does not include the 2nm blocking filter required for the SunDancer II system; that component is only integrated into the red-ring version sold with the filter itself.

  • What is the main difference between the Baader TZ-3S Telecentric and a standard 3x Barlow lens?

    A Barlow lens creates a diverging light cone, and its magnification changes as you alter the distance to the camera sensor. The TZ-3S Telecentric System produces a parallel beam of light, which means its 3x magnification factor and image quality remain constant regardless of the working distance. This parallel beam is also a mandatory requirement for the proper function of narrow-band H-alpha solar filters.

    Why is the TZ-3S Telecentric mandatory for a filter like the Baader SunDancer II?

    The high-precision etalon inside a sub-Angstrom H-alpha filter requires a perfectly parallel, slow focal ratio (typically f/30) light beam to achieve its rated contrast and bandpass. Using a standard Barlow lens to reach f/30 does not create a parallel beam and will significantly degrade the filter's performance. The TZ-3S is specifically designed to produce this parallel f/30 beam, making it essential for critical solar observation.

    Can I use the standalone TZ-3S for planetary imaging with my f/10 SCT?

    Yes, absolutely. The TZ-3S is an excellent choice for this application. Its achromatic design is corrected for the entire visible spectrum, and it provides higher contrast than most Barlows. On an f/10 Schmidt-Cassegrain Telescope (SCT), it creates an f/30 imaging system, which is ideal for capturing fine details on planets like Jupiter and Saturn with modern high-frame-rate cameras.

    Will the TZ-3S work with my camera that has a sensor larger than 27.5mm?

    The TZ-3S is optically designed to fully illuminate an image circle of 27.5mm in diameter. While you can use it with a camera that has a larger sensor (like APS-C), you will experience significant vignetting (darkening) at the corners and edges of the frame. It is best matched with sensors that fit within this image circle.

    How do I attach the TZ-3S to my telescope and camera?

    The TZ-3S is very versatile. On the telescope side, it has a dual 1.25" and 2" nosepiece that slides directly into your focuser. On the camera side, it features a standard T-2 (M42x0.75) male thread for a secure, threaded connection to your imaging camera, filter wheel, or a T-2 eyepiece clamp.

    I have an f/7.5 refractor. Should I use the TZ-3S or the TZ-4S for my H-alpha filter?

    For an f/7.5 telescope, the TZ-4S (4x Telecentric) is the correct choice. To reach the required f/30 focal ratio for an H-alpha filter, you need a 4x magnification factor (7.5 x 4 = 30). The TZ-3S would only bring your system to f/22.5, which is too fast for the etalon to perform optimally.

  • Baader Planetarium Warranty